A queen honeybee and her female workers have identical DNA sequences but obvious differences in behaviour and reproductive ability. This can be explained, in part, by the attachment of methyl groups to the bees' DNA, which changes gene expression. Now researchers have found significant differences in the methylation patterns of more than 550 genes — most of which are involved in essential cellular activities such as metabolism and RNA synthesis.
Ryszard Maleszka at the Australian National University in Canberra and his team analysed genomes from the brain tissue of reproductive queens and sterile workers to reveal the genome-wide distribution of methyl groups. They found that methylation sites clustered in areas of genes where splicing — a form of cutting and pasting — occurs in the RNA that is transcribed from the gene. The authors say that methylation may influence the splicing process to generate different gene products.