Two different epigenetic information channels in wild three-spined sticklebacks are involved in salinity adaptation
Melanie J. Heckwolf, Britta Meyer, Robert Häsler, Marc P. Höppner, Christophe Eizaguirre, Thorsten B. H. Reusch
Abstract
) along a salinity cline. Wild populations differing in salinity tolerance revealed differential methylation (pop-DMS) at genes enriched for osmoregulatory processes. A two-generation experiment demonstrated that 62% of these pop-DMS were noninducible by salinity manipulation, suggesting that they are the result of either direct selection or associated genomic divergence at cis- or trans-regulatory sites. Two-thirds of the remaining inducible pop-DMS increased in similarity to patterns detected in wild populations from corresponding salinities. The level of similarity accentuated over consecutive generations, indicating a mechanism of transgenerational plasticity. While we can attribute natural DNA methylation patterns to the two information channels, their interplay with genomic variation in salinity adaptation is still unresolved.