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Migration‐related phenotypic divergence is associated with epigenetic modifications in rainbow trout
Author(s) -
Baerwald Melinda R.,
Meek Mariah H.,
Stephens Molly R.,
Nagarajan Raman P.,
Goodbla Alisha M.,
Tomalty Katharine M. H.,
Thorgaard Gary H.,
May Bernie,
Nichols Krista M.
Publication year - 2016
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/mec.13231
Subject(s) - biology , epigenetics , differentially methylated regions , rainbow trout , phenotypic plasticity , dna methylation , smoltification , genetics , phenotype , evolutionary biology , regulation of gene expression , gene , gene expression , salmonidae , fish <actinopterygii> , fishery
Abstract Migration is essential for the reproduction and survival of many animals, yet little is understood about its underlying molecular mechanisms. We used the salmonid Oncorhynchus mykiss to gain mechanistic insight into smoltification, which is a morphological, physiological and behavioural transition undertaken by juveniles in preparation for seaward migration. O. mykiss is experimentally tractable and displays intra‐ and interpopulation variation in migration propensity. Migratory individuals can produce nonmigratory progeny and vice versa, indicating a high degree of phenotypic plasticity. One potential way that phenotypic plasticity might be linked to variation in migration‐related life history tactics is through epigenetic regulation of gene expression. To explore this, we quantitatively measured genome‐scale DNA methylation in fin tissue using reduced representation bisulphite sequencing of F 2 siblings produced from a cross between steelhead (migratory) and rainbow trout (nonmigratory) lines. We identified 57 differentially methylated regions ( DMR s) between smolt and resident O. mykiss juveniles. DMR s were high in magnitude, with up to 62% differential methylation between life history types, and over half of the gene‐associated DMR s were in transcriptional regulatory regions. Many of the DMR s encode proteins with activity relevant to migration‐related transitions (e.g. circadian rhythm pathway, nervous system development, protein kinase activity). This study provides the first evidence of a relationship between epigenetic variation and life history divergence associated with migration‐related traits in any species.