Meeting Abstract
The mangrove rivulus, Kryptolebias marmoratus, is one of the two known self-fertilizing hermaphroditic vertebrates, resulting in populations composed of distinct homozygous and isogenic strains. Despite no or low genetic diversity within a strain, this fish displays remarkable levels of phenotypic plasticity. The present study investigated developmental plasticity induced by a chronic exposure to 17-&alpha-ethynylestradiol (EE2) in rivulus, and the role of DNA methylation in driving this plastic response. Hatchlings from a single isogenic lineage were individually exposed during 28 days post hatching (dph) to solvent control, 4 and 120 ng/L of EE2, and then transferred to clean salt water until 180 dph. We aim to link global DNA methylation and methylation at specific GpG sites of selected genes to both cellular (proteome) and organismal phenotypes (hormone levels, behavior, growth, reproductive success) measured during the course of the experiment. Preliminary results show that at 28 dph, both standard length (SL; 12.6 ± 0.4 vs 13.4 ± 0.4 mm) and mass (31.9 ± 3.4 vs 37.8 ± 3.6 mg) were significantly lower in fish exposed to 120 ng/L compared to control. In the 4 ng/L group, only SL was significantly lower than control (13.0 ± 0.5 vs 13.4 ± 0.4 mm). At 56 dph, only SL of individuals exposed to 120 ng/L treatment differed from control (16.5 ± 0.4 vs 17.0 ± 0.5 mm). A first examination of global DNA methylation showed that the proportion of methylated CpG sites might be lower than what is reported in other fish species.
