Transgenerational epigenetic inheritance: Prevalence, mechanisms, and implications for the study of heredity and evolution

This review describes new developments in the study of transgenerational epigenetic inheritance, a component of epigenetics. We start by examining the basic concepts of the field and the mechanisms that underlie epigenetic inheritance. We present a comprehensive review of transgenerational cellular epigenetic inheritance among different taxa in the form of a table, and discuss the data contained therein. The analysis of these data shows that epigenetic inheritance is ubiquitous and suggests lines of research that go beyond present approaches to the subject. We conclude by exploring some of the consequences of epigenetic inheritance for the study of evolution, while also pointing to the importance of recognizing and understanding epigenetic inheritance for practical and theoretical issues in biology. Definitions: Epigenetics and Epigenetic Inheritance EPIGENETICS has become one of thebuzz words of biology in recent years. Following the success of genome projects in defining what genomes are, the empha-sis has shifted to what they do, and there is renewed interest in understanding the epi-genetic processes of development. The term “epigenetics, ” however, has under-gone many transformations since its origi-nal definition by Waddington (see Wad-dington 1968 for a discussion), reflecting the changing foci of research in develop-mental molecular biology since the second half of the 20th century (Jablonka an