summer musin'

So somehow, going over dominant vs recessive traits in L311 has gotten me thinking about mating, producing offspring, and love. Hear me out now. I swear this isn't a segue into talking about the genetic perfection that is Natalie Portman. Just because a trait is dominant does not mean that it is genetically "superior" or even the wild-type trait [the most common version of that trait in that species]. For instance, having black hair looks cool but has no real advantage over blonde hair. Except that having blonde hair means that you are a genetic defect. Just kidding--at least partially. No really, just kidding! Or another example of a dominant, but not superior or more common trait is polydactylism, having more than the "standard 5 digits." Apparently, there are a decent number of polydactyls (sounds like a dinosaur!) in the Himalayian region, but not much elsewhere. In fact, not only are dominant traits not necessarily more common, recessive traits cannot be bred out of existence, despite the findings of German "experts". So, if all the blondes in the world mated with Asians, perhaps the F1 generation (the first filial generation) would be mostly brunette, but the F2 generation (second filial generation, grandchildren of the blonde/black-haired crosses) would show a quarter of the population to be blonde. Depending on who mates who and how the odds work out, later generations could have even more blondes. This works because traits are determined by genes, and the gene for blonde hair never gets over-written by the black hair gene, only overridden for that generation. SO! This all made me wonder: why are some traits more common than others? If dominant/recessive status does not explain a trait's expression in a population, then what does? Natural selection is a good answer for fatal/life-altering traits, such as cystic fibrosis or hemophilia (Well, hemophilia used to play a large part in survival of the fittest. Probably not so much now). But what about having 5 fingers vs 6? Or being a normal-sized vs being a dwarf? I guess natural selection plays a role, albeit not as direct of a role as in cystic fibrosis, in superficial traits. I've never approached a hot dwarf. Or a giant. Or a girl with male-pattern baldness. Or a girl with webbed hands (I don't think). But then again, the romantic that I am, I wouldn't say that I'd NEVER hit on any of the above. What if Natalie Portman asked you to marry her but also revealed that she has 7 toes on the right foot and 6 on the left foot? ("So you see, THAT's why they cast Keira Knightley in Bend it Like Beckham instead of me.") Would you say no? Now the more astute of you may be thinking, "But that's still being superficial. The one toe just happens to be outweighed by the high cheekbones and slender figure." So I'll consider other examples. Sure, it'd be weird to date a 7 foot tall girl, but she could protect my skin on sunny days. No, seriously, if I made good friends with a dwarf, and feelings developed, so be it. No harm done. I swear I was not trying to be sacrilegious towards the science of genetics. Just some summer musin's I had.