Non-genetic inheritance and changing environments

Until recently, biological information was thought to be transmitted across generations by DNA sequencing alone. Furthermore, adaptation to the environment was thought to only occur with Darwin's mechanism of rare mutations of the DNA that are selected for the reproductive advantage that they provide. However, scientists are now paying increased attention to non-DNA factors that are inherited and can actually help offspring adapt to their environment. An article published last week in Non-Genetic Inheritance -- an open access journal by Versita, brings attention to this new mode of inheritance. The authors refer to a process called Transgenerational plasticity (TGP). Plasticity is a term used to describe how an organism changes its phenotype (e.g. morphology, physiology or behaviour) to adapt to its environment. For example, some animals become more hairy when bred in cold conditions. Transgenerational plasticity refers to offspring developing the adaptations, when the parents experience the environment.

An international group of scientists led by Dr. Santiago Salinas from the University of California Santa Cruz, highlight the potential importance of non-genetic inheritance in an area of increasing public concern. Although non-genetic inheritance is still a poorly understood factor in population responses to rapid environmental change, the scientists succeed in presenting accumulated evidence to indicate that animals and plants are using a new method to adapt to changes in the environment.

Dr. Salinas and his colleagues put forward a convincing argument that not only could non-genetic fast-acting mechanisms of adaptation be widespread in nature (complimenting the slower DNA-mutation based methods of adaptation) but that they could also be of increasing importance as rapid climate change continues. In an extensive catalogue of examples they suggest that non-genetic inheritance mechanisms are being used in a wide variety of life forms. Salinas surveyed 80 empirical studies from 63 species to argue that the new adaptive method is sufficiently established both theoretically and empirically to merit inclusion as a coping tactic against rapid environmental changes. Moreover, modulation of the system could be used in agriculture to ensure that crop species are fully adapted to their environments.

Commenting on the surveys, Eva Jablonka from The Cohn Institute for the History and Philosophy of Science and Ideas, at Tel Aviv University, says: "This excellent review raises pertinent questions about the adaptability of organisms and opens up important research questions. It is a vital contribution to our understanding on how organisms adapt to changing conditions, and I agree with the authors that trans-generational plasticity has to be considered if we are to predict the response of organisms to such conditions, an issue that seems to be of particular significance today."