Why Doesn’t Evolution Get Rid of Ugly People?:
In a groundbreaking study, biologists at the University of Edinburgh in Scotland have figured out why, at least in one species: genes that are good for males are bad for females and, perhaps, vice versa.The scientists studied red deer, 3,559 of them from eight generations, living on Scotland’s Isle of Rum. They carefully noted each animal’s fitness, who mated with whom, how many offspring survived, which offspring mated and with what results. Bottom line: “male red deer with relatively high fitness fathered, on average, daughters with relatively low fitness,” Edinburgh’s Katharina Foerster and her colleagues conclude in tomorrow’s issue of the journal Nature. “Male red deer with a relatively high lifetime [fitness, which includes their reproductive success, the only thing evolution cares about] sired, on average, daughters with a relatively low [fitness].” The reverse also holds. Males that were relatively less successful in their reproductive success and fitness had daughters that were extra successful.
The reason is that any particular gene-based trait may have very different effects on males than in females. Extrapolating to humans (and oversimplifying, sorry) you might imagine that a particular shape of the nose or turn of the chin would look drop-dead hunky on a male, but horsey on a woman; dad got to mate because his looks attracted a female, but the result of their togetherness produced daughters whose pulchritude was less than obvious.