Epigenetics is an exciting and fast developing area of biology. It deals with the study of changes in gene expression and function contributing to the phenotype that, nevertheless, do not involve alterations of the genotype. These changes can be heritable through cell mitoses and even individual generations. They include three major mechanisms that can activate or suppress gene expression: DNA methylation, modification of chromatin structure through alterations in histone proteins, and regulatory processes mediated by small RNAs. Epigenetic changes are actively studied in developmental biology and for their implications in human health, notably in oncology. However, less attention has been paid in other fields, including evolutionary biology and ecology. Since epigenetic processes have been found to be responsible for the integration of both biotic and abiotic factors, epigenetics can help to understand how organisms respond to environmental change. In addition, epigenetic variation may explain phenotypic changes in ecologically important traits observed in natural populations that cannot be explained by genetic variation, and thus how phenotypic plasticity is brought about. Finally, epigenetic modifications can be considered in the light of selection programs to increase animal production. The link between conditions during early development, where many heritable epigenetic marks are established, and gene function later in life is particularly interesting. Thus, proper management of these early conditions may contribute to better growth and health of farmed animals. Because of their external fertilization, fish are excellent research subjects where to study epigenetic changes. Here, these various aspects of epigenetics will be discussed. Among others, an example will be provided on how modifications of a major environmental cue such as temperature is integrated through an epigenetic mechanism, ultimately determining phenotypic sex and growth in a production fish

I Congrés Internacional de Biologia de Catalunya (CIBICAT): Global Questions on Advanced Biology. An international conference on interdisciplinary frontiers in biology. As part of the first Centenary of the Societat Catalana de Biologia. 9-12 July 2012, Barcelona

Supported by grants CSD2007-0002 (Consolider “Aquagenomics”) and AGL2010-15939 (“Epigen-Aqua”)

Peer Reviewed