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'Evolution Is a Sloppy Artist'

A few weeks ago, the Gene Expression blog's Razib Khan reviewed a paper in Molecular Biology and Evolution that suggested that Crohn's disease may be the result of a selective sweep driven by adaptation to nutrient deficiencies incurred by European farmers switching to a grain-based diet. While that paper focused on one gene, Khan says, there is now a paper in PLoS Genetics that explores the hypothesis that "some deleterious mutations have hitchhiked [within the human genome] to high frequency due to linkage to sites that have been under positive selection." The study's results, the authors write, provide evidence that "hitchhiking has influenced the frequency of linked deleterious mutations in humans, implying that the evolutionary dynamics of advantageous and deleterious mutations may often depend on one another." In other words, Khan says, "Evolution is a sloppy artist … [and] there are often downsides to adaptation." But the paper's conclusions are tentative, and there are other processes that are responsible for the preservation of deleterious alleles, he adds. The authors of this paper haven't found the answer to the question of deleterious alleles, but rather one piece of the puzzle.

The Scan

Billions for Antivirals

The US is putting $3.2 billion toward a program to develop antivirals to treat COVID-19 in its early stages, the Wall Street Journal reports.

NFT of the Web

Tim Berners-Lee, who developed the World Wide Web, is auctioning its original source code as a non-fungible token, Reuters reports.

23andMe on the Nasdaq

23andMe's shares rose more than 20 percent following its merger with a special purpose acquisition company, as GenomeWeb has reported.

Science Papers Present GWAS of Brain Structure, System for Controlled Gene Transfer

In Science this week: genome-wide association study ties variants to white matter stricture in the brain, and more.