Razib Khan One-stop-shopping for all of my content

July 20, 2011

Who knows heritability and what do they know

Filed under: 2011 Survey,Blog,Survey — Razib Khan @ 6:04 pm

Heritability is a fraught topic. It comes up repeatedly on this weblog, but even long time readers can be confused as to its implications, as evidenced by the incorrect inferences made from their own understanding of the concept. The most common problem is that too often people think that heritability is just a scienced up version of the colloquial idea of some traits being “more genetic” or “less genetic.” It’s not that at all. Traits totally specified in their details by genetic pathways can be non-heritable. That’s because heritability looks at the association between parents and offspring on a trait and attempts to separate the population-wide proportion of the variation attributable to genes and not attributable to genes. When you have a genetically specified trait, like the number of human fingers, you have no real variation within the population to work with (with some rare exceptions). It doesn’t make sense to talk about the heritability of the number of fingers, because this is a fixed trait in the human species.

In contrast, height is a perfect trait to illustrate heritability. Unlike behavioral or cognitive traits its measurement is clear, ...

Powered by WordPress