Over at Nothing in Biology Makes Sense
, Chris Smith has been writing a series of posts digging deep into the evolutionary claims made in Nicholas Wade’s book A Troublesome Inheritance
. Last week, Chris debunked
the claim that human population genetics naturally sorts into “races”—this week, he’s taking on
Wade’s claim that variation at a particular gene has made some human populations more prone to violence than others:
Although some studies have found genetic variants in the MAO-A promoter region that are more common in some ethnic groups than in others (Sabol et al. 1998; Widom & Brzustowicz 2006; Reti et al. 2011) it is likely that these genetic variants are not –on their own– associated with violent or impulsive behavior (Caspi et al. 2002; Widom & Brzustowicz 2006). Instead, genetic variation in the MAO-A promoter seems to make some children less able to recover from abuse and childhood trauma, and therefore more likely to act out later in life (Caspi et al. 2002; Widom & Brzustowicz 2006). Simply carrying the ‘low expression’ allele in the MAO-A promoter does not have any effect at all on impulsivity or aggression.
Chris co-teaches a class on exactly the topics covered in A Troublesome Inheritance, so I highly recommend you read the whole thing, and follow the series to its conclusion.
This year at the Evolution meetings, for the very first time, the conference organizers offered presenters the option of having our talks filmed by graduate student volunteers. Naturally, I had to try this out—and the result isn’t half bad!
If only I’d pointed myself at the microphone more consistently. And said “umm” about three times less frequently. And maybe worn a nicer shirt …
I’ve written (another) review of Nicholas Wade’s “science of race” book A Troublesome Inheritance, this time for the Los Angeles Review of Books. If you’ve read the my previous review for The Molecular Ecologist, you won’t find much new here, but the LARB piece is pitched at a less technical audience, and takes a somewhat different point of entry:
CHARLES DARWIN is more usually cited for his scientific discoveries than his moral insights. In the closing pages of his travelogue The Voyage of the Beagle however, he condemns the practice of slavery — which he observed firsthand in the colonized New World — in blistering, heartfelt terms worthy of an Old Testament prophet
In this testimony against the great social sin of his age, Darwin makes an observation that should unsettle us even here and now: “if the misery of our poor be caused not by the laws of nature, but by our institutions, great is our sin.”
I’m extremely pleased for the chance to contribute to a great literary magazine, and I’m also quite happy to see that LARB went with my suggested, punny headline: “Cluster-struck.”◼
Over at The Molecular Ecologist I’ve done an in-depth review of the population genetics data cited by Nicholas Wade in his book A Troublesome Inheritance, which argues that social, cultural, and economic differences between human populations are all in our genes. Digging into the book’s endnotes, it didn’t take me long to find discrepancies between Wade’s description of basic population genetic results and the actual, um, results.
First and foremost, Wade claims that when population geneticists apply a class of statistical methods called clustering algorithms to datasets containing hundreds or thousands of genetic markers, they objectively identify five geographic groups that he calls “continental races”—differentiating African, European/Middle Eastern/South Asian, East Asian, Oceanian, and American people. What he does not make particularly clear is that while clustering methods do group genetic samples without direct instructions, the algorithms do not decide how many clusters there are. The geneticists using them do.
To make me feel somewhat better for having paid actual money to read this book, go read my whole review.◼
This week at Nothing in Biology Makes Sense!, guest contributor Daniela Vergara explains how CGRI, the initiative to sequence the genome-wide genetic variation of Cannabis, will answer cool evolutionary questions.
At the CGRI, we would like to understand first, how much genetic variation there is in the numerous pure C. sativa, C. indica, and C. ruderalis accessions and heirloom varieties. This will lead us to understand the relationships among the major lineages within the genus, the spread of Cannabis throughout the globe, and rates of historical hybridization between the named species.
For Daniela’s detailed run-down of important evolutionary questions in Cannabis, go read the whole thing.◼