Agreed there--the genes themselves are beneficial, but having too many of them isn't. Or, at least, not in the evolutionary sense of "will you have more kids than everybody else". Autism might be beneficial because it increases the chance of innovation--but, because it also decreases the chance of reproduction, it needs to be kept to a low level within any given population, or the benefit vanishes. A few autistic people in a population are necessary if you are going to have the population at large benefiting from the genes associated with autism. Very much like your sickle-cell anemia example.
The presence of lots of different genes in the gene pool, including ones we don't think of as particularly useful now, is definitely a good thing for any species though. Genetic diversity gives us lots of different potential solutions to problems we haven't even faced yet. That's one of the reasons why eugenics is such bunk--they'd want to narrow the gene pool. Anybody who's studied biology knows that's a bad, bad idea.
24 Feb 2012, 9:32 am
