Data from: DNA methylation and potential for epigenetic regulation in Pygospio elegans

Transitions in developmental mode are common evolutionarily, but how and
why they occur is not understood. Developmental mode describes larval
phenotypes, including morphology, ecology and behavior of larvae, which
typically are generalized across different species. The polychaete worm
Pygospio elegans is one of few species polymorphic in developmental mode,
with multiple larval phenotypes, providing a possibility to examine the
potential mechanisms allowing transitions in developmental mode. We
investigated the presence of DNA methylation in P. elegans, and, since
maternal provisioning is a key factor determining eventual larval
phenotype, we compared patterns of DNA methylation in females during
oogenesis in this species. We demonstrate that intragenic CpG site DNA
methylation and many relevant genes necessary for DNA methylation occur in
P. elegans. Methylation-sensitive AFLP analysis showed that gravid females
with offspring differing in larval developmental mode have significantly
different methylation profiles and that the females with benthic larvae
and non-reproductive females from the same location also differ in their
epigenetic profiles. Analysis of CpG sites in transcriptome data supported
our findings of DNA methylation in this species and showed that CpG
observed/expected ratios differ among females gravid with embryos destined
to different developmental modes. The differences in CpG site DNA
methylation patterns seen among the samples suggest a potential for
epigenetic regulation of gene expression (through DNA methylation) in this
species.