"Wit can stand its ground against Truth only a little while."

O titulo quotes Dr Johnson, que em geral tinha razao. Mas nem sempre, because after all, (segundo Tarantino) "That's the way it goes. But don't forget: It goes the other way too."




O meu candidato para presidente dos EUA, Chris Rock, disse algum tempo atras: "I bet there is no lactose intolerance in Rwanda." Agora Sarah Tishkoff e colaboradores na ultima edicao da Nature Genetics lhe dao razao. Segundo o resumo do artigo:

A SNP (single nucleotide polymorphism) in the gene encoding lactase (LCT) (C/T-13910) is associated with the ability to digest milk as adults (lactase persistence) in Europeans, but the genetic basis of lactase persistence in Africans was previously unknown. We conducted a genotype-phenotype association study in 470 Tanzanians, Kenyans and Sudanese and identified three SNPs (G/C-14010, T/G-13915 and C/G-13907) that are associated with lactase persistence and that have derived alleles that significantly enhance transcription from the LCT promoter in vitro. These SNPs originated on different haplotype backgrounds from the European C/T-13910 SNP and from each other. Genotyping across a 3-Mb region demonstrated haplotype homozygosity extending >2.0 Mb on chromosomes carrying C-14010, consistent with a selective sweep over the past 7,000 years. These data provide a marked example of convergent evolution due to strong selective pressure resulting from shared cultural traits—animal domestication and adult milk consumption.



Traduzindo para o portingles: while it may be true that adult mammals lose the ability to digest milk properly, em humanos, principalmente humanos com fome, adults have evolved at least three distinct mutations para aproveitarem seu milkshake, iogurte ou- numa pequena aldeia que resiste agora e sempre ao invasor- leite de cabra.