(Yet) More New Insights Into Our Evolutionary History
The analysis of genome-wide patterns of variation in human populations can provide genetic evidence of patterns of human migration and adaptation across the world. Two contrasting papers in this issue illustrate the power of the method. By combining a large number of datasets, Lohmueller et al. obtain precise estimates of the number of deleterious mutations carried by each of 15 African-Americans and 20 European-Americans, resequenced across 11,000 genes. They find that individuals with a European background have more potentially damaging mutations lurking in their genomes than those with an African background. This is interpreted as a genetic legacy from the 'out-of-Africa' bottleneck that accompanied the peopling of Europe. Jakobsson et al. take a broader snapshot of human variation by examining 29 populations in the Human Genome Diversity Project. They obtain genotype data for over 500,000 markers in the human genome. Echoing the study of Americans with African and European backgrounds, these data reveal increasing linkage disequilibrium with increasing geographic distance from Africa.
It's amazing to see how quickly the pieces of our evolutionary history are beginning to be put into place. And the more we understand how we arrived at where we are, the more likely we will be able to move forward to create a world with less disease and disadvantage.