Post script to our wandering cousins (and their genetic streams)

Shortly after I posted about our wandering cousins, intrepid NYT science reporter Carl Zimmer posted story about a newly identified population called Ancient Paleo-Siberians:  https://www.nytimes.com/2019/06/05/science/native-americans-genetics-siberia.html?action=click&module=Well&pgtype=Homepage&section=Science.  The story is a lengthy one and I do not have the time to render it clearly here, but the gist is that geneticists looking at different populations in Siberia and in North America have found a complex story of migration, populations mixing, populations disappearing, etc.  By and large the current Siberians have little genetics in common with Siberians of the long past or with native Americans today.  Geneticists have found a group from 40,000 to 10,000 years ago that seem to have played some role in peopling the Americas called the Ancient Paleo-Siberians.  Current native Americans derive about 75% of their DNA from this group who have largely disappeared.

The geneticists and anthropologists and paleontologists are working on different explanations and wondering how to gather more data to resolve their differences. Very difficult to find fossils in that area, especially since after the last ice age the land bridge between Asia and North American is underwater and the rest is frozen.  But given the recent news stories I began to ponder the facts of populations arising and subsiding through multiple migrations back and forth.

In prehistoric times we are talking about changes over thousands of years; in modern times we are talking about days, months and a year or two.  The prejudices against breeding between groups may have lessened in some places but continues on in others, and I suspect that much of the reaction against migrants and refugees is more about sexual mixing than economic realities.   Immigrants contribute to social and economic vitality in short order, even making important contributions on many levels, so the complaints about them using resources etc. must be a smokescreen for other concerns, e.g., group racial identity.

Only problem there is that group racial identity is more a political instrument for gaining and consolidating power than a valid concern over any genetic differences which are at most miniscule.  So I wonder if Ancient Paleo-Siberians, Neandertals, Denisovans, Ancient North Siberians, Inuits and Mayans back in the day before their cultures established political structures and functions showed concerns over the influx of a new group.  Siberia to us seems rather forbidding but back in prehistoric times was a resource rich environment.  Plus there were just not that many people back then; the overcrowding we experience as normal was not known.  So long as hunting grounds were separate or even shared like the Native Americans did in our own valley here in SW Virginia, I doubt that many problems erupted.

Another pondering:  The story of Romeo and Juliet is iconic for the triumph and tragedy of love between groups. As our species evolved, when did emotional bonds and attachment surmount sexual attraction to become a dominant force in which the love between two people erased their concerns about group differences?  I think that was a great day in our history, even if different problems then arose.

One of the tropes characterizing modern times is the speed with which cultural change takes place, and I think that also applies to group mixing, whether ethnic or racial or cultural.  Groups adhere together only so long, whether it is a decade or a millennium, and then boundaries begin to blur and break down as they mix with another group. That seems to me a basic fact of life on Gaia.  Only physical isolation stops this process and even then not for long.

So when the nationalist cretins march to promote their own group’s solidarity (as they did in Charlottesville) and, by implication at least, superiority, I know that they are doomed to in-breeding catastrophes.  Indeed, they are already in-breeding catastrophes of the cultural sort.  Our hope is that humans continue as they have done since the dawn of our kind, wandering and meeting new people, learning and developing new ideas, and sharing the planet as best we can (which is better than we are doing now).  As always, travel on.

time to update timeline

A story on science news.com gives an accessible account of an article published in Science about a genetic study from the genome recovered from a boy who lived in southern Africa 2000 years ago:  https://www.sciencenews.org/article/ancient-boys-dna-pushes-back-date-earliest-humans.  The methodology here is way beyond my ken but it involves comparing this genome to others recovered all around Africa and Eurasia from different time periods and figuring out rates of genetic change that would account for its composition some 2000 years ago.  The scientists concluded that the essential genome for us, Homo sapiens, coalesced around 350,000 years ago; that is a 100,000 years earlier than previously thought.

Putting some of the reports together, it seems that humans in Africa long ago traveled the  length and breadth of the continent and intermarried for many thousands of years ago before modern humans migrated to Europe, maybe influenced by climate changes..  My 6/19/17 post was about a Moroccan fossil that also put Homo sapiens origin around 300,000 years ago.  For reference DNA studies indicate that Neandertals and Denisovans (our kinfolk in Europe and the Russian steppe;  homo sapiens did not arrive in Europe until around 30,000 years ago) split around 640,000 years ago.

Adding to a post from some time back check out these dates listed as years ago:

3 million—gene appears promoting brain enlargement

2 to 2.8 million—tools that were worked and shaped

1.8 million—fire and cooking (homo erectus)

before 640,000-Neandertal and Denisovan genomes took shape

500,000–phonological study’s estimate of origins of modern language

350,000-Homo sapiens genome took shape

130,000-eagle claw necklace from southern Africa

40,000 to 100,000—burials

45,000—paintings, good painting they are too

43,000—bone flutes

40,000—dogs domesticated

40,000—modern humans arrive in Europe

10,000—agriculture

9,000—dog burials (just found that one)

6,000—glyphs and a new learning curve

500–modern science took hold

And so we travel on.