The genetics of species differences

Trends Ecol Evol. 2001 Jul 1;16(7):343-350. doi: 10.1016/s0169-5347(01)02167-x.


Species are separated by reproductive isolation as well as by more 'ordinary' differences in morphology and behavior that play no necessary role in blocking gene flow. Although a great deal is now known about the genetics of reproductive isolation, we are only beginning to understand the genetic basis of ordinary phenotypic differences between species. I review what is known about the number of genes involved in such differences, as well as about the role of major genes and epistasis in the evolution of these differences. I also compare and contrast these findings with those on the genetics of reproductive isolation.