domingo, 27 de fevereiro de 2011

Estraçalhando a genética darwinista

Science 18 February 2011: Vol. 331 no. 6019 pp. 920-924
DOI: 10.1126/science.1198878


Classic Selective Sweeps Were Rare in Recent Human Evolution

Ryan D. Hernandez1,*, Joanna L. Kelley1, Eyal Elyashiv2, S. Cord Melton1, Adam Auton3, Gilean McVean3,4, 1000 Genomes Project, Guy Sella2,†, and

Molly Przeworski1,5,6,†‡

+Author Affiliations

1Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA.

2Department of Ecology, Evolution and Behavior, Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel.

3Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK.

4Department of Statistics, University of Oxford, Oxford OX1 3TG, UK.

5Department of Ecology and Evolution, University of Chicago, Chicago, IL 60637, USA.

6Howard Hughes Medical Institute, University of Chicago, Chicago, IL 60637, USA.

+Author Notes

↵* Present address: Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94143, USA.

‡To whom correspondence should be addressed. E-mail:

↵† These authors contributed equally to this work.


Efforts to identify the genetic basis of human adaptations from polymorphism data have sought footprints of “classic selective sweeps” (in which a beneficial mutation arises and rapidly fixes in the population).Yet it remains unknown whether this form of natural selection was common in our evolution. We examined the evidence for classic sweeps in resequencing data from 179 human genomes. As expected under a recurrent-sweep model, we found that diversity levels decrease near exons and conserved noncoding regions. In contrast to expectation, however, the trough in diversity around human-specific amino acid substitutions is no more pronounced than around synonymous substitutions. Moreover, relative to the genome background, amino acid and putative regulatory sites are not significantly enriched in alleles that are highly differentiated between populations. These findings indicate that classic sweeps were not a dominant mode of human adaptation over the past ~250,000 years.



Se não foi esse o modo evolucionário, qual foi? Pode esperar sentado que os autores não disseram qual foi o modo alternativo que livrou a cara de Darwin. Pensar que este é o modelo utilizado para humanos e os demais organismos. Vai mudar?



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