Epigenetics and transgenerational transfer: a physiological perspective

Abstract

Summary Epigenetics, the transgenerational transfer of phenotypic characters without modification of gene sequence, is a burgeoning area of study in many disciplines of biology. However, the potential impact of this phenomenon on the physiology of animals is not yet broadly appreciated, in part because the phenomenon of epigenetics is not typically part of the design of physiological investigations. Still enigmatic and somewhat ill defined is the relationship between the overarching concept of epigenetics and interesting transgenerational phenomena (e.g. ‘maternal/parental effects’) that alter the physiological phenotype of subsequent generations. The lingering effect on subsequent generations of an initial environmental disturbance in parent animals can be profound, with genes continuing to be variously silenced or expressed without an associated change in gene sequence for many generations. Known epigenetic mechanisms involved in this phenomenon include chromatin remodeling (DNA methylation and histone modification), RNA-mediated modifications (non-coding RNA and microRNA), as well as other less well studied mechanisms such as self-sustaining loops and structural inheritance. In this review we: (1) discuss how the concepts of epigenetics and maternal effects both overlap with, and are distinct from, each other; (2) analyze examples of existing animal physiological studies based on these concepts; and (3) offer a construct by which to integrate these concepts into the design of future investigations in animal physiology.

Transgenerational seasonal timer for suppression of sexual morph production in the pea aphid, Acyrthosiphon pisum

“…Lees (1960) suggested that the seasonal timer would not result from a cytoplasmic substance which is diluted by cell division until it falls below a critical threshold, because the mechanism of the seasonal timer should resist many dilutions through several generations. Epigenetic mechanisms that alter the expression of DNA, however, can be passed on to one or more successive generations (Ho and Burggren, 2010;Sgrò et al, 2016). Although the role of epigenetic modification in reproductive polyphenism has not been studied, methylation levels in juvenile hormone associated genes are higher in winged asexual females than wingless asexual females in A. pisum (Walsh et al, 2010).…”

Cross tolerance in beet armyworm: long-term selection by cadmium broadens tolerance to other stressors

“…Irrespectively of its basis, the changes in the protective mechanisms level enhance survivorship chance of a population under stressing conditions (Ho and Burggren 2010;Hendry et al 2011;Feil and Fraga 2012). The experiment conducted on an unique isolated Cd-selected population of S. exigua gave us the opportunity to observe the changes under controlled conditions.…”

Physiological study of larval fishes: challenges and opportunities

“…Because gene expression ultimately determines phenotype (including physiological phenotype), regulation of this process can influence heritable transcription and can thus result in epigenetic physiological effects (e.g. Ho and Burggren, 2009). Two examples of this regulation include DNA methylation and histone modification.…”