Hard sweeps and natural selection obscured by Bronze Age admixture
The above is the map from the Online Ancient Genome Repository. You can see the variation by region. There’s a lot of ancient DNA in Europe. Very little in Asia. And only moderate amounts elsewhere. The map is from a new preprint, Ancient human genomes reveal a hidden history of strong selection in Eurasia: The […]
Selection against height in Sardinians
Evidence of polygenic adaptation at height-associated loci in mainland Europeans and Sardinians: Adult height was one of the earliest putative examples of polygenic adaptation in human. By constructing polygenic height scores using effect sizes and frequencies from hundreds of genomic loci robustly associated with height, it was reported that Northern Europeans were genetically taller than […]
Inventing the whites, what hath fog wrought?
One of the first posts on this blog relating to archaeogenetics involved an essay by me involving reflections on the fact that a particular Y chromosomal haplogroup, N1c (N3a now), had a peculiar distribution which ranged from Siberia to Finland. The argument, at the time, was whether it was a lineage which moved east to […]
How your Neanderthal functions in the human genome
What does it mean that you have Neanderthal ancestry? Everyone agrees now that that ancestry exists, but does it make you any different from what you’d be otherwise? From a scientific perspective, one might ask what the function of Neanderthal genetic …
It’s raining selective sweeps
A week ago a very cool new preprint came out, Identifying loci under positive selection in complex population histories. It’s something that you can’t even imagine just ten years ago. The authors basically figure out ways to identify deviations of markers from expected allele frequency given a null neutral evolutionary model. The method is put […]
So merfolk are a real thing now: adaptation to diving
When Rasmus Nielsen presented preliminary work on diving adaptations a few years ago at ASHG I really didn’t know what to think. To be honest it seemed kind of crazy. Everyone was freaking out over it…and I guess I should have. But it just seemed so strange I couldn’t process it. High altitude adaptations, I […]
Natural selection in humans (OK, 375,000 British people)
The above figure is from Evidence of directional and stabilizing selection in contemporary humans. I’ll be entirely honest with you: I don’t read every UK Biobank paper, but I do read those where Peter Visscher is a co-author. It’s in PNAS, and a draft which is not open access. But it’s a pretty interesting […]
Selection for pigmentation in Khoisan?
In the recent paper, Reconstructing Prehistoric African Population Structure, there was a section natural selection. Since my post on the paper was already very long I didn’t address this dynamic. But now I want to highlight this section: The functional category that displays the most extreme allele frequency differentiation between present day San and ancient […]
So what’s point of demographic models which leave you scratching your head
There’s a new paper on Tibetan adaptation to high altitudes, Evolutionary history of Tibetans inferred from whole-genome sequencing. The focus of the paper is on the fact that more genes than have previously been analyzed seem to be the targets of natural selection. And I buy most of their analyses (not sure about the estimate […]
Buddy can you spare a selective sweep
The Pith: Natural selection comes in different flavors in its genetic constituents. Some of those constituents are more elusive than others. That makes “reading the label” a non-trivial activity.
As you may know when you look at patterns of…
Natural selection and dopamine receptor genes
Long time readers will be familiar with the large literature in behavior genetics/genomics and dopamine receptor genes. So with that, I point you to a paper exploring the patterns of variation and their relationship to possible natural selection, No Evidence for Strong Recent Positive Selection Favoring the 7 Repeat Allele of VNTR in the DRD4 […]
Why rice is so nice
The Pith: What makes rice nice in one varietal may not make it nice in another. Genetically that is….
Rice is edible and has high yields thanks to evolution. Specifically, the artificial selection processes which lead to domestication. The ̶…
The evolutionary effect of the sky gods
Last week I reviewed ideas about the effect of “exogenous shocks” to an ecosystem of creatures, and how it might reshape their evolutionary trajectory. These sorts of issues are well known in their generality. They have implications from th…
Natural selection in our time
Last month in Nature Reviews Genetics there was a paper, Measuring selection in contemporary human populations, which reviewed data from various surveys in an attempt to adduce the current trajectory of human evolution. The review didn’t find anything revolutionary, but it was interesting to see where we’re at. If you read this weblog you probably […]
Hybridization is like sex
One of the major issues which has loomed at the heart of biology since The Origin of Species is why species exist, as well as how species come about. Why isn’t there a perfect replicator which performs all the conversion of energy and matter into biomass on this planet? If there is a God the tree […]
Disease as a byproduct of adaptation
How we perceive nature and describe its shape are a matter of values and preferences. Nature does not take notice of our distinctions; they exist only as instruments which aid in our comprehension. I’ve brought this up in relation to issues such as categorization of recessive vs. dominant traits. The offspring of people of […]