Dobzhansky examined the genetic diversity of wild populations and showed that, contrary to the assumptions of the population geneticists, these populations had large amounts of genetic diversity, with marked differences between sub-populations.
Dobzhansky je proučavao genetsku raznolikost divljih populacija i pokazao kako te populacije, suprotno pretpostavkama populacijskih genetičara, imaju veće količine genetske raznolikosti s oznaćenim razlikama među subpopulacijama.