Autism is traditionally considered as a severe disorder involving some combination of repetitive behavior and restricted interests, deficits in social reciprocity and language, and mental retardation. But there is a long tradition of counterpoint to such disabilities, in so-called savant skills in fields that range from mathematical calculation and memory to art and music (Heaton and Wallace 2004). In each case, autistic savant skills represent rare yet astounding enhancements of human ability, beyond imagining for most of us. Understanding the cognitive and neurodevelopmental bases of such skills holds the promise of better understanding the causes of autism and enhancing human mental abilities to beyond the norm, if not at least helping us remember where we left the keys. (more…)
The human haplotype map (HapMap) shows that human populations differ genetically and have been subject to strong, recent positive selection: selection ‘for’ particular genetic variants. Surprisingly, patterns of inferred selection vary markedly between the three human groups analyzed thus far, one Caucasian, one African, and one Asian (Voight et al. 2006). Ethnicity, and natural selection, may thus play stronger roles in diverse human traits, including genetic susceptibility to disease, than previously believed.
One ethnic group, famous for reasons including its high incidence of otherwise-rare diseases, is the Ashkenazi. The concentration of recessive diseases in this group has usually been attributed to founder events, but this interpretation has been challenged (more…)