Written by: Stephen Hsu
Primary Source: Information Processing
This morning I attended an excellent talk: Adaptive Evolution of Gene Expression (see paper and video below), by Hunter Fraser of Stanford.
His results support the hypothesis that non-coding regions of the genome play at least as large a role in evolution and heritable variation as protein coding genes.
From an information-theoretic perspective, it seems obvious that there is much more information in the whole genome than in the ~20k coding regions. Without the additional information, it would not be possible to produce diverse organisms such as flies, worms, fish, and humans from very similar sets of genes/proteins. Strangely, though, I’ve found most biologists to be overly focused on coding regions. Perhaps studies like this will finally modify this prior.
Gene expression drives local adaptation in humans
Hunter B. Fraser
Department of Biology, Stanford University, Stanford, CA, 94305.
The molecular basis of adaptation—and in particular the relative roles of protein-coding vs. gene expression changes—has long been the subject of speculation and debate. Recently, the genotyping of diverse human populations has led to the identification of many putative “local adaptations” that differ between populations. Here I show that these local adaptations are over 10-fold more likely to affect gene expression than amino acid sequence. In addition, a novel framework for identifying polygenic local adaptations detects recent positive selection on the expression levels of genes involved in UV radiation response, immune cell proliferation, and diabetes-related pathways. These results provide the first examples of polygenic gene expression adaptation in humans, as well as the first genome-scale support for the hypothesis that changes in gene expression have driven human adaptation.
This is video of a similar talk at Stanford.