What is epigenetics?

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While genetics studies genes, epigenetics focuses on an additional “layer” of information that determines how these genes are used by a cell … or not used. For example, the same bee larva can become a queen or a worker depending on how it is fed. This is caste polyethism … which can be reversible: a worker can begin to lay eggs if her ovaries are not inhibited by royal pheromones.

After emergence, the worker is first a cleaner, then a nurse, a builder … and finally a forager. This is age polyethism … which can also be reversible: an old winter bee can become a nurse again at the end of January when egg laying resumes.

Methylation is a chemical modification of DNA through the attachment or substitution of a methyl group on certain nucleic bases. Put simply, certain parts of DNA can be temporarily hidden or masked (by methylation) and thus prevented from producing specific proteins/enzymes, thereby modifying the insect itself or its behavior. It is the expression of the same overall genetic code, but environmental factors select one expression rather than another, all of which are available in the “genetic database.” In other words, epigenetics governs how the genotype is used to produce a phenotype.

The genotype, or genetic heritage, refers to the set of hereditary characteristics, whether observable or not. By contrast, the phenotype refers to observable traits or appearance, such as eye color in humans.

To learn more:

► Introduction to bee genetics
► DNA adaptation according to role
► Epigenetics
► The bee genome
► Genetics or epigenetics
► Differentiation of bees into queens and workers: a question of epigenetics