The heritability of a trait within a population is the proportion of observable differences in a trait between individuals within a population that is due to genetic differences. Factors including genetics, environment and random chance can all contribute to the variation between individuals in their observable characteristics (in their "phenotypes")...Heritability thus analyzes the relative contributions of differences in genetic and non-genetic factors to the total phenotypic variance in a population. For instance, some humans in a population are taller than others; heritability attempts to identify how much genetics are playing a role in part of the population being extra tall.
Over at Haldane's Sieve Dr. Joseph Pickrell has a commentary up on a preprint on explaining the 'missing heritability' using yeast genetics. All good reading. I long ago gave up on the idea that the idea of 'heritability' would ever be widely internalized among the educated public in any ...
