"It is clear that the nature of natural populations is a very complicated subject, and it now appears probable that adaptation of the various genotypes to different ecological niches and frequency-dependent selection are at least as important, and probably more important in many cases, than simple heterosis (in the sense of increased viability or fecundity of the heterozygote)".
"Está claro que a natureza das poboacións naturais é un asunto moi complicado, e agora parece probable que a adaptación de varios xenotipos a diferentes nichos ecolóxicos e a selección dependente de frecuencia son polo menos tan importantes ou máis, que a simple heterose (no sentido de incremento de viabilidade ou fecundidade do heterocigoto)".