GENETICIST DAVID REICH DISCUSSES HOW MIGRATION SHAPED MODERN HUMAN POPULATIONS

DNA reveals we are all genetic mutts.

GENETICIST DAVID REICH DISCUSSES HOW MIGRATION SHAPED MODERN HUMAN POPULATIONS

Examination of ancient DNA can provide profound insights into human history, according to David Reich, a professor of genetics at Harvard Medical School. His talk at the Science Center on Wednesday, “A Tale of Two Subcontinents: The Parallel Prehistories of Europe and South Asia,” was drawn from his new book, “Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past,” showing what recent studies have revealed about the prehistory of Europe and southern Asia.

Reich “reshaped our understanding of human prehistory,” according to a New York Times profile last year, with the publication of DNA from the genomes of 938 ancient humans — more than all other research teams working in the field combined. This research, the story noted, has shed light on the spread of agriculture and the peopling of the planet.

Reich began his lecture by explaining how his work is done: With recent advances in DNA sequencing, it is now possible to extract sequences from humans who lived tens of thousands of years ago by grinding skeletal remains — specifically parts of the ear where much DNA is concentrated — into a powder to be examined.

“It’s similar to the introduction of microscopes,” Reich said. “We can now look at worlds that were never previously looked at. And when we look at ancient DNA from past worlds, the stories don’t conform to what we thought. The information that comes from sequencing the whole genome makes it possible to answer questions that are profoundly different, and more precise than ever before.”

One phenomenon Reich set out to examine is the parallel histories of Europe and South Asia. Both regions saw the arrival of agriculture thousands of years ago, and they speak related Indo-European languages that eventually arrived in both regions. In both cases, the transformations happened through migration.

In Europe, Reich said, farmers arrived from Anatolia thousands of years ago and mixed with the local hunter-gatherer population; this is the largest source of ancestry in Europeans today. A second, later migration from the Eurasian Steppe happened at roughly the time Stonehenge was built. “People [from the Steppes] took advantage of two powerful inventions: the wheel and the domestication of the horse,” said Reich. “They were able to exploit the grasslands of the Steppes in a way that hadn’t been done before.” The Steppe migration resulted in a 90 percent replacement of the population.

A similar prehistory occurred in the Iberian Peninsula where a third population, also arrived from the Steppes, joined the hunter-gather and farmer groups. In this case, DNA research shows that the third population was exclusively male: While only 40 percent of the population about 6,000 years ago comes from the Steppes, 100 percent of the Y chromosomes do.

In India, a migration after the Ice Age caused a blending of two ancestries, called Ancestral North Indian and Ancestral South Indian. “People in India today are a mixture of two different portions of these ancestral populations,” Reich said. Genetics also show that India’s caste system, previously thought to have developed under colonial rule, was in place thousands of years earlier.

One question genetics can’t answer, he said in response to an audience question, is exactly how population replacement happened. “In the case of Britain after 6,000 years ago,” he asked, “did new people come in and kill the old ones, or just crowd them out? We just don’t know. What genetic data does is provide facts about movements of people and changes in groups. We are not the experts to describe how that happened.”

One important takeaway from this study, he said, is that humans inherently derive from mixed ancestry. “No population is, or ever could be, pure,” he said. “Ancient DNA reveals that the mixing of groups extremely different from each other is a common feature of human nature. We do not live in unusual times; profound events have occurred in our past. We should learn and feel more connected from that.”

https://news.harvard.edu/gazette/story/2019/02/harvard-geneticist-no-populations-dna-is-pure/

Elon Musk Is Spreading Centuries-Old Racist Pseudo-Science.

Racist pseudo-science is making a comeback thanks to Elon Musk. Recently, the tech billionaire has been retweeting prominent race scientist adherents on his platform X (formally known as Twitter), spreading misinformation about racial minorities’ intelligence and physiology to his audience of 176.3 million followers—a dynamic my colleague Garrison Hayes analyzes in his latest video for Mother Jones. X, and before it Twitter, has a long-held reputation for being a breeding ground for white supremacy.

Dating as far back as the 2016 election, these extremists have used the app to sow seeds of misinformation and spread racism. Garrison zeroes in on a specific phenomenon: Musk is amplifying users who will incorporate cherry-picked data and misleading graphs into their argument as to why people of European descent are biologically superior. He shows how fringe accounts, like user @eyeslasho, experience a drastic jump in followers after Musk shares their tweets. The @eyeslasho account even thanked Musk for raising “awareness” in a thread last year. (Neither @eyeslasho nor Musk, via X, responded to Garrison’s request for an interview.) “People are almost more susceptible to simpler charts with race and IQ than they are to the really complicated stuff,” Will Stancil, a lawyer and research fellow at the Institute on Metropolitan Opportunity, told Garrison in a video interview. He added: “This is the most basic statistical error in the book: Correlation does not equal causation.”

In 2022, just one week after Musk purchased Twitter, the Center for Countering Digital Hate —an online civil rights group— found that racial slurs against Black people had increased three times the year’s average, with homophobic and transphobic epithets also seeing a significant uptick, according to the Associated Press. More than a year later, Musk made headlines once again for tweeting racist dog whistles in a potential attempt to “woo” a recently fired Tucker Carlson. But, his new shift into sharing tech-bro-friendly bigotry carries its own unique set of consequences. Garrison also talks to Dr. Sasha Gusev, a statistical geneticist and associate professor at Harvard Medical School, who points out that because this racism is seemingly backed by scientific fact, people often lack the language to call out its problematic nature.

“There’s a kind of fusion between old-school gutter racism that everyone can recognize and this new-school Silicon Valley, data-driven analysis. And I think that this is very confusing to people,” said Gusev. “They don’t know what to do with it. They say, ‘Hey, there’s this thing that I recognize as ugly, and then there’s somebody posting a hundred charts that seem to support it.'”

https://youtu.be/U-uyndFrXeM

When DNA Evidence Challenges Ideas of A Person’s Racial Purity, White Supremacists Use a Decision Tree to Affirm or Discount the Results.

Now that science can determine a person’s racial and ethnic origins from a cheek swab, those devoted to ideas of racial “purity,” are employing methods of mind games and logic twists to support their beliefs despite facing evidence of their own multiracial heritage.

Researchers Aaron Panofsky and Joan Donovan of UCLA looked at the way members of the white supremacist website Stormfront handled finding out the results of their DNA tests. Panofsky explained that due to the potential for conflict over their very identity, these test takers were often supported in several ways that, frankly, are obviously not true. “When a subject would take the genetic ancestry test (GAT), the results to this group were good or they were bad,” Panofsky said. “Sometimes it was a matter of ‘Well I thought I was Irish, but actually I’m Norwegian, so I’m still very white, hooray.’ But if the news was what these white supremacists would consider to be bad, defined as evidence of heritage from, for example, Middle Eastern peoples, this is where it would get interesting.”

The first method to maintain the idea of racial purity was simply to reject GAT as a basis of knowledge about an individual’s heritage. Trust in family history and records were deemed superior to “some test.”

Another way that white supremacists maintain their race identity in the face of an undesirable result was what the researchers call, “The mirror test.” Basically, if you look white and you don’t appear to be Jewish or black, then you’re not. After all, the mirror doesn’t lie. Of course, this would imply that the tests are not accurate.

So-called racial purists also say they don’t believe in the tests because there exists a Jewish conspiracy. Panofsky explained, “Some of these people have said, ‘Well you know 23 & Me is Jewish run and operated and they just simply can’t be trusted. They want to make white people doubt their heritage, so the tests just can’t be true!”

When the news, however is such that a person laments, they may be “only 71% Caucasian,” there are a number of racial ideologues on the sites who accept that their fellow members can’t help the fact that there is race-mixing in their family tree. Instead they’re embraced for being true to the fact that there is a majority of “white” in the bloodline. The clear irony seems to be lost on a group that prides itself on standards of racial so-called purity.

“You’d think that the members of this site would say, ‘Get out! We don’t want you,’” Panofsky said. “Instead, they find ways to support their community members and keep them as part of the group.”

https://www.asanet.org/when-dna-evidence-challenges-ideas-persons-racial-purity-white-supremacists-use-decision-tree-affirm/