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Friday, September 30, 2011

Neanderthal - Human admixture

 
In America there are (according to the orthodox point of view) no Neanderthals, and there have never been any either. Neanderthals are Eurasian creatures. Yet, Amerindians have very high frequencies of haplogroups that are allegedly Neanderthal; some are even higher than many Old World groups. Some examples: the X chromosome’s B006, HLA-A*02 and HLA-C*07:02 among others. How can this be?

Furthermore, modern humans, Homo sapiens (HS) and Neanderthals (NH) do not share any mitochondrial DNA (mtDNA) , we do not have any (NH) Y chromosomes in our genome but we do carry other kinds of (NH) DNA.

Today's post will begin to explain these odd situations, but first lets brush up on our genetic knowledge:

 
DNA, mtDNA, X, Y, genes, haplogroups, SNPs and chromosomes

Nuclear DNA. Is the chemical structure that encodes the information needed to build a living creature. It is made up of a double helix of Deoxyribonucleic Acid (DNA) linked by four bases or nucleotides: adenine (abbreviated A), cytosine (C), guanine (G) and thymine (T). It is “nuclear” because it is found inside the nucleus of each cell in your body. It is inherited from both parents. These nucleotides (“DNA letters”) are arranged in “sequences”

Gene. It is a working subunit of DNA. Chunks of DNA (and RNA) that code a certain protein. There is a certain amount of reshuffling of genes in chromosomes.

Chromosome. The DNA molecules are packed, wound up, into minute structures known as chromosomes. Every cell in your body has two sets of chromosomes. You inherit one set from your mother and one set from your father. Each set has 23 chromosomes (total is 46). Of these, 22 are known as autosomes and 1 is a sex chromosome. Women have two X sex chromosomes, (XX) and men have an X and a Y sex chromosome (XY). The Y is transmitted from fathers to sons, who get their X sex chromosome from their moms. Girls get an X from each parent.

mtDNA, or Mitochondrial DNA is the specific DNA that small organelles called mitochondrion. These apparently were, eons ago, aerobic bacteria that established a symbiotic relationship with an anaerobic cell, taking up “food” inside the cell and providing it with energy. It lost its independent life, but retained its own DNA, which is not a double helix, but a circular shaped molecule. Although all cells in our bodies have mtDNA, you inherit yours from your mother, because it is her ovum or egg cell’s mitochondrion that passes on to you. Your dad’s sperm cells mitochondria remain outside the ovum, inside the flagellum (tail), and is discarded.

SNP , (pronounced “snip”), is a genetic variation in the DNA sequence in which one single nucleotide (i.e. A, T, C, or G) is modified and, kept through heredity. Let’s give an example: as you can see in the following three DNA sequences, there are variations in the second, fifth and ninth nucleotide. Each of these variations is a SNP, hence we name them SNP1, SNP2 and SNP3.

ACTTTGCTC    Haplotype 1 C  T  C
ACTTAGCTT    Haplotype 2 C  A  T
AATTTGCTC    Haplotype 3 A  T  C

SNP1 SNP2 SNP3

Haplotype, is a set of linked SNPs on the same chromosome

Haplogroup : A group which contains all the direct descendants of a single person (man or woman) who had, and passed-on a specific genetic marker (i.e. SNP) or mutation.

Getting the Neanderthal genes into modern humans
How did we, modern humans get the Neanderthal genes into our chromosomes in the first place? Yes, I do believe that there was sex involved, but whom with whom? And what was the outcome?

We can imagine groups of HS and NH living in overlapping territories and coming together occasionally perhaps for trade or to exchange articles. We can also envisage violent encounters with males killing males and raping the females. A more “romantic” setting would have a “one-night-stand” tryst during a get together around a camp site bonfire. The fact is that modern human beings and Neanderthals mated and had viable offspring (that carried the genes of NH parents in their bodies and managed to pass them on to their descendants so that it is still there, within our genes).

Lack of NH mtDNA. Mitochondrial DNA is passed on from mother to child. So if there were any Neanderthal mtDNA in humans, it could only have come from an ancestral Neanderthal woman. To survive until our days, since mtDNA is only transmitted by females, a continuous line of mother-daughters (who’s original “mom” was a Neanderthal woman), would have to span the 30,000 years that separate the last living Neanderthals from us.

However no Neanderthal mtDNA is found in humans, a paper [3] states that:

they estimate the maximum amount of admixture possible to observe no surviving Neanderthal mtDNA to be less than 0.1%, with no more than 120 admixture events during 12,000 years of overlap.[3]

In other words, one sexual encounter between a modern human man and a Neanderthal woman every century. Not very high frequency is it?

Anyway, since nowadays there is no Neanderthal mtDNA in HS, we can conclude that mating between HS men and NH women (was as limited as indicated by [3] : once every hundred years) or, if more frequent, it did not lead to a continuous lineage of hybrid N/HS women.

Possible explanations: (besides the “once a century” mating ratio), perhaps these trysts between HS and NH were few and far apart, and their outcome could have been sterile or they died without issue, in any case, they did not manage to survive long enough to pass on their genes to the next generations. Or if they did, these “generations” died out along the way, and the NH mtDNA died with them.
Or, since babies are brought up by their mothers (picture it: a HS male rapes or seduces a NH female and goes his way, with his HS clan. She gets pregnant and father is gone. So she brings up her HS/N hybrid son or daughter within her Neanderthal tribe or culture. The hybrid lives and has children and grandchildren, but the NH mtDNA, will stay within the Neanderthal tribe and will eventually die out with all the other Neanderthals, when these became extinct.
A male HS and a female NH breeding would therefore produce an admixture:

  • HS/N Hybrid boys: HS Y sex chromosome and NH X chromosome. NH mtDNA. Half of the autosomal DNA would be human, and the other half N.
  • HS/N Hybrid girls: HS X sec chromosome from father. NH mtDNA from mother, half the autosomal DNA from each parent, and NH X chromosome from mother.

DNA, the nuclear stuff
On the other hand, if Neanderthal men got human women pregnant, they would not pass on any NH mtDNA (the children would have their human mom’s mtDNA). But, the Neander-Dad would pass on his nuclear DNA . So, Man (N) and Woman (HS) would be a viable route to get Neanderthal DNA into our Homo sapiens cells.
This explains why we have Neander DNA (autosome chromosomes).

But there is more to it, we have not detected any Neanderthal Y (sex chromosome) in modern humans. A Man (N) would have passed his Y (N) chromosome to his sons, and they to theirs, forming a continuous lineage linking modern humans with NH Y chromosomes with their ancient NH relative 30 kya. So, why don’t we detect Y (N) in our modern humanDNA?

A 2006 paper found that the Neanderthal Y chromosome was “substantially more different from human and chimp Y chromosomes than are other chromosomes. This suggests that little interbreeding occurred, at least among the more recent Neanderthal species”[1].

But, even if there was little interbreeding, their “Y” chromosome should be present in modern humans together with their autosome chromosomes (snippets of which are part of our genes).

Why are there no NH Y chromosomes in the human genome?
One option is that all the male descendants of the original Neanderthal fathers died out (and their hallmark Y chromosomes with them).

Another option is given by Haldane’s law [2] which states that:

When in the offspring of two different animal species one sex is absent, rare or sterile, that sex is the heterozygous sex

Heterozygous sex meaning the offspring with two different sex chromosomes: XY, that is, the male. In plain english Haldane is saying that a male (N) and a female (HS) would have had more daughters than sons (boys would be rare). These few, if any (absent) boys would be carrying their Neanderthal father’s Y (N) chromosome and, they would be very probably sterile and therefore did not have children and could not pass on their Y chromosome to their sons.

The hybrid daughters on the other hand would be healthy girls (being homozygous, and having the same kind of sex chromosomes: XX). They would also have received half of their autosomal DNA and the NH X sex chromosome from their Neanderthal father and half of their autosomal DNA and their other X sex chromosome from their human mother, and, not being sterile, they would have passed them both on to their offspring . This is how we got the (N) autosomal DNA and the NH X sex chromosome into our genes.

Furthermore, the human mother would bring up her hybrid child within her HS group, which survived (well, most of them did) until today.

Summary

The only viable way of getting NH X sex chromosomes and their DNA sequences into our genes is if a HS woman and a NH man mated and had children. They would all have their mothers mtDNA and a 50/50 mix of NH and HS autosome chromosomes, their mom’s HS X chromosome and dad’s NH X chromosome.

The image below shows the possible outcome of a male NH and a female HS:
We represent the sex chromosomes XX for the women and XY for the men.
Regarding the original couple, in red are both NH chromosomes, a Xn that he will pass on to his daughters, and a Yn that will be inherited by his sons (who due to Haldane’s Rule will be few, absent or sterile), who won’t pass it on. The HS mom is shown as X1 X2. All descendants from this admixture will have the HS mom’s mtDNA (represented by a pale blue square placed under her). The NH mtDNA (pink square under dad) is lost and not passed on.
Neanderthal Human linage
All possible offspring of a Neanderthal - Homo Sapiens mating.
Copyright © 2011 by Austin Whittall

The two possible combinations of X chromosomes (NH and HS) are women. And both of these daughters carry mom’s mtDNA. They will marry HS spouses and pass on their mtDNA to all their children. As you can see, the females of the line (mother – daughter) will all carry the mtDNA of the first woman to mate with a Neanderthal. The boys on the other hand will have children but their mtDNA will be the one of their mothers (i.e. the orange square). Nevertheless, the Xn has an equal probability of getting transmitted along to the next generations.
As this happened when Humans and Neanderthal met, the window of occurrence is the time both NH and HS overlapped in the same habitat, it is the most likely way for Neanderthal males to come upon modern human women. But Where?

Was it in the original Neanderthal territory in Europe? In the Middle East? In Southwestern Asia? In Altai? Or (assuming that Neanderthals migrated into America), in America?

In my post Neanderthals in America some genetic proof I mentioned the B006 allele and O blood groups as a possible sign of Neanderthal presence in America. Are there other alleles belonging to Neanderthals and found in modern humans ( a sure sign of admixture)? Can we trace their source?

More markers of admixture, HLAs

A paper by Peter Parham [4] reports that a variety of Human leukoctyte antigens (HLAs) which help our immune system, such as the HLA-C*0702, quite common among Europeans and Asians but not found in Africa was also found in Neanderthal. The HLA-A*11 is shared by modern humans in Asia and... Denisovans, but it is nonexistent in Africa.

Parham suggests that HLA-C*0702 got into HS outside of Africa (hence its absence in Africa) by admixture with NH. And the same happened with HLA-A*11 (Denisovans bred with HS). As we were newcomers, these HLAs boosted our immune system to fight off illness (Denisovans and NH had evolved them over hundreds of thousands of years). Parham estimates that:

While only 6 per cent of the non-African modern human genome comes from other hominins, the share of HLAs acquired during interbreeding is much higher. Half of European HLA-A alleles come from other hominins, says Parham, and that figure rises to 72 per cent for people in China, and over 90 per cent for those in Papua New Guinea.[4]

The difference may be due to the hotter climate of the south having more diseases than the colder northern regions (i.e. Europe).

Where are these alleles found today: The maps below From [5] and [6] give a clear idea:

HLA in humans

HLA in Humans
Some HLAs purportedly Neanderthal, found in modern humans: current distribution.
Maps From [5] and [6]

The post is getting long, but as you can see, the A*11 is very high in Papua New Guinea, China, South East Asia, and Southern Asia. C*07:02 is high in the same regions plus Scandinavia and Very high in America.

Another paper by Abi-Rached [6], which we will delve in deeper in another post, comments about Neanderthal admixture as follows:

Thus, Neandertal admixture contributed B*07, B*51, C*07:02, and C*16:02-bearing haplotypes to modern humans, and was likely the sole source of these allele groups[6]

More in my next post...

Sources

[1] Rex Dalton, (2006). Neanderthal DNA yields to genome foray. News. Nature 441, 260-261 (18 May 2006) | doi:10.1038/441260b.
[2] Haldane, J. B. S., (1922). Sex-ratio and unisexual sterility in hybrid animals. J. Genet. 12:101-109
[3] Jason A Hodgson and Todd R Disotell, (2008) No evidence of a Neanderthal contribution to modern human diversity, Genome Biology 2008, 9:206 doi:10.1186/gb-2008-9-2-206
[4] Peter Parham, (2011) Primate-specific evolution of NK cell receptor recognition of MHC class I June 2011.
[5] Map source: http://www.pypop.org/popdata/2008/byfreq-C.php
[6] Abi-Rached, et al. (2011). The Shaping of Modern Human Immune Systems by Multiregional Admixture with Archaic Humans Science 25 August 2011: 1209202DOI:10.1126/science.1209202


Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia
2011 International Year of Forests
2011 International Year of Forests Copyright 2009-2011 by Austin Whittall © 

Tuesday, September 27, 2011

Denisovans and America

 
My previous post (first Asians were not erectus) concluded with a reference to a paper on Denisovans which stated that: “ modern humans acquired the HLA-B*73 allele in west Asia through admixture with archaic humans called Denisovan” [1].
Lets dig a little deeper into this HLA allele.

A very uncommon HLA allele

Among all the HLA-B groups (which add up to thirty six ( 36 varieties): B*07, B*08, B*13.... B*83) it is the one with the least quantity of specific HLA halotypes. In other words each of these thirty six groups have their own variations. For instance HLA-B*07 has 124 different allotypes, HLA-B*15 has 221 allotypes.

The one that we are interested in, HLA-B*73 has only two: B*73:01 and B*73:02 (which was detected in only one person in Abi-Rached’s study, so we can set it aside).

Globally its frequency within the human population is quite low, less than 1%, and in most of the world it is closer to zero. But, some places show a very high frequency in comparison to others.

The “raw” data is shown in the following table which combines data from [1] and [3]:

Frequency / Place – ethnic group
(Data from [1] unless indicated otherwise. )
4.90% Parsi
2.30% Israel Jews
2.00% United Arab Emirates
1.10% Cameroon Beti
0.90% Georgia Tiblisi,
0.90% Bulgaria
0.90% Morocco Casablanca
0.90% Burkina Faso Mossi
0.80% Russia Tuva,
0.80% Oman
0.70% Average for SW Asia [3]
0.60% Albania
0.60% Cameroon Bamileke
0.50% Mongolia Khalkha
0.50% Pakistan Pathan
0.50% Iran Baloch
0.50% Tanzanaia Dodoma Kongwa
0.50% Israel Druze
0.50% Algeria
0.40% Average for NE Asia [3]
0.40% Saudi Arabia
0.40% Turkey
0.30% Bangladesh Dhaka Bangalee
0.30% Jordan Amman
0.30% Uganda Kampala
0.20% Kenya Nandi
0.20% Kenya Luo
0.20% Zimbabwe Harare Shona
0.20% Rwanda
0.20% Greece
0.20% Macedonia
0.20% North America, Hispanic [3]
0.10% Europe [3]
0.15% Mexico Sonora, Seri [3]

Comments.

  • We see that it is strongly concentrated in the Middle East and SW Asia, across central and northern Africa and in the Balkans and Caucasus (home of the Dmansi people).
  • There are some local “islands” or “singularities”:

    • in Mexico (the Seri natives). We will look into them later.
    • in Mongolia (close to the Denisovans?)
    • in the Russian republic of Tuva (right next to Altai, homeland of the Denisovans)
  • The highest frequency is in Pakistan (more later)
  • The Israeli Jews and Druze together are second highest.

Some maps

I love maps! As they show things more clearly than a table. Fortunately, all this data was placed in a map by Abi-Rached [1]. In which he shows the Current distributionA”. Then, trying to explain the anomalously high Pakistan figure, he defines two models which take into account that the Parsi population now living in Pakistan came from Persia, escaping religious persecution. Figure “B” shows one of these models (they are both very similar) which considers the city of Nishapur as the refugee of the persecuted Zoroastrians. There is yet a third map, “C” which shows the global distribution of the HLA-B*73:01 allele, now including Australia and America, as it comes from another source [2] it differs slightly from the data given by [1]. Nevertheless, Maps “A” and “C” are very similar and show the same trend.

HLA-B*73 frequencies
Map showing the global distribution and
frequencies of HLA-B*73:01 (adapted from [1] and [2]
.

Remarks

The maps clearly show some “hot spots” in Mongolia and the Altai Region and an anomaly in Western Mexico (the Seri natives land).

Could the swath across Africa be related to Arab slave trade and possible mixing with locals? Or is it more ancient and shows a returning flow of humans into Africa after acquiring the HLA-B*73 from the Denisovans.

The Balkans, may be due to the Turkish occupation of that area between the 14th and the 19th century.

We see tha China, SE Asia, Australia, Southern Africa and Mots of America and Europe have less than 0.5% frequencies.

So, what does all this mean?

If, as Abi-Rached contends, modern humans picked up the HLA-B*73 allele from Denisovans, they must have “trekked” through Denisovan terrritory. Perhaps the areas where the HLA-B*73 frequency is highest corresponds with the Denisovan homeland: because the humans who settled in the Denisovan territory would have had more time /chances to “mix” with them and breed future generations carrying Denisovan HLA alleles. And from there they would have dispersed to other locations taking the HLA alleles with them.

So, if the maps are correct, Iran is the homeland of the Denisovans. Pakistan’s high figures are just a coincidence, because it is there where the Persian Parsis moved to save their lives.

The Druze and Israeli Jews are also another hot-spot which we will look into later (they are linked to other genetic evidence) , but the high frequency in this region may have two possible explanations:

  • It probably indicates that Denisovans were living in that area along the Jordan River valley
  • Perhaps it reflects the comings and goings of the Jewish people (remember that they were held captive in Babylon (Babylonian exile) after Nebuchadnezzar forced them in o exile after conquering the kingdom of Judah ca. 590 BC. They probably picked up the “Persian” HLA-B*73 during their captivity there, Persia is right next to Israel. Furthermore, after the creation of the state of Israel, many Jews living in Iraq and Iran were forced to move out and migrate to Israel.

Map “C” clearly shows the hot spot centered in the Middle East and fanning out north west into the area where “late” Denisovan remains were later found (Altai). Suggesting perhaps that the Denisovans occupied this area and later were forced to less favorable lands such as Altai and Southern Central Siberia / Mongolia.

Coincidentally this region (Levant, Caucasus and Altai / South Central Siberia) is where Neanderthal remains have also been found. This may just indicate that it was an area where the last remnants of dwindling homind populations found refuge (i.e. Neanderthals and Denisovans).

Denisovans

Since those (H. heidelbergensi?) who would later become Neanderthals and modern humans split from the Denisovans about 1 million years ago, and Denisovans survived until about 30-50 kya, we can imagine that they lived for 1 million years in this same territory. Let’s put this in context and link it to our previous post.

We had said that about 2 million years ago, H. habilis left Africa, settled in the Caucasus and there evolved (1.75 M years ago) into the Dmanisi people Homo georgicus. These in turn led to H. erectus (which peopled Southeastern Asia and China, moved back to Africa and into Europe). The Dmanisi may have also moved on into America and into Flores Island, where they became the local Hobbits.

All of this happened before 1.5 million years ago. Then there is a blank space of half a million years. The next solid evidence is that 1 million years ago, the Denisovans split from the branch that led to modern humans and Neanderthals: the H. heidelbergensis.

What happened in the Dmanisi homeland during the period 1.5 to 1.0 million years ago? Had all the Dmanisi disappeared, becoming H. erectus and migrating to East Asia, Africa (or America)? Did any remain behind, to become the ancestors of both H. heidelbergensis and the Denisovans? Did they die out?

I have not read about any H. erectus fossils being found in South Western Asia, so if the Dmanisi stayed there, and did not become extinct, they had to become something else.

Getting back to Africa, H. ergaster is said to be the ancestor of H. heidelbergensis and of modern humans, so it is them, the H. ergaster who is the most likely common ancestor of Denisovans and the rest of mankind. And, on the “human - Neanderthal” branch, immediately after the Denisovan split, we can fit H. heidelbergensis, see below (it is a revised version of the tree published in yesterday's post):

phylogenetic tree
Revised phylogenetic tree.

This does not tell us anything about the fate of the Dmanisi though. It says that Denisovans split before the appearance of H.heidelbergensis, and marched out of Africa towards the Middle East, settling in South Western Asia where, they would later mix with modern humans and maybe, Neanderthals.

The Seri natives in Mexico

The the Seri language is a linguistic isolate which has no apparent connection with any language in the United States or Mexico. They are only about six hundred Seri left, and a Genetic study [4] seem to link them to the Warao Indians of Venezuela and suggest that the Seri’s ancestors were part of a first wave of migrants into America.[5]

The paper [4] however does not mention HLA-B*73.

There is however more data in Abi-Rached’s paper:

Worldwide, ~98% of people carrying B*73 also carry C*15:05[1]

This C*15:05 (also known as Cw*15:05) as seen in the following maps, is also present in Mexico – see red arrow, as well as all the other Asian regions that have a high frequency of B*73. The maps are from [1] above and [2] bottom and show the same distribution (with the exception of SE Asia, where there is a spot with very high frequency of C*15:05 in Indochina which is not shown in the bottom map.

We have to understand why the Seri have such a high frequency of B*73 and Mexicans of C*15:05 in comparison to the rest of the American Indians.

That will be the subject of a future post.

Map showing the global distribution and
frequencies of HLA-C*15:05 (adapted from [1] and [2]
.

Sources

[1] Abi-Rached, et al. (2011). The Shaping of Modern Human Immune Systems by Multiregional Admixture with Archaic Humans Science 25 August 2011: 1209202DOI:10.1126/science.1209202
[2] Map showing B*7301 dispersion is from This page: Allele frequency net: a database and online repository for immune gene frequencies in worldwide populations. From: Gonzalez-Galarza FF, Christmas S, Middleton D and Jones AR Nucleic Acid Research 2011, 39, D913-D919 and based on Solberg et al (2008) the original is at: http://www.pypop.org/popdata/2008/maps/B-7301.gif
[3] dbMHC Home, NCBI
[4] Infante, E., A. Olivo, C. Alaez, F. Williams, D. Middleton, G. de la Rosa, M. J. Pujol, C. Duran, J. L. Navarro, and C. Gorodezky. ( 1999). Molecular analysis of HLA Class I alleles in the Mexican Seri Indians: Implications for their origin. Tissue Antigens 54:35-42.
[5] Jim Hill, David Yetman, A world revealed by language: a new Seri dictionary and unapologetic speculations on Seri Indian deep history


Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia
2011 International Year of Forests
2011 International Year of Forests Copyright 2009-2011 by Austin Whittall © 

Monday, September 26, 2011

The first Asians were not Homo erectus

 
Although I have been following paleoanthropology through scientific magazines for decades, recent discoveries have overturned what I have previously learned about human dispersion out of Africa. So, before embarking on our “Neanderthal in America” thesis lets brush up on what is currently going on in the hominid field so that we can put things in perspective.

The late Twentieth Century Hominid scenario

What I knew was this: after a long chain of Australopithecines, the first member of genus Homo appeared.
It was the primitive forbearer of mankind,Homo habilis (Latin for skilful man) who lived in Eastern Africa about 2.3 M years ago. They had a small brain (600 cm3) and were quite small (1.3 m - roughly 4.25 ft.) yet they developed a simple stone tool technology known as “Oldowan”. They disappeared about 1.4 M years ago.

Oldowan stone tools were of the “core and flake” variety, in which a stone core was hit with a hammer stone chipping it to produced flakes and leaving a “chopper core” both flakes and core were used to cut, bash and scrape.
It is the earliest (oldest) stone tool industry dating back to about 2.6 M years ago. It was replaced 1.7 M years ago by the more advanced Achulean technology.

If Oldowan tools are found, you can be certain that they predate the discovery of Acheulean tools and therefore belong to a group that predates the inventors of these tools.

About 1.8 M years ago, Homo erectus (upright man) appeared, bigger and brainier (850 to 1,100 cm3) . They were the first humans to leave Africa, as their remains have been found mostly in Indonesia and China. They, in turn were replaced by an out of Africa wave of modern humans some 70- 30 kya. H. erectus produced a more “advanced” stone technology, the “Acheulean” and also learned to use fire.

Acheulean stone tools were also flakes knocked off a core, but these flakes were reworked several times, chipping their edges, to produce a sharp blade. The worked core resulted in a pear-shaped “axe”. The working of the core produced tools which were more symmetric than the Oldowan ones.

The H. erectus stock that remained in Africa is known as Homo ergaster (working man)kept on evolving, producing a group that left Africa and peopled Europe via the Middle East, the H. heidelbergensis (Heidelberg man – where its remains were first found, in Germany), who then evolved ino H. neanderthalensis (After the site of Neanderthal in Germany).

Those that remained in Africa continued evolving, becoming Homo Sapiens, (wise man), modern humans.

The changing picture

That was the neat former picture, but science evolves with new findings at new sites and novel techniques (genetic ones) which have somewhat altered it. Fossils found in Spain, Georgia and Russia plus genetic analysis of hominid remains have redrawn this nice picture.

To make it worse, you should bear in mind that there is little consensus among scholars regarding the relationship between all these hominids as dates are sometimes uncertain or, the fossil evidence is lacking.
Anyway, as I am not a scholar I can allow myself to speculate freely!

Dmanisi hominid

A variety of human dating to 1.75 M years ago, it is also known as Homo georgicus, (Man from Georgia – where it was found). Their small brain size and rounded shape of their skulls places them closer to H. habilis than to H. erectus, and their discoverers wrote:

We suggest that the ancestors of the Dmanisi population dispersed from Africa before the emergence of humans identified broadly with the H. erectus grade.[3]

Furthermore, their tools were “Oldowan” [4] (“primitive”).

Did H. habilis leave Africa first?

The discoverers of Dmanisis suggest that these hominids are a variety of Homo habilis that left Africa, crossed the Middle East and moved on into the Caucasus (Europe and Asia) about 2 M years ago. If so, they were the first “humans” to do so.[2]

H. erectus originated in Asia

They also suggest that the Homo habilis “Dmanisi” evolved in Asia, becoming an “early” variety of H. erectus.[2]

And now things get interesting: they split into different branches of H. erectus, some stayed in Asia and walked east, the ancestors of later Java and Peking men (the H. erectus remains found in Indonesia and China). Others went back, south and returned home to East Africa, originating a more slender African erectus, H. ergaster, who would eventually give rise to us, modern humans.[2]

The map below shows the path out of Africa (from Olduvai gorge) towards Georgia (Dmanisi) of our tiny African H. habilis with his Oldowan tool industry (Red arrow).

At Dmanisi they evolved into H. erectus, who acquired the Acheulean stone tool technology and took it with them back to Africa, but, surprisingly they did not take it along with them in most of their journeys:

  • Eastwards into China and Indonesia (no tools found in Java though, perhaps they used bamboo cane for their tools). Their bones have been recovered from the sites at Sanigran (1.66 M years ago) and Yuanmou Man (1.7 M years ago) , and their tools at Nihewan (1.65 M years ago) however they were “more comparable to Oldowan localities in Africa”. Close to Beijing, later H. erectus remains have been found but the only Acheulean tools found in China are much more recent (ca. 800 kya). Pale blue arrows across southern Asia.
  • West, into Europe, where H. antecessor was found in Spain (Sierra de Atapuerca) where they lived between 1.2 M years ago and 780 Kya. They also used “Oldowan” tools (perhaps they moved west before acquiring the Achulean know-how?). Pale blue arrow through Europe.
  • A third group walked back, through Israel (Ubeidiya site’s Acheulean tools 1.5 M years old) into Africa, across the north (Algiers site at Ain Hanech 1.8 M years ago with “Advanced Oldowan tools”.) the rest moved south back towards East Africa. Pale blue arrows into Africa.

homo habilis dispersion across the globe
Map showing the possible dispersion of H. habilis across the globe.
Copyright © 2011 by Austin Whittall


Hobbits and American ape men

The minute Flores Island “hobbit”, Homo floresiensis is also more primitive than h. erectus, which leads us to ask: Was he the outcome of an H. habilis group that split from those moving north, and migrated east, into South East Asia and Indonesia?

And, for us, keen on finding out more about the possible origin of our Patagonian ape-like creatures, could tiny H. habilis have kept on walking across Asia and reached America via Bering? (both the Hobbit route and the American path are shown with green arrows in the map above).

There is some evidence of human presence in the Indian Subcontinent: “hominid-struck stone artefacts [...] ca. 2 million years old”[1] In artifacts near Riwat, northern Pakistan, on the Indo –Gangetic floodplains. No bones have been found, so it is not possible to identify their makers, but we know that they are “Oldowan” so they are pre-H. erectus.

Similar tools have been found in China, and date back to 2 M years at Renzidong in Anhui, Eastern China. But, again, human bones are lacking.

So we have ancient human presence in India and China, 2 million years old, contemporary to the H. habilis out of Africa event. These probably kept on moving into America (the north group) and to the southernmost island, at Flores.

Archaic modern men

There is a clear differentiation between those “primitive” H. erectus, H. ergaster and H. antecessor and the more “modern” variety that later spread out across Africa, Europe and the Middle East. The latter had a larger brain, and have been found at different sites.
The transition between both “varieties” is unclear because the period covering it (1,000 to 600 kya) is not very abundant in hominid fossils all across the Old World.

We know that something happened at that time, we are not quite sure where it happened, but the outcome was a brainier mankind.

  • Europe . H. heidelbergensis. Their remains at Atapuerca, Spain date back to about 600 kya. Their tools are Acheulian. Where they replaced the H. antecessor people. They had Acheulean assemblages. They are also found at Heidelberg and Steinheim (Germany), Arago (France), Petralona (Greece), Sima de los Huesos (Spain), Boxgrove (UK) and Ciampate del Diavolo (Italy).
  • Africa. Bodo and Kabwei sites (which some group within Homo rhodesiensis).
  • Asia. Dali and Jinnishuan in China

Some 300 kya, they gave rise to Neanderthals in Europe and the Levant, and Modern Humans in Africa some 150 – 200 kya. But there is another mysterious group, the Denisovans:

Denisovans

The site located in Altai, Russia, produced a fossils of a new species of hominids. The Denisovans.

These Denisovans differ from both H. neanderthalensis and H. sapiens but share a common ancestor with them about 1 M years ago. The Denisovans may represent an unknown homind that left Africa and originated the human and Neanderthal ancestors. They managed to survive until 40 kya.

Using DNA extracted from a finger bone found in Denisova Cave in southern Siberia, we have sequenced the genome of an archaic hominin to about 1.9-fold coverage. This individual is from a group that shares a common origin with Neanderthals. This population was not involved in the putative gene flow from Neanderthals into Eurasians; however, the data suggest that it contributed 4–6% of its genetic material to the genomes of present-day Melanesians. We designate this hominin population ‘Denisovans’ and suggest that it may have been widespread in Asia during the Late Pleistocene epoch. A tooth found in Denisova Cave carries a mitochondrial genome highly similar to that of the finger bone. This tooth shares no derived morphological features with Neanderthals or modern humans, further indicating that Denisovans have an evolutionary history distinct from Neanderthals and modern humans [5]

The paper also showed that Neanderthal and modern humans share a common ancestor 800 kya and that they split apart between 270 and 449 kya. The Neanderthals and Denisovans diverged 604 kya and 804 kya from modern humans.[5]

A possible cause for these exceptional genetic traits in Denisovan remains of people who lived 30 to 50 kya, may be the following:
  • Denisovans retained features that Neanderthals and humans lost
  • The Denisovans acquired them from "some even more diverged hominin[5] that is, extant out of Africa H. habilis or their later descendants.
  • Reversal to ancestral traits.

The molar that was recovered from a Denisovan shows that it was much larger than those of early modern humans and Neanderthals but similar to those of H. erectus and H. habilis. Could they be some relict descendants of H. habilis?

denisovan phylogenetic tree
Denisovan, Neanderthal and humans.From [7]


The Image above is “Phylogenetic tree” adapted from Paabo.[7] The actual dates are 1.3 Mya – 779 kya for the divergence between Denisovans and Neanderthal / Humans, and 321 – 618 kya (mean 466 kya) for the Neanderthal – Sapiens cleavage.

Though some disagree [6] and interpret the data differently.

The HLA-B*73 allele and Denisovans

Human leukocyte antigens (HLAs), are a family which has roughly 200 genes which are crucial for our survival as they allow our bodies to fight off diseases. They make up our immune system. They are also among the most variable of human genes: there are hundreds of variations (known as alleles) of each of these genes in the human population. And thanks to them, we are tweaked to react to different diseases and adapt to new ones.

Modern humans walking out of Africa in small groups had, most likely a very limited quantity of HLA alleles, and these were specially adapted to those diseases found in Africa.

When these modern humans reached Asia, with two million years of parasite-human host adaptation, between the first waves of hominids leaving Africa and the native Asian disease agents, they were in deep trouble. But, if they “mingled” (i.e. mated) with a native Asian hominid population, their offspring would have inherited Asian HLAs, well adapted to indigenous diseases.

A study has proven just that, and guess who passed on the HLAs to modern humans? Yes, the Denisovans (below is an abstract from a paper –bold face mine):

Whole-genome comparisons identified introgression [genetic input] from archaic to modern humans. Our analysis of highly polymorphic HLA class I, vital immune system components subject to strong balancing selection, shows how modern humans acquired the HLA-B*73 allele in west Asia through admixture with archaic humans called Denisovans, a likely sister group to the Neandertals. Virtual genotyping of Denisovan and Neandertal genomes identified archaic HLA haplotypes carrying functionally distinctive alleles that have introgressed into modern Eurasian and Oceanian populations. These alleles, of which several encode unique or strong ligands for natural killer cell receptors, now represent more than half the HLA alleles of modern Eurasians and also appear to have been later introduced into Africans. Thus, adaptive introgression of archaic alleles has significantly shaped modern human immune systems.[8]

Now this is really interesting, moreso because this HLA-B*73 allele is not very common and appears at very low frequencies among the modern human population.
But this post has got too long! Next post will look into the B*73 and its current global distribution (yes, it is found in America, but in very strange locations, and with very odd natives! Also it is found in ... Altai, the Denisovan enclave and the Middle East, home to the Druze, which also are linked to America... but more in my next post).

Sources
[1] R. W. Dennell, H. M. Rendell and E. Hailwood, (1988). Late Pliocene Artifacts from Northern Pakistan. Current Anthropology. Vol 29, No. 3. Jun. 1988. pp. 495-498.
[2] John g. Fleagle. Out of Africa. pp 249 – 277
[3] Abesalom Vekua, David Lordkipanidze et al. (2002). A New Skull of Early Homo from Dmanisi, Georgia. Science 5 July 2002: Vol. 297. no. 5578, pp. 85 - 89 DOI: 10.
[4] Deborah Barsky, (2009), An Overview of Some African and Eurasian Oldowan Sites: Evaluation of Hominin Cognition Levels, Technological Advancement and Adaptive Skills. In Interdisciplinary Approaches to the Oldowan . Vertebrate Paleobiology and Paleoanthropology, 2009, 39-47, DOI: 10.1007/978-1-4020-9060-8_4
[5] Reich, David, et al. (2010). Genetic history of an archaic hominin group from Denisova Cave in Siberia
Nature 468, 1053–1060 (23 December 2010) doi:10.1038/nature09710
[6] Caldararo, Niccolo and Guthrie, Michael. A Note On The Denisova Cave mtDNA Sequence. Available from Nature Precedings (2011).
[7] Krause, Johannes; Fu, Qiaomei; Good, Jeffrey; Viola, Bence; Shunkov, Michael; Derevianko, Anatoli and SvantePääbo. (2010) The complete mithocondrial DNA genome of an unknown hominin from southern Siberia doi:10.1038/nature08976. Letters. Nature 464, 894-897 (8 April 2010)
[8] Abi-Rached, et al. (2011). The Shaping of Modern Human Immune Systems by Multiregional Admixture with Archaic Humans Science 25 August 2011: 1209202DOI:10.1126/science.1209202


Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia
2011 International Year of Forests
2011 International Year of Forests Copyright 2009-2011 by Austin Whittall © 

Friday, September 23, 2011

Yaguaru or Water Tiger, another description

 
Below I copy the text written by an Englishman, Samuel Hull Wilcocke (ca. 1766 - 1833), who quotes unknown sources in his book about Buenos Aires (very likely he embellished the description given by father Faulkner) and descripes the Yaguaru.

Nevertheless, the donkey sized wolf headed animal, with talons, tusks and shaggy hair is quite odd, and gives us another depiction of this creature:

Yaguaru an Indian name signifying water tiger is the appellation given to a kind of amphibious animal inhabiting the river Parana which is very seldom seen and of which no accurate description has been given It is vaguely described as being of the size of an ass with a head like a wolf and stiff erect ears sharp talons and strong tusks thick and short legs long shaggy hair and a long tapering tail

The book's text is:



The above text is from: Samuel Hull Wilcocke, (1807). History of the viceroyalty of Buenos Ayres London. pp. 466.

The upright (Stiff erect) ears are quite different from those of other Patagonian animals said to be a "Water Tiger", such as the "tiny eared" Iemisch.


Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia
2011 International Year of Forests
2011 International Year of Forests Copyright 2009-2011 by Austin Whittall © 

Thursday, September 22, 2011

Neanderthals migration to America - Part I

 
dispersion of Neanderthal into America
A revised view of Neanderthal's distribution in Asia and possible entry route into America. Copyright © 2011 by Austin Whittall

The map above shows what I drew in a previous map but puts it in context. You can see the entry route of modern humans (H. sapiens) into Asia through Sinai and the southern tip of the Red Sea and the tip of the Persian Gulf (see the lower sea level and the coast line during Ice Ages).
Ice sheets covered the high mountains of Eurasia and blanketed the northern part of Europe and central Asia.

These ice fields cut off the drainage of Siberian rivers (which flow north) and acted as ice dams, forming the biggest lakes that the world has ever seen Lakes Komi and West Siberian Lake. The water backed up and found a southern outlet into the Aral Sea and from there to the Caspian Sea, which filled in its current depression (nowadays this "sea" is below sea level) and led it to flow west into the seas of Azov and from there into the Black sea, at that time a lake as were all the others (freshwater due to glacial ice melt and not salt water as they have now).

These rivers were mighty barriers to Neanderthal and would have been uncrossable, they were a barrier to further expansion, as was the northern glaciers.

We have seen that Neanderthal reached the mouth of the Indus River, on the border between Pakistan and India. Why did they stop there? Perhaps ancient H. erectus population in India impeded it, or the weather / vegetation was too balmy for the Neanderthals, used to living in the icy tundra.

They would have gone north, from Pakistan, Afghanistan and Iran towards Altai, where their most distant remains have been found (to date).

I see nothing that would have made them stop there. They could have gone southeast, into what is now China, but perhaps there was no game to hunt or, again, H. erectus blocked the way.

They would have followed the southern edge of the tundra, just north of the mountains that separate Mongolia from Russia, on and on, towards Beringia, and once across it, into America.

Lets go into details! in my next posts.


Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia
2011 International Year of Forests
2011 International Year of Forests Copyright 2009-2011 by Austin Whittall © 

Monday, September 19, 2011

Neanderthal in India?

 
Neanderthal range revised
A revised map of Neanderthal distribution Range. Copyright © 2011 by Austin Whittall

After writing my last blog, I wondered if Neanderthals reached India or Pakistan (since their tell-tale B006 and O blood group is found there), and though the maps I have seen and most articles I have read place them in Europe, the Middle East and the Caucasus (see the map that I posted in my first post on this series on "Neanderthals"), I decided to check out if there were any traces of them elsewhere.

Guess what? Yes, they have been found in the Indus river delta area!

A paper by Biagi and Starnini (2011) [1] clearly states this:

The Levalloisian assemblages discovered in Sindh, which display very characteristic features, among which are faceted and "chapeau de gendarme" butts, can be attributed to Middle Paleolithic human activity in the area, most probably related with the south-easternmost spread of Homo neanderthalensis. This species might haver reached the Indian Subcontinent either from the Anatolia-Caucasus-Mesopotamia corridor or across the southern regions of the Arabian Peninsula"[1]

They conjecture that the Indus delta was a geographic barrier.

These "Levalloisian" assemablages are a lithic technology (stone chipping) which is characteristic of Neanderthal stone working or Mousterian tool culture which dates to the Fourth or Würm Glacial Period some 40,000 years ago. Mousterian tools spanned the period between 300,000 and 30,000 BP, and disappeared with the demise of the Neanderthal.

Was the Indus a barrier?

Biagi and Starnini cite Stock, who wrote about "Potential geographic barriers [...] The Himalayas form a natural barrier between India and norterh Asia while the Indian subcontinent is bound on the West by both the Sulaiman Mountain Range and the Indus river delta which was likely comprised of salt flats and marshes during OIS4 [...]"[2]

The OIS4 mentioned in the article is a distinctive warm and cold period called "Oxygen Isotope Stages" (OIS), the OIS 4 - 73,000 to 63,000 years ago was a cold one.But it is likely that Neanderthal crossed the area before OIS4. Or, did not find it such a challenge after all (hadn't they walked out of Africa, crossed the Rhine, the Danube, the Volga and the Bosphorus?).

An expanded Neanderthal territory

Further north, identifiably Neanderthal bones have been found in Uzbekistan (Anghilak cave) [3]. Also in that same region bones were found in the 1930s at Teshik Tash cave in Uzbekistan and the Okladnikov cave in the Altai Mountains region of Siberia, they had not been clearly identified until now, because the fragmented remains were hard to classify. However modernt technology allowed them to be subjected to DNA testing which confirmed that they were Neanderthal remains3.5*350 [4].

By the way, there is a Mongolian "wild man" allegedly living in the Altai Mountains, the Almas... perhaps an extant Neanderthal. A place which is strikingly similar to the Bigfoot habitat in North America or the Southern Andean temperate forest.

Some 33,000 years ago, the Neanderthal also moved north into the Arctic regions of Russia, north of the Urals, and 1,000 km north of their "accepted" territory, is a site at Byzovaya, where their stone tools have been found [5].

So I have re-drawn the map based on these findings (it is shown above, at the beginning of this post).

Out of Asia?

So here we have a Neander who has gone well beyond its formerly accepted territorial boundaries. Who lived in the lower Indus river and in the Altai Mountains as well as northern Russia.

He seemed adapted to survive under harsh conditions. Could he have walked up the Indus, across the Himalayas or, across Siberia towards Beringia and entered America?

Man did. And Neanderthal was so similar to us. Maybe he did it too!

Sources

[1] Paolo biagi and Elisabetta Starnini, (2011). Neanderthals at the South-Easternmost edge: The spread of Levalloisisan Mousterian in the Indian Subcontinent. Published in "Papers in Honour of Viola T. Dobosi", ed. by K. T. Biro & A. Marko, Hungarian National Museum, Digital publication, Budapest, pp. 5-14.
[2] Jay T. Stock and Marta Mirazón Lahr (2007). Cranial diversity in South Asia relative to modern human dispersals and global patterns of human variation
In Petraglia, Allchin, eds. The Evolution and History of Human Populations in South Asia, Springer, Berlin, pp. 245-268
[3] Michelle Glantz, Rustam Suleymanov, Peter Hughes,Angela Schauber, (2003). Anghilak cave, Uzbekistan: documenting Neandertal occupation at the periphery
Antiquity Vol 77:295 March 2003.
[4] Johannes Krause, Ludovic Orlando, David Serre, Bence Viola, Kay Prüfer, Michael P. Richards, Jean-Jacques Hublin, Catherine Hänni, Anatoly P. Derevianko & Svante Pääbo (2007). Neanderthals in central Asia and Siberia Nature 449, 902-904 (18 October 2007) | doi:10.1038/nature06193; Published online 30 September 2007
[5] Bruce Bower Stone Age cold case baffles scientists Neandertals, or possibly ancient people, took polar express June 4th, 2011; Vol.179 #12 p. 8.


Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia
2011 International Year of Forests
2011 International Year of Forests Copyright 2009-2011 by Austin Whittall © 

Neanderthal - index

 
Neatness makes it easier to find things, so I am making this index to list all Neanderthal / Neandertal posts, for future reference, I will link to this post from the links on the sidebar.

Neanderthal - Human gene admixture,some information on the genes that we share with Neanderthals, and why we do not carry their Y chromosomes or their mtDNA in us despite carrying part of their DNA sequences...

Minnesota skulls In 1968 two Neanderthal-like skulls with low foreheads and large brows were found in Minnesota. As for dating, University of Minnesota scientists said they were reluctant to destroy any of the material, although carbon-14 ...

Part 1 Neanderthal in America. Some genetic proof to back the presence of Neanderthals in America: X chromosome B006 and RRM2P4 mutations....

Part 2. Neanderthal in America. A link between the Indian Subcontinent and America regarding B006 and RRM2P4.

Neanderthal in the Indian Subcontinent, a look at "Neander's" territorial range and recent findings that place them in Pakistan, Altai, Arctic Russia and Central Asia.

Migration to America Part 1, a new revised map of Neanderthal's range and possible route to America. More to come in next post...

More to come!



Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia
2011 International Year of Forests
2011 International Year of Forests Copyright 2009-2011 by Austin Whittall © 

More on Neanderthal in America

 
Continuing with the "American Neanderthals"... I took another look at the map showing the B006 haplotype in the X chromosome which I had posted in my previous entry, and was surprised to notice that there is a high "density" of this mutation in the Indian Subcontinent.
So I focused on the regions with high concentration of this haplotype and marked them on the map, which you can see below:

B006 mutation
Worldwide distribution of B006 haplotype based on a worldwide sample of 6092 X chromosomes. Areas with high percentage are highlighted . From [1]

As you can see, there are three areas within America that have a high density of B006 mutation:

1. Amazon: northern Bolivia, south western Peru and western Brazil. A relatively out of the way place, which due to its isolation could account for a high ratio of a rare mutation.
2. Meso America and northwestern South America, from Colombia to Yucatan.
3. Western Canada and the US (British Columbia, Oregon, Washington and California. (The "odd" Yuki live in California).
4. Europe excluding the Balkans and Southern Italy.
5. Indian Subcontinent.

The Indian Subcontinent's oddity

Why India and Pakistan? The map shows that the percentage of humans with B006 mutation drops off as you move out of Europe into Asia and across Asia (in China it drops to 0% of the population).

It picks up in Beringia and increases dramatically in America.
But, why so high in the Indian Subcontinent (yes, I also saw the Australian increase after dropping off to zero in Indonesia. What can that mean? Perhaps the "Kow Swamp" people took it there: they were robust hominids which survived until about 10,000 years ago in Australia, co-existing with modern humans).

Getting back to India and Pakistan. I recalled that I had posted about another mutation in the X chromosome known as RRM2P4.

It is rare in Africa and so it is probably of non-African origin or, belongs to some group that moved out of Africa with it (where it later disappeared) and passed it back into the modern human lineage (this is known as "introgression"),
So I decided to take a look at the data on RRM2P4, and came across a Table from [2] shown below:

RRM2P4 data
Table 1. Shows RRM2P4 sequence in different populations. From [2]

I was expecting American sequences to resemble Western Asian ones (after all that is where the Amerindians are supposed to have come from), but no. No similarity whatsoever.

The only Asian sequence that is identical to American ones, is from Pakistan.

So here we have a link between: Pakistan and America with an X chromosome mutation RRM2P4 and the previous one, another mutation in the X chromosome (B006) linking America and the same region of the Indian Subcontinent.
Two links that completely by-pass the rest of Asia that lies between Pakistan/India and America.

Both in an X chromosome, one which we all inherit from our female ancestors (if you are a man, your X chromosome is your mother's and your Y is your father's. If you are a woman, you got an X from your mom and another X from your Dad, but his came from his mom - your paternal grandmother).

So this means that these mutations introgressed into the human (H. sapiens) lineage from Female H. erectus or Neanderthals.

But is there any other linkage between both regions?

O blood allele, as I mentioned in my previous post has been linked to Neanderthals and, has its highest frequencies in America. Most of Western Asia has relatively low ratios of O allele, and B is predominant (you would expect the opposite if Asia was the cradle of Amerindians).

But, surprisingly, a study indicates that O blood group is higher in Sindh and Baluchistan (Southern Pakistan), see table below from [3]:

blood groups pakistan

And the data from [4] indicates that in eastern Pakistan, just above Sindh the percentage of O allele is even higher, as it ranges from 54& to 57.6% (Punjab, Gujrat and Wah Cant).

In India, the area just east of those mentioned in Pakistan, have a very strange blood group, the "O Bombay Blood Group", first discovered there, and found in about 1 every 17,600 persons in India.

It is found on the western coast of India and in Maharashtra, Gujrat (India) Karnataka, Goa and Andhra Pradesh.

So we have a higher percentage of O allele in this part of the world, and, a strange variety found only here!.

Sources:

[1] Yotova et al., (2011). An X-linked haplotype of Neandertal origin is present among all non-African populations 25.01.11.
[2] Michael F. Hammer, Daniel Garrigan, Elizabeth Wood, Jason A. Wilder, Zahra Mobasher, Abigail Bigham, James G. Krenz and Michael W. Nachman, (2004), Heterogeneous Patterns of Variation Among Multiple Human X-Linked Loci, The Possible Role of Diversity-Reducing Selection in Non-Africans.
doi: 10.1534/genetics.103.025361 Genetics August 1, 2004 vol. 167 no. 4 1841-1853
[3] Imranud Din Khattak, Taj Muhammad Khan, Purdil Khan, Syed Mukhtar Ali Shah, Sania Tanveer Khattak, Anwar Ali. (2008). J Ayub Med Coll Abbottabad 2008;20(4). Frequency of ABO and Rhesus blood groups om district Swat, Pakistan
[4] Mohammad Anees and Mohammad Shabir Mirza, (2005). Distribution of ABO and RH Blood Group Alleles in Gujrat Region of Punjab, Pakistan Proc. Pakistan AcaMd.. SAcnie.e s4 2&(4 M):.2 3S3ha-2b3ir8 M.2i0rz0a5


Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia
2011 International Year of Forests
2011 International Year of Forests Copyright 2009-2011 by Austin Whittall © 

Friday, September 16, 2011

Neanderthals in America some genetic proof

 
I have already written about the possible entry of Homo erectus into America and its colonization of the New World until the arrival of Modern humans some (45? to 15? thousand years ago [kya] - the actual date is still uncertain).

Today I will look into the possibility that our distant "relative", Neanderthal (or Neanderthal) colonized America long before modern humans appeared on scene. And it will back up a previous post on Neanderthals in America.

Neanderthals some background

Actually little is known about their origin. In fact, the human family tree is still being drawn. Each expert has his or her own theory and read the facts differently. After reading different articles and papers, I believe that we can outline the following "sketchy" timeline:

1. Homo erectus left Africa and settled in Asia about 1.8 Million years ago. Most of their fossils (and, by the way, very old ones) have been found in the Far East (China, Indonesia), but more recent ones (800,000 years old) have been unearthed in the Caucasus.
2. Europe's oldest fossils were found by Bermúdez de Castro in 1997, at Atapuerca, Spain, the Homo antecessor it is an "archaic" hominin, and differs from the mor primitive H. erectus. They date from 780 kya ago.
3. Then there is the Homo heidelbergensis found in Europe, where it lived 600 to 400 thousand years ago. This leads to some questions:
  • Did they originate in Europe from H. antecessor, and later moved back into Africa?
  • Did they originate in Africa and migrate to Europe, replacing H. antecessor?
4.In either case, we, modern humans (Homo Sapiens) and Neanderthal evolved from H. heidelbergensis .
5. The Neanderthal split about 300,000 years ago We do not know where they split. Modern Humans did so in Africa about 200,000 years ago.
6. Scientists do not know where Neanderthals evolved; there are several possibilities:
Did some African H. heidelbergensis migrate from Africa into Eurasia and evolve there into Neanderthal? or did the European H. heidelbergensis evolve there into Neanderthals?
The outcome was the same, Neanderthals lived outside of Africa and occupied a range which covered most of Southern Europe, the Middle East, Caucasus and the Iran, Afghanistan area. See map below.

Neanderthal homeland
Neanderthal homeland.

None lived in Africa. They were encountered by modern humans when our ancestors moved out of Africa and took over the world, condemning Neanderthals to extinction.

Did we mix with them?

Research published in early 2011 by Yotova et al. [1] which focused on a very small part of a gene which is found on the X chromosome and known as B006 haplotype has come up with some interesting conclusions:

We share B006 with Neanderthals. And it is clear from the map below (taken from [1]) that it is very common outside of Africa and, non-existent in Sub-Saharan Africa, which suggests that it comes from a non human gene pool. That is, some hominin living outside of Africa and that later passed on this haplotype to modern humans: Neanderthal.

B006 map
Worldwide distribution of B006 haplotype based on a worldwide sample of 6092 X chromosomes. From [1]

Notice that America has the highest prevalence of B006 in the whole world! (centered on Canada's west coast).

Let me qute Yotova:

" the evidence for Neandertal origin of B006 appears very strong. [...] Outside Africa, B006 is found in all habitable continents including Australia, as determined from a remote community of isolated indigenous Australians living in Central Australia [...] The ubiquity of B006 lineage reflects a worldwide contribution of Neandertal lineages to non-African genomes. It indicates very early Neandertal admixture prior to successful range expansion of the population ancestral to virtually all contemporary non-African populations" [1]

A previous paper (Zietkiewicz, Yotova - 2003) [2] on B006, stated that "this lineage could have left Africa before the expansion (as early as 160,000 years ago) and admixed, outside of Africa, with the expanding [human] lineage".
The map included in that paper is interesting, and I include it below, and as you can see it repeats the same pattern as the map above but, adds some interesting data:

more B006
B006 distribution map. From [2]

"Different colors, if present, indicate different Tn alleles shared by the same B haplotype."[2]

The map shows that America and Europe share the same Tn allele (in green in the map), which according to Table 1 in [2], is T16 (out of the 74 cases of this T16 allele, 47 appeared in America, 14 in Europe, 10 in Asia and 3 in Africa. It is predominantly American. On the other hand, the other allele (T15) did not appear in America at all.

Notice how the "green" T allele in the Old World is concentrated in the Neanderthal homeland!

But, believing in the "out of Africa" theory and the relatively recent population of America, the authors of paper [2] however disregarded American data in their analysis: "(disregarding the exceptionally low S2 value of 0.2 in the Americas)." The formula they use in their calculations was:

E(s2) = ge x μ

Where ge is the number of generations (at approx. 25 years per generation) since the population began to expand rapidly and, μ is the rate of mutation, and s2 is the standard deviation.

They took the mutation rate μ=2.3×10-5 and "estimated the time of the non-African lineage expansion (ge from eq. [5]) to be 4,040–4,260 generations, or 101–107 kya." [2] . That is, the time since humans emerged from Africa.

The same formula, applied to America gives: 188 kya!! Nearly 190,000 years. In other words, The lineage had all that time to evolve in America.

Discussion no the meaning of this. Lets highlight the main points:
  • The highest frequency of B006 occurrence is not in Neanderthal's homeland (Map 1) but in America : 25% approx. prevalence in America vs. 10% approx in Europe.
  • B006 has two Tn alleles. One of them, T16 is found in America: almost exclusively there, with 64% of the world's T16. That is followed by 19% in Europe, and the rest in Asia (14%) and Africa (of American Origin or Arabe Slave trade). T15, the other allele is not found in America, it is mostly (88%) Asian.
  • So there is clearly a Europe-America link and, as T15 is not found in America and it is very common in the supposed homeland of Amerindians (Asia), there is a clear Asia - America "gap" or disconnection.

Devil advocate: Orthodox science explains the loss of the predominant B haplotypes found in Eurasia and the increase of B006 as follows:
"However, the loss of two haplotypes frequent in Eurasia (18.8 and 7%) and the rise in frequency of a third haplotype rare elsewhere, indicate a major population bottleneck in the peopling of the Americas. Although genetic drift appears to have played a greater role in the genetic differentiation of Native Americans than in the latitudinally distributed Eurasians" [3]

In other words the cause is either :
  • A "founder effect" is the cause: a small group of Asians entered America and so they had a limited "gene pool" to begin with, all other Amerindians derive from this small group.
  • or "population bottleneck" : a large diversified population is drasticall reduced (illness, famine, etc.) and the few that survive, and repeople the region, have a limited or restricted gene pool

We side with an opposite point of view which can be supported with the previous data:

Neanderthal had the B006 T16 lineage, and wandered into Asia, well beyond his European-Levantine homeland. There, he crossed into America, perhaps finding Eastern Asia unfriendly or already peopled with H. erectus.
America was empty, unpeopled so they expanded into a new continent free from competing hominids.

But we have evidence from another source, Blood, Amerindians and Neanderthals have a very high frequency of O blood group:

Neanderthal blood groups.

The blood of two Neanderthal individuals has been analyzed and found to belong to the O blood group. So it dates back at least to their days, and it may even be much older: "The results however suggest the presence of the human O01 allele already in the common ancestor of Neandertals and modern humans and thereby confirming an emergence of the O01 allele more than 1 Mya predating the divergence of the modern human and Neandertal populations".

Furthermore, they concluded that there was " a potential selective advantage of the O allele" [4] within the Neanderthals, meaning that it was a very common blood group in that population.

Unsurprisingly, Amerindians belong, almost exclusively to the O group (85.5% in North America and 90.9% in South America vs. a global average of 69.2% ). A group of Neanderthals migrating to America would have taken their O group with them.

"All major ABO blood alleles are found in most populations worldwide, whereas the majority of Native Americans are nearly exclusively in the O group [...] in all American populations, the same set of haplotypes O1, O1v, and O1v(G542A) was present" [5]

The authors believe that this is due to a founding population effect and suggest that the O1v(G542A) mutation found only in Amerindians, "could have emerged in Beringia, probably during the differentiation process of Asian lineages that gave rise to the founding population of the [American] continent"[5]

Ahh, the out of Asia and into Americas theory is so ingrained! please le me point out that: (O1v(G542A)), have not been found in Asians, suggesting an Ameri can origin of the allele or, perhaps a Neanderthal (pre-h. sapiens) origin.
It is interesting to point out that O blood allele appears in a large quantity of variations, this must clearly indicate that it evolved selectively and diversified, lets read about this diversity:

"Far from being monomorphic, at the sequence levels Native Americans present a variety of O haplotypes, some isolated geographically (such as O05 and Ov7 in the Cayapa, O32 and O33 in the Aymara), some shared with other human populations (O1 and O1v), and one haplotype called “O1v542” which has been found in all Native American populations screened at this level (Nahua, Mazahua, Maya, Mexican Mestizo, Cayapa, Aymara) and may very well be unique to the Americas (Estrada-Mena et al., 2009). [6]

The alleged "cradle" of Amerindians, Asia, is the highest in the world for type B blood allele (America is the lowest - and mainly in Western Alaska). Furthermore it is the rarest blood allele (only 16% of mankind has it).

Closing comments
Perhaps more research and field activities will unearth Neanderthal remains in America or, as genetic studies advance, they will provide more evidence and let us settle this issue.

Sources

[1] Yotova et al., (2011). An X-linked haplotype of Neandertal origin is present among all non-African populations 25.01.11. You can read it here:
http://operatorchan.org/z/src/molbev.msr024.full.pdf
[2] Ewa Zietkiewicz, Vania Yotova, Dominik Gehl, et al. (2003), Haplotypes in the Dystrophin DNA Segment Point to a Mosaic Origin of Modern Human Diversity Am J Hum Genet. 2003 November; 73(5): 994–1015. Published online 2003 September 25.
[3] Bourgeois, S., Yotova, V., Wang, S., Bourtoumieu, S., Moreau, C., Michalski, R., Moisan, J.-P., Hill, K., Hurtado, A. M., Ruiz-Linares, A. and Labuda, D. (2009), X-chromosome lineages and the settlement of the Americas. American Journal of Physical Anthropology, 140: 417–428. doi: 10.1002/ajpa.2108
[4] Carles Lalueza-Fox, Elena Gigli, Marco de la Rasilla, Javier Fortea, Antonio Rosas, Jaume Bertranpetit and Johannes Krause, (2008) Genetic characterization of the ABO blood group in Neandertals BMC Evolutionary Biology 2008, 8:342
[5] Benito Estrada-Mena, F. Javier Estrada, Raúl Ulloa-Arvizu, Miriam Guido, Rocío Méndez, Ramón Coral, Thelma Canto, Julio Granados, Rodrigo Rubí-Castellanos, Héctor Rangel-Villalobos, Alejandro García-Carrancá, (2009). Blood Group O Alleles In Native Americans: Implications In The Peopling Of The Americas. American Journal of Physical Anthropology; 142(1): 85 - 94
[6] Fernando Villasnea, (2010). Evolution of the ABO Blood group locus in Pre-Columbian Native Americans.


Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia
2011 International Year of Forests
2011 International Year of Forests Copyright 2009-2011 by Austin Whittall © 

Thursday, September 15, 2011

Nahuelito in Google Earth?

 
nahuelito
Odd shape in Lake Nahuel Huapi. Google Earth

Above is a screenshot from Google Earth. The coordinates of the white blob inside the red circle are given in the image. It is a spot in the middle of the lake, between Huemul Peninsula and San Pedro Peninsula, just east of Victoria Island.

It is about 8 m (25 ft.) long and big enough to appear in the satellite photograph.

What is it? Jokingly I could say it is Nahuelito. But it is more likely a train of waves which, in that part of the lake can be quite big on a windy day. Frothy rolling waves may appear on a satellite image. However the shape is odd. Could it be a boat? (not too clear an image to let us decide if it is or it isn't). It could also be a burst of bubbles issuing from the fault that lies below, on the lake's bed (see my post Bubbles and Nahuelito).


Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia
2011 International Year of Forests
2011 International Year of Forests Copyright 2009-2011 by Austin Whittall ©