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Innovative mark-recapture experiment shows patterns of selection on transcript abundance in the wild
  • Matthew Josephson,
  • James Bull
Matthew Josephson
University of Calgary
Author Profile
James Bull
University of Calgary
Author Profile


A fundamental aspect of evolutionary biology is natural selection on trait variation. Classically, selection has been estimated primarily on external morphological traits such as beak size and coloration, or on easily-assayable physiological traits such as heat-tolerance. As technologies and methods improved, evolutionary biologists began examining selection on molecular traits such as protein sequences and cellular processes. In a From the Cover manuscript in this issue of Molecular Ecology, Ahmad et al. (2021) continue this trend by estimating parasite driven selection on the molecular trait of transcript abundance in a wild population of brown trout (Salmo trutta) by uniquely combining a mark-recapture experimental design with non-invasive RNA sampling. Using transcript abundance to estimate selection allows for many different traits (each unique gene’s transcript counts) to be tested in a single experiment, providing the opportunity to examine trends in selection. Ahmad et al.(2021) find directional selection strength on transcript counts is generally low and normally distributed. Surprisingly, transcripts under non-linear selection showed a disruptive selection bias contradicting previous comparative studies and theoretical work. This highlights the importance of within-generation selection studies, where mechanisms may differ from longer time frames. Their manuscript also highlights the benefits of an improved 3’ RNA sequencing technique to measure gene expression.

Peer review status:ACCEPTED

29 Mar 2021Submitted to Molecular Ecology
30 Mar 2021Assigned to Editor
30 Mar 2021Submission Checks Completed
06 Apr 2021Reviewer(s) Assigned
13 Apr 2021Review(s) Completed, Editorial Evaluation Pending
16 Apr 2021Editorial Decision: Accept