Differential DNA methylation in response to host environment changes in Drosophila gouveai.

Organisms with a single genotype can express different phenotypes in response to rapid environmental changes, an event known as phenotypic plasticity, although the molecular basis is poorly understood. Epigenetic modifications mediate genotype-to-phenotype transitions and are related to phenotypic plasticity. Drosophila gouveai, a cactophilic species found in South America, exhibits morphological changes and differential methylation in its genome during the development; however the phenotypic plasticity is not yet elucidated. In this study, we investigated changes in genomic DNA methylation profiles and molecular targets when D. gouveai develops in Cereus hildmaniannus tissues or P. machrisii cactus. We assessed DNA methylation patterns using the MSAP technique, followed by direct sequencing. Our results indicate that internal methylation (target-CmCGG/CCmGG) comprises 33 loci in the genome in ovarian tissues in flies raised on C. hildmaniannus and 31 loci in flies raised on P. machrisii. In the trials of male flies, we found 42 methylated loci in flies developed on C. hildmaniannus and 21 loci in flies raised on P. machrisii. Epigenetic heterogeneity was observed between D. gouveai ovarian and testicular tissues. Additionally, the Galileo transposon element (TE) is targeted for methylation when flies develop on C. hildmaniannus. Methylation of transposable elements is known to play a role in genome stability. In conclusion, our data suggest that differential methylation occurs in the D. gouveai genome when using different cactus hosts.