Haploid Superiority

Abstract
Given that we humans are diploid, we might be inclined to think that there are evolutionary advantages to having two copies of every gene versus one. Not so, says new research (Zeyl et al.) discussed by Greig and Travisano in their Perspective. The new work demonstrates in haploid and diploid yeast populations of varying sizes that haploids have a distinct adaptive advantage in larger populations, but that this advantage disappears once the population size decreases.