Why the Y chromosome is coming back

Last week Spencer and I talked about chromosomes and their sociological import on The Insight. It was a pretty popular episode, but then again, my post on the genetics of Genghis Khan is literally my most popular piece of writing of all time which wasn’t distributed in a non-blog channel (hundreds of thousands of people have read it). Thanks to everyone who left a review on iTunes and Stitcher (well, a good review). We’re getting close to my goal of 100 reviews on iTunes and 10 on Stitcher so that I won’t pester you about it.

Of course the reality is that the heyday of  chromosomal population genetic studies was arguably about 15 years ago, when Spencer wrote The Journey of Man. I have personally constructed Y phylogenies before…but as you know from reading this weblog, I tend to look at genome-wide autosomal studies. There is a reason that why Who We Are and How We Got Here focuses on autosomal data.

All that being said, Y (and mtDNA) still have an important role to play in understanding the past: sociological dynamics. The podcast was mostly focused on star phylogenies, whether it be the Genghis Khan haplotype, or the dominant lineages of R1a and R1b. Strong reproductive skew does have genome-wide effects, but unless it’s polygyny as extreme as an elephant seal’s those effects are going to be more subtle than what you see in the Y and mtDNA.

Submitted for your approval, two recent preprints on bioRxiv: The role of matrilineality in shaping patterns of Y chromosome and mtDNA sequence variation in southwestern Angola and Cultural Innovations influence patterns of genetic diversity in Northwestern Amazonia. The future is going to be in understanding sexual dynamics and culture.

The Insight, Episode 23: Patrick Wyman, Barbarian Genetics

This week on The Insight we talk to Patrick Wyman of Tides of History. Patrick is now a professional podcaster for Wondery, but I got to know him originally through comments on this weblog. Patrick is a historian of Late Antiquity. We originally encountered each other in 2010 after I had just finished a period where I was originally interested in the topic of his professional study, and he was interested in paleogenetics.

As Patrick said before we began recording, this podcast was a long time in coming. More precisely, the time is right, and it will get more right. More and more preprints like Amorin et al.’s Understanding 6th-Century Barbarian Social Organization and Migration through Paleogenomics will be coming out in the next few years. Ancient DNA extraction is cheap enough now that it will be used to explore historical lacunae, for example, what happened in sub-Roman Britain?

To get a sense of the period that we talk about in this podcast, I would highly recommend first The Fall of Rome: And the End of Civilization. This is a materialist treatment whch makes clear how thoroughgoing the collapse of economic production was across much of the Roman world. Then, Peter Heather’s Empires and Barbarians: The Fall of Rome and the Birth of Europe, anticipates some of the work coming out of genetics. Heather at the time was making the case that many of the barbarian groups that entered the Roman Empire were in fact coherent ethno-cultural entities. That the period of the “folk wandering” were literally folk wanderings.

Finally, you can finish up with Chris Wickham’s The Inheritance of Rome: Illuminating the Dark Ages 400-1000.

As a complement, one might check out Hugh Kennedy’s two books on the early history of Islam, The Great Arab Conquests: How the Spread of Islam Changed the World We Live In and When Baghdad Ruled the Muslim World: The Rise and Fall of Islam’s Greatest Dynasty. Kennedy doesn’t present a revisionist view, but that’s OK. Sometimes you need the null model. Like neutral theory.

The Insight, Episode 19: Roberta Estes, the Golden State Killer, and forensic genetics

Last week Spencer & I took a break from The Insight. We’re at 71 iTunes ratings. I would appreciate it if readers of this weblog could help us make it to 100 (then I’ll stop pestering you). Also, we only have 5 reviews on Stitcher.

This week we’re talking to Roberta Estes about the arrest of the suspect in the “Golden State Killings”. We kind put this together really quickly since it seemed relevant, and Roberta, Spencer and I have some competency in this area (we’ve all been talking to science journalists). The biggest takeaway from our conversation is that we were a little surprised that it took this long to apply 21st century genomics to forensics.

When I first heard about the arrest I told my wife that it probably was due to a relative match on something like GEDMatch. After the media reported that it was a “new method” I dismissed my supposition because relative matches aren’t a new or novel thing. Well, it turned out that’s exactly what they were talking about!

A lot of the story here is how law enforcement snapped a bunch of pieces together that were out there. The horse has left the barn, and everyone is trying to figure out how to deal with it.

The Insight, episode 18: Lee Berger, H. naledi, and open science

On this week’s episode of The Insight (Stitcher and Google Play) we talk to Lee Berger, author of Almost Human and a  paleoanthropological revolutionary. Or, less sensationally Lee tells us his view on the practice and results of science in his field (which is literally in the field).

Like most scientists, Lee is passionate about his work, but unlike many, he’s really good at talking about it. That’s an important skill going forward because science is usually funded by the public or private foundations.

Here is the original paper on Homo naledi, Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa. This small hominin had a brain 30% the size of our own, and lived until at least (and likely later than) 200,000 years ago in southern Africa. At some point they’ll get DNA out of naledi. Lee’s current opinion based on morphology seems to be that this is a highly basal lineage. That is, it separated from the one group that led to anatomically modern humans 2 million years ago!

Also, if you haven’t, please give us 5 stars on iTunes/Stitcher! I know how many readers I have, and 59 ratings aren’t the limit of reach of my audience.

The Insight, episode 17: Stuart Ritchie, intelligence and genes

On this week’s episode of The Insight (Stitcher and Google Play) we talk to Stuart Ritchie, a postdoc in Ian Deary’s lab, about recent developments in cognition and genomics. There’s a reason that Deary gets some time in She Has Her Mother’s Laugh; his group is publishing some really interesting work.

Before we get to the good stuff, Stuart gives us a quick review of general intelligence and why it matters. If you want a book-length treatment then his own book should suffice, Intelligence: All That Matters. Richard Haier’s The Neuroscience of Intelligence goes a little more into the “wet biology” aspect of the brain if that is more your style.

There are two reasons I wanted us to have Stuart on the podcast.

First, psychometrics is not a field which was hit by the replication crisis. It’s a pretty robust and reliable discipline. Companies such as the Educational Testing Service (ETS) rely on the predictive power of the constructs in the field to sell their products. And yet most well-educated people don’t really know much about intelligence testing except that it has been “debunked” by the Mismeasure of Man.

Because people don’t understand the history of intelligence testing (i.e., it enabled the meritocracy by removing the importance of “polish” and “good breeding”) it’s easy for American graduate schools to do things like removing the GRE as a criterion on admissions. Privately some academics have told me that this will mostly result in increasing the importance of undergraduate education and pedigree (because anti-GRE sentiment has become connected to “social justice” I think it’s removal is a fait accompli).

Second, the field of cognitive genomics is moving through a major turning point. A publication like this in January, A combined analysis of genetically correlated traits identifies 187 loci and a role for neurogenesis and myelination in intelligence, is going to be superseded in months. I’m not speculating. I know this as a fact, and so do many others. Where will we be in two years?

Ray Kurzweil has many ideas, some of them interesting, some kooky, and some of them wrong. But one idea he’s promoted which I think is correct is humans are not good at modeling exponential rates of growth. The field of psychometric genomics is now moving into the steep phase of ascent, as sample sizes go well above 1 million, and some researchers shift from proxy characteristics such as education and delve into raw intelligence test scores. Most people “outside of the know” are about to smash into the concrete before they even know it’s coming up at them….

Reflecting on Journey of Man 15 years later

Journey of Man, Spencer Wells’ book and documentary, came out 15 years ago. To a great extent the impact of TV is such that one can argue it introduced genetic anthropology to a whole generation.

A lot has happened since then. On this week’s The Insight we review what’s happened since then, and how Spencer, who started out a conventional academic scientist, became a documentarian.

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