In December 2018 I wrote a post suggesting "An ancient American origin of Hepatitis B virus" (HBV), yesterday I came across fresh research into the origin of this virus, published on Oct. 7 in Science magazine (Arthur Kocher et al. Ten millennia of hepatitis B virus evolution. Science, 2021 DOI: 10.1126/science.abi5658. 🔒 ). It adds data to the subject.
Main conclusions
- Wasn't an Out of Africa Event ("There is no evidence indicating that HBV was present in the earliest humans as they spread out of Africa" and "Our findings challenge the view that current HBV diversity reflects early human dispersals out of Africa."
- Old lineage in America ("Furthermore, the virus was present in the Americas by about 9000 years ago, representing a lineage sister to the viral strains found in Eurasia that diverged about 20,000 years ago")
- American HBV is a distinct Sister Clade ("HBV genotypes typically found in Native Americans (genotypes F and H) represent a sister clade to the rest of worldwide HBV diversity (which we refer to as the Eurasian branch)")
An American origin?
As the American lineage is the oldest, and on a separate branch, with all other Eurasians on a separate branch, and NO early African root (Africans are on the Eurasian side of the tree), this is disquieting for those supporting an Out of Africa and into America migration of humans. How can they explain that the American HBV is the oldest? and not at all related to East Asian - Siberian variants? You would expect the Amerindian variant to be a branch of the Siberian or East Asian ones if HBV entered America from there.
The authors add that "HBV ... found in Native Americans ... represent a sister clade to the rest of worldwide HBV diversity... In particular, the monophyly of the American HBV branch, comprising all ancient genomes from the Americas dating back to as early as ~9 ka ... was highly supported" meaning the HBV in America is old, and monophyletic (they all descend from the same ancestor, which in this case is distinct from the Eurasian and rest-of-the-world linages). This is remarkable.
But the authors cautiously add a disclaimer: "However, deep nodes within the Eurasian branch were not well resolved, pointing to plausible alternative topologies in which some of the earliest Eurasian lineages would have diverged before the American branch" meaning that there may be some other Eurasians from which both American and Rest of the World clades diverged.
The image shows all the global variants, except American ones, on the upper branch. Notice that simian (Chimpanzee, Gorilla, Gibbon, and Orangutan) variants and the African E variant are on this part of the tree. On the bottom of the image are the American variants. A separate branch. I added the red star to mark the point where American and Rest Of The World clades split.
What is interesting is that if you climb the tree from the root, the branches fork as follows:
- Root
- American branch
- Eurasian-African branch
- Gibbon - Orangutan branch
- All non-American Humans
So the great apes of Asia (Orangutan and Gibbon) and Asian-European-African humans got HBV from a common ancestor that also infected Americans?
Who was this hominin living in the Southeast Asian jungles? Maybe Homo erectus? The dates along the tree can be taken cautiously because a scientist studying virus will take the accepted date for the arrival of modern humans in America and apply it to his or her research. If conventional science agrees that 15 Ky is the date, then the split between Rest of the World and Americans will be set at that date. In fact the tree shows that all American branches coalesce at 15.3 to 18.9 Ky.
So how can this be reconciled with the Out of Africa origin of mankind?
Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2021 by Austin Whittall ©
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