Whole‐genome resequencing confirms reproductive isolation between sympatric demes of brown trout ( Salmo trutta ) detected with allozymes

作者：Atal Saha, Anastasia Andersson, Sara Kurland, Naomi Keehnen, Verena E. Kutschera, Ola Hössjer, Diana Ekman, Sten Karlsson, Marty Kardos, Gunnar Ståhl, Fred W. Allendorf, Nils Ryman, Linda Laikre · 发表于：Molecular Ecology · 年份：2021 · DOI：10.1111/mec.16252 · 被引用次数：20 · 研究领域：Genetic diversity and population structure、Fish Ecology and Management Studies、Environmental DNA in Biodiversity Studies

Abstract The sympatric existence of genetically distinguishable populations of the same species remains a puzzle in ecology. Coexisting salmonid fish populations are known from over 100 freshwater lakes. Most studies of sympatric populations have used limited numbers of genetic markers making it unclear if genetic divergence involves certain parts of the genome. We returned to the first reported case of salmonid sympatry, initially detected through contrasting homozygosity at a single allozyme locus (coding for lactate dehydrogenase A) in brown trout in the small Lakes Bunnersjöarna, Sweden. First, we verified the existence of the two coexisting demes using a 96‐SNP fluidigm array. We then applied whole‐genome resequencing of pooled DNA to explore genome‐wide diversity within and between these demes; nucleotide diversity was higher in deme I than in deme II. Strong genetic divergence is observed with genome‐wide F ST ≈ 0.2. Compared with data from populations of similar small lakes, this divergence is of similar magnitude as that between reproductively isolated populations. Individual whole‐genome resequencing of two individuals per deme suggests higher inbreeding in deme II versus deme I, indicating different degree of isolation. We located two gene‐copies for LDH‐A and found divergence between demes in a regulatory section of one of these genes. However, we did not find a perfect fit between the sequence data and previous allozyme results, and this will require further rese...