Asian backflow into Africa

Asians returned to Africa or, at least that is what this paper says: Brief communication: mtDNA variation in North Cameroon: Lack of asian lineages and implications for back migration from Asia to sub‐Saharan Africa, by Valentina Coia Giovanni Destro‐Bisol Fabio Verginelli Cinzia Battaggia Ilaria Boschi Fulvio Cruciani Gabriella Spedini David Comas Francesc Calafell, first published: 13 May 2005, https://doi.org/10.1002/ajpa.20138.

The abstract is very clear:

"The hypervariable region‐1 and four nucleotide positions (10400, 10873, 12308, and 12705) of the coding region of mitochondrial DNA (mtDNA) were analyzed in 441 individuals belonging to eight populations (Daba, Fali, Fulbe, Mandara, Uldeme, Podokwo, Tali, and Tupuri) from North Cameroon and four populations (Bakaka, Bassa, Bamileke, and Ewondo) from South Cameroon. All mtDNAs were assigned to five haplogroups: three sub‐Saharan (L1, L2, and L3), one northern African (U6), and one European (U5). Our results contrast with the observed high frequencies of a Y‐chromosome haplogroup of probable Asian origin (R1*‐M173) in North Cameroon. As a first step toward a better understanding of the evident discrepancy between mtDNA and Y‐chromosome data, we propose two contrasting scenarios. The first one, here termed “migration and asymmetric admixture,” implies a back migration from Asia to North Cameroon of a population group carrying the haplotype R1*‐M173 at high frequency, and an admixture process restricted to migrant males. The second scenario, on the other hand, temed “divergent drift,” implies that modern populations of North Cameroon originated from a small population group which migrated from Asia to Africa and in which, through genetic drift, Y‐chromosome haplotype R1*‐M173 became predominant, whereas the Asian mtDNA haplogroups were lost."

In plain English, there is an Asian Y-chromosome haplogroup in North Cameroon, in equatorial Africa and the authors can't quite fit it into the Out of Africa theory because it is a male lineage and there are no Asian mtDNA groups in the region...

Did a band of men from Asia move across Africa to Cameroon without women? leaving their Y-chromosome DNA but no mtDNA... Or did genetic drift erase the invading group's women's mtDNA?. Why would this happen?

I think that the U haplogroup mtDNA is the key here... see the map below:

The map shows mtDNA haplo U distribution. Clearly an "into Africa" move.

This surely introgressed Neandertal DNA into Africans.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2018 by Austin Whittall © 

On some misconceptions regarding mutations and "antiquity"

This website in an attempt to explain DNA diversity that allows us to identify "older" genomes from more "recent" ones, says the following:

"There are parts of your (our) genome where random mutations won’t generally kill you. Random mutations tend, therefore, to accumulate there. Since have some pretty decent estimates for how often random mutations occur, comparing the mutations in two different populations lets us estimate how long ago they split. For example, let’s suppose you get one random mutation per hundred years, and we’re comparing two populations that split 300 years ago and haven’t seen each other since. Population A should have gotten 3 mutations during that 300 years, and Population B should have gotten 3 mutations. So if we look at a third population, C, and find that they have 5 mutations that they don’t share with A or B, then we conclude that C split off from some ancestral population 500 years ago. We can reconstruct this as: 600 years ago, there was a group called ABC, but 500 years ago, it split into Group AB and Group C. 300 years ago, Group AB split into Group A and Group B."

Sounds great, so clear, so logical... but... This is a typical explanation for diversity in Africa vs. out of Africa and to put it bluntly, it is Wrong!!. And this is why:

It says there was an ancestral group, ABC which split 500 years ago into AB and C. Since the split, group C accumulated 5 mutations. And group AB split 300 years ago. Each sub group, A and B, accumulated 3 mutations each, which made them different. So as C has 5 mutations but A and B only 3 each, C is "older" than A or B. Did you see the mistake in this logical explanation?

The error is that although they postulate a random mutation every 100 years, the group AB which split from ABC 500 years ago did not accumulate any mutations from then until the split of A and B 300 years ago.

AB group did not accumulate a single mutation over 200 years, but C did, it added 2.

Then, A split from B, and both of them kept on mutating at 1 mutation every hundred years. Final score: C = 5 mutations and A & B only 3.

Actualy AB would have accumulated mutations over those 200 years, different mjtations from those of C. In fact all groups A, B and C would have accumulated 5 mutations over those 500 years.

All humans are equally ancient, we all carry the original DNA, and after we split into separate groups, our random mutations led us to split apart a bit more, but we all have roughly the same amount of mutations, unless, of course these mutations are not random, but are mobilized by selection, but that will be discussed in another post.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2018 by Austin Whittall © 

A great blog: thefuzzysasquatch

A quick post. I was reading about Homo erectus and came across this very interesting blog: thefuzzysasquatch. You can follow this link to visit it: http://thefuzzysasquatch.blogspot.com. It is written by NeilB.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2018 by Austin Whittall © 

On the direction and root of phylogenetic trees

When I see a phylogenetic tree (also known as an evolutionary tree), I always wonder why do we believe that those branches, trunk and the root which anchors it, are correct. I ask myself why is it assumed that the mutation took place in one direction and not the other. And this trivial question is fundamental because the branches open up from other branches based on the differences between the DNA as you move along them.

Below is a very simple example of what I mean. Imagine we reach a planet, and come across a species whose DNA is sequenced and reveals the folowing genes: A, B and C.

We then take a sample of individuals, and sequence their genome. The nine individuals in our sample come from different continents and the "order" of the genes is different in each individual:

AAAAA, AACAA, BAAAA, BAAAB, BBAAA, CACAA, AACAB, BAACB and BABAB.

We assume that mutations take place at random so a B can spontaneously mutate into C or A, an A into B or C and a C into A or B. So, a group of scientists after looking at the genomes assumes that AAAAA is the oldest group of that species and that the other populations are the result of mutations that modified the original genome. They build tree (1) shown below. The most distant population is the one with the BABAB genome.

The red arrow marks the "founding" population and the green arrow the "newest" group, descended from them.

But another group of scientist based on some ancient remains and other assumptions, says "No, the original population is not AAAAA, it is the people carrying the BABAB genes" (exactly the opposite to what the first group of scientists have proposed and proven in Tree (1).

The second group builds Tree 2, where as we can see (the green arrow shows the original population and the red one shows us where they place the population AAAAA. For this second group of scholars, populations AACAB and CACAA are the "most recent" populations. The tree below shows the mutated gene in red:

Two different trees built from the same genome samples. Copyright © 2018 by Austin Whittall

The scholars could then identify haplogroups where the A to C or the B to A mutation marks a haplogroup and theorize on how these haplogroups evolved one from the other... Does this sound familiar? Yes, it is how the mtDNA and the Y chromosome DNA haplogroups were created -by adopting certain mutations as key indicators for branches and defining that it took place in a certain way (in our DNA, for instance, an aadenine (A) switch for a cytosine (C) may mark a haplogroup. A for C but, we could also -as in our thoretical planet imagine that the C switched for an A and that the supposed parent genome is actually the child and not the other way round.

Thus the "new" American genomes could actually be the oldest and the African ones the youngest (like switching from tree 1 to 2 above).

This is of course an oversimplification, but we do have the DNA of Neanderthals, Denisovans, Homo sapiens from different sites around the world, and anchors from our ape relatives, the chimps. But often, when I look at the sequences (CGACGGAATACG... and so on - see this image below (from Nature where a standard human sequence -top row "Reference"- is compared to Neandertal sequences in the bottom two rows), I wonder how true and accurate are our "reconstructions". Which base mutated first, which later?...

And also See this image, which compares Denisovan, Neandertal and some apes and monkeys.

Trees are created by computer programs that use "assumptions" and theoretical considerations built into them by the scientists that programmed them. They supposedly work using statistically sound calculations, which are so complex that I doubt anyone can verify them without the help of computer software... so maybe some bias is built into them, for instance assuming that AAAAA is the "original" genome in our distant planet, or here, assuming that the DNA of an African is "older" than that of an Amerindian...

I don't believe in snake oil, but I do believe that we should look at facts with open eyes (like the two trees that can be built using those nine sequences in our distant planet. Same data different conclusions) and not be biased by a prejudice (prejudice = Pre Judgement, we use the data to prove what we believe to be true, not to prove the facts...).

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2014 by Austin Whittall © 

African diversity is the result of admixture with archaic hominids

African diversity is very likely the outcome of admixture with archaic hominids in Africa and not the result of Homo sapiens having originated in Africa.

In my post "Into Africa: sub-Saharan genetic diversity is due to introgression with archaics", I shared some papers "on the subject of the admixture of Homo sapiens and archaic hominins in Africa, which may be the cause of the "genetic diversity" which is the main evidence supporting an African origin of modern humans".

Today I read a very interesting paper: Recovering signals of ghost archaic admixture in the genomes of present-day Africans by Arun Durvasula and Sriram Sankararaman, doi: https://doi.org/10.1101/285734, which deals with an archaic admixture into the West African Yoruba people.

The paper states: "Our results suggest that Yoruban individuals trace about 7.9% of their genomes to an as yet unidentified archaic population. This is in agreement with some results from previous papers in other African populations such as the Biaka and the Baka, suggesting that there was a rich diversity of hominin species within Africa and that introgression was commonplace".

The authors discard a Neanderthal origin for this archaic DNA: ". It is plausible that this archaic ancestry is, at least partly, the result of Neanderthal introgression into the Yoruba mediated by more recent west Eurasian gene flow into Yoruba [10]. However, the proportion of Neanderthal ancestry in Yoruba is very small (about 2 × 10−4) so that we would not expect this small proportion to explain our signal".

Furthermore, they report that ", it is unclear whether the archaic signatures found here are from the same as those found in other African populations" which means that we could expect many admixture events in Africa between H. sapiens and archaics.

These introgression events are, in my opinion, the source of the great genetic diversity found in Africa. Diversity which is used to support an African origin of modern humans. The logic is the following: out of the great genetic diversity in Africa only part of it went into the rest of the world due to the small size of migrating populations, then bottlenecks reduced this diversity even more. Conclusion the higher African genetic diversity is proof of their ancestral position to all other humans.

But what if... H. sapiens originated in Asia (from H. erectus stock) and re-entered Africa, mixing there in the ancestral homeland with achaic hominids? The outcome would be an input of archaic genes into African H. sapiens causing them to have a greater genetic diversity. But in this case the cradle of mankind would be Asia and not Africa.

And that is what I posted here: "This leads me to ask, what if African heterozygosity was enriched by recent admixture with other hominins in Africa? an inflow of different relic alleles elevated African diversity above that of non-Africans. Could current lower Amerindian heterozygosity reflect an ancient population just like that of Denisovans or Neanderthals?".

Surely more papers will explore this "ghost" signal among Africans and clarify the matter.

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2018 by Austin Whittall © 

Update Paracas "elongated skulls" (not Alien but Siberian)

This article: "Russian origin of Peruvian elongated skulls?" by Will Hart, concludes that "the skulls probably originated in the Altai region of southern Siberia" it cites his investigations with Brien Foerster.

The article is interesting, but I disagree with the following point:

"There are other controversial issues that the Paracas skulls have raised. Without a doubt the individuals that had these skulls were not members of any native tribe. No Peruvian groups have red hair. We have also analyzed the results of ABO blood group studies and found they have blood groups A and B.
The Inca and other tribes were 100% type O+ positive, a fact that has long been known by anthropologists. They simple do not the prevailing theory and so have been dismissed for decades as genetic anomalies."

Because, there also are A blood group mummies in Peru according to: Am J Phys Anthropol. 1978 Jul;49(1):139-42. ABO blood groups in Chilean and Peruvian mummies. II. Results of agglutination-inhibition technique. by Allison MJ, Hossaini AA, Munizaga J, Fung R.

So it is not a 100% O blood group region.

The article mentions Huns, Denisovans and the fact that Paracas skulls have red hair (do they or is it merely bleaching as time goes by? or probably other factors... read this article for more on the hair of Paracas mummies (from www.livescience.com) - the hair in the photos looks dark or even black to me.

Furthermore, head binding was practiced not only by huns and Paracas people, it was quite common all over the globe: in Asia, Australia, Africa and also in other parts of America (see this great article with photos).

At least Hart and Foerster don't believe that these are alien skulls!

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Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2018 by Austin Whittall ©