Gene Body Methylation Evolves During the Sustained Loss of Parental Care in the Burying Beetle

Epigenetic modifications, such as 5-methylcytosine (5mC), can sometimes be transmitted between generations, provoking speculation that epigenetic changes could play a role in adaptation and evolution. Here, we use experimental evolution to investigate how 5mC levels evolve in populations of biparental insect (Nicrophorus vespilloides) derived from a wild source population and maintained independently under different regimes of parental care in the lab. We show that 5mC levels in the transcribed regions of genes (gene bodies) diverge between populations that have been exposed to different levels of care for 30 generations. These changes in 5mC do not reflect changes in the levels of gene expression. However, the accumulation of 5mC within genes between populations is associated with reduced variability in gene expression within populations. Our results suggest that evolved change in 5mC could contribute to phenotypic evolution by influencing variability in gene expression in invertebrates. It's largely unknown whether heritable, but non-genetic, changes can affect evolution. This study shows that changes in epigenetic modifications that evolve in burying beetles are associated with altered variability in gene expression, potentially influencing adaptation.