The role of transgenerational epigenetic inheritance indiversification and speciation

Inheritance is crucial to the evolutionary process. Although most evolutionary biologists assume that inheritance occurs exclusively through changes in DNA base sequence, it has long been known that inheritance can also occur through epigenetic mechanisms, such as chromatin marking, maternal effects, parasite transmission, or learning. In recent years, the possibility that such transgenerational epigenetic inheritance mechanisms can mediate long-term evolutionary change has received increased attention. Here, we consider the potential contribution of transgenerational epigenetic inheritance in driving diversification and speciation. As we describe, a growing body of theoretical and empirical studies suggests that epigenetic inheritance can accelerate the likelihood that genetic change will occur and thereby facilitate speciation. Additionally, evolution and diversification can potentially unfold based solely upon inherited environmental or learned effects, completely independent of any changes in DNA base sequence. Generally, clarifying whether (and how) epigenetic inheritance promotes––or impedes––diversification and speciation remains a key frontier of evolutionary biology.