Migration‐related phenotypic divergence is associated with epigenetic modifications in rainbow trout

• DOI: 10.1111/mec.13231
• Publication Date: 2015-05-11T07:53:08Z
• Authors: Melinda R. Baerwald; Mariah H. Meek; Molly R. Stephens; Raman P. Nagarajan; Alisha M. Goodbla; Katharine M. H. T...; Gary H. Thorgaard; Bernie May; Krista M. Nichols
• Keywords: Differentially methylated regions; Smoltification

Migration is essential for the reproduction and survival of many animals, yet little understood about its underlying molecular mechanisms. We used salmonid Oncorhynchus mykiss to gain mechanistic insight into smoltification, which a morphological, physiological behavioural transition undertaken by juveniles in preparation seaward migration. O. experimentally tractable displays intra- interpopulation variation migration propensity. Migratory individuals can produce nonmigratory progeny vice versa, indicating high degree phenotypic plasticity. One potential way that plasticity might be linked migration-related life history tactics through epigenetic regulation gene expression. To explore this, we quantitatively measured genome-scale DNA methylation fin tissue using reduced representation bisulphite sequencing F2 siblings produced from cross between steelhead (migratory) rainbow trout (nonmigratory) lines. identified 57 differentially methylated regions (DMRs) smolt resident juveniles. DMRs were magnitude, with up 62% differential types, over half gene-associated transcriptional regulatory regions. Many encode proteins activity relevant transitions (e.g. circadian rhythm pathway, nervous system development, protein kinase activity). This study provides first evidence relationship divergence associated traits any species.