Diseases you may contract throughout your life might be influenced by the diet of your mother while she was pregnant or what you were feed as a baby. It has been long known that genes and the environment influence an organism’s phenotype (appearance). Therefore, causes of disease would be assumed to be genetically or environmentally based. However, a recent study has shown that adult diseases are potentially linked to metastable epialleles, which are types of epigenetic factors. Epialleles are mechanisms of inheritance other than DNA, that have been shown to modify certain characteristics of an individual, passing this on information to offspring. Epialleles are highly influenced by environmental factors, especially those that occur in early embryonic development. Such changes in structure of non-DNA regions at early development, called metastable epialleles, can cause a ‘cascade effect’, where the epialleles spread throughout the body as a result of mitosis. These modifications ultimately alter the expected phenotype, affecting an individual throughout its life. If metastable epialleles lead to a detrimental phenotype, results could be devastating. For example, diets low in folic acid, vitamin B12, choline and betaine affect an epiallele in mice which induces obesity and tumorigenesis. Epialleles that occur in the human epigenome may also have detrimental outcomes. This illustrates the importance of research into how the environment, such as embryonic and post-natal nutrition, affects metastable epialleles, which in turn alters phenotypic characteristics, possibly leading to disease.
References
Dolinoy, D.C., Das, R., Weidman, J.R. and Jirtle, R.L. (2007) Metastable Epialleles, Imprinting, and the Fetal Origins of Adult Diseases, Pediatric Research, 61:30R-37R.
Rakayan, V.K. and Beck, S. (2006) Epigenetic variation and inheritance in mammals, Current Opinion in Genetics and Development, 16:573-577.
Jessica Walsh
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