The Neandertal pigmentation race

As regular readers know, I've been detailing some of our work on the pigmentation genes of Neandertal and Denisova genomes. I got interrupted in the middle of my posts on that work undertaken by my undergraduate students, but we've got some interesting results. I've got to get going faster writing them up here, because we now have some competition.

Traci Watson covers a new, short paper that infers pigmentation phenotypes for Neandertals, the Denisova genome, as well as several modern humans with whole-genome data: "Were Some Neandertals Brown-Eyed Girls?"

One complication is that traits such as hair color are controlled by multiple genes. To determine the cumulative impact of multiple genes on one trait, the authors assumed they could simply add together the impact of individual genes. The female Neandertal known as Vi33.26, for example, had seven genes for brown eyes, one for "not-brown" eyes, three for blue eyes, and four for "not-blue eyes." By the researchers' reckoning, that means a six-gene balance in favor of brown and a negative balance for blue, so Vi33.26's eyes were probably brown. According to this method, all three Neandertals had a dark complexion and brown eyes, and although one was red-haired, two sported brown locks.

I'm quoted very extensively in the article, and my basic attitude is that the new paper's results don't match what my students have found. So, time to continue my series!