In a study by researchers from Johns Hopkins University and Arizona State University, the first evidence of reversible epigenetic changes associated with behavior in any organism is observed in honey bees.
Bees are born into specific castes based on the kind of treatment they received as larvae. While the distinctions between say, a queen bee and a worker bee are fixed for life, the subcastes of worker bee are more flexible. For example, a nurse bee (a type of worker bee who stays in the hive to take care of the queen) usually becomes a forager bee (a worker bee who gathers pollen) later in life. The differences between these two types of worker bee can be seen be seen in their respective patterns of methylation.
In the study, "Reversible switching between epigenetic states in honeybee behavioral subcastes", researchers removed all of the nurse bees from a hive while the forager bees were out collecting honey. When the forager bees returned, 50% of them became nurse bees. However, this change was not only limited to behavior - the methylation patterns of DNA in their brain cells had reversed to those seen in nurse bees.
As Andrew Feinberg of Johns Hopkins explains, "What is exciting is that the genes that change back are the same genes that changed in the other direction initially — and the same ones that would regulate epigenetic behaviour"
However, the implications go far beyond just bees. In the following excerpt from a recent Nature article Andrew Feinberg and fellow researcher Gro Andam explain the relevance for human biology:
A greater understanding of how epigenetics affects behaviour may lead to insights into human biology, Feinberg says, noting that epigenetic effects on human behaviour might express themselves in addiction, learning and memory. If the link between behaviour and methylation patterns “is true in a bee, it is likely to also be true in us”, he says.
This does not mean that artificially changing the methylation pattern of DNA would result in a desired behaviour, but “it would be great if that was feasible”, says Amdam. “Reversing possible ‘bad’ epigenetic marks in human physical and psychological diseases is already a big research interest in biomedicine. Perhaps bees can be used to figure out how it could be done.”