Now I'm hungry for Lucky Charms.
Genomic surveys in humans identify a large amount of recent positive selection. Using the 3.9-million HapMap SNP dataset, we found that selection has accelerated greatly during the last 40,000 years. We tested the null hypothesis that the observed age distribution of recent positively selected linkage blocks is consistent with a constant rate of adaptive substitution during human evolution. We show that a constant rate high enough to explain the number of recently selected variants would predict (i) site heterozygosity at least 10-fold lower than is observed in humans, (ii) a strong relationship of heterozygosity and local recombination rate, which is not observed in humans, (iii) an implausibly high number of adaptive substitutions between humans and chimpanzees, and (iv) nearly 100 times the observed number of high-frequency linkage disequilibrium blocks. Larger populations generate more new selected mutations, and we show the consistency of the observed data with the historical pattern of human population growth. We consider human demographic growth to be linked with past changes in human cultures and ecologies. Both processes have contributed to the extraordinarily rapid recent genetic evolution of our species.
Greg Nog: This is why my current diet is limited to sipping whisky while listening to Sultans Of Swing on repeat for a half an hour each day.
Leaving the farmers’ market every Saturday, I am filled with self-satisfaction. Not only have I managed to accomplish some food shopping (a tricky feat for busy people), but I also imagine that I have participated in the political project of “the food movement.” In this fantasy, the First Lady, Michael Pollan, and Mark Bittman regard me with approval. This zeal fades quickly as the fruit flies come to feast on the tomatoes that I never seem to eat fast enough, and as I cave after a long day and dig into an ice-cream bar made with unpronounceable ingredients. Guilt soon sets in. Again, I have failed to live up to the high standards of today’s food reformers, where we eat simply, locally, and organically. All the time.
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