Internet dating for tall people
So please stop offering yourself as a counter-example of the trend (also, the key is to look within families, because the signal here is going to be swamped by other factors when you compare across populations). Height is a highly heritable trait where most of the variation within the population is due to variation as numerous genes.Third, a friend has sent me another paper which does confirm that even within sibling cohorts there does seem to be a correlation between height and I. The problem is that it is a very small one, so you need large data sets with a lot of power to see it. In other words, there isn’t a “tall” or “short” gene, but thousands and thousands of variants which shape the variation of the trait across the population.
How strong is sexual selection for intelligence and height?Model fits indicate that both pleiotropy and assortative mating contribute significantly and about equally to this genetic correlation.Pleiotropy here means that the same gene is impacting different traits (height and I. The additive genetic correlation between height and I. was 0.08 and 0.17 in males and females respectively.I have a suspicion that the “sweet spot” for mating is to be only somewhat smarter than than the average, but not so clever so as to be obnoxious.In the end I’d really like to see a massive number of siblings compared.Whenever people posit a pleiotropic relationship between traits I am always curious about the possibility that the traits may be correlated (or not) in siblings.
Population structure of some sort can produce correlations, but patterns within families are often more informative of the genuine genetic basis of these correlations.
In general estimates for the heritability of intelligence tend to be somewhat lower, on the order of ~50% rather than 80-90%.
It is due to the highly polygenic nature that both of these traits have been posited as candidates for a “good genes” model of sexual selection.
I think that’s doable with this data set, but I didn’t see it in the paper (tell me if I’ve missed something).
At some point we’ll have accurate high coverage whole genomes for many pairs, and we can ascertain whether it’s mutational load and pleiotropy more directly when it comes to correlations like this.
My own assumption is that something like this, perhaps with a mutational effect at the bottom of the distribution (due to large effect deleterious alleles knocking people down in height and intelligence), generates most of the correlation.