Résumé
Prabhakar et al. ( Reports, 5 September 2008, p. 1346) argued that the conserved noncoding sequence HACNS1 has undergone positive selection and contributed to human adaptation. However, the pattern of substitution in HACNS1 is more consistent with the neutral process of biased gene conversion ( BGC). The reported human- specific gain of function is likely due to the accumulation of deleterious mutations driven by BGC, not positive selection.