Genomic Signals of Local Adaptation Associated With Environmental Variables in Eleginops maclovinus From Northern Chilean Patagonia

TL;DR

This study identifies genomic signals of local adaptation in a marine fish species from northern Chilean Patagonia, showing how environmental factors influence genetic changes.

Contribution

The study integrates genomic and environmental data to reveal polygenic selection driving local adaptation in an understudied Patagonian species.

Findings

392 adaptive loci were identified using population genetic differentiation methods.

2164 loci were associated with environmental variables like temperature, salinity, and oxygen.

Polygenic scores showed significant correlations with environmental gradients, indicating polygenic selection.

Abstract

Understanding the evolutionary mechanisms that shape the adaptive divergence across spatially heterogeneous environments is a challenging task for evolutionary ecologists. The Chilean marine Patagonia is a complex ecosystem with diverse geomorphology and physical–chemical oceanographic conditions. There is limited research evaluating the interactions between selective forces and environmental conditions in this area. This study focuses on identifying the genomic signals of local adaptation of the endemic marine fish,
Eleginops maclovinus
, from Chilean North Patagonia. To achieve this goal, we used an environmental marine database (temperature, salinity, oxygen, phosphate, nitrate and silicate) collected from 1995 to 2018 and 11,961 SNPs obtained from 246 individuals from 10 sampling locations across this area. We identified putative adaptive loci using 10 bioinformatic software tools, where five were based on population genetic differentiation (PGD) and five based on genotype‐environment association (GEA). We identified 392 adaptive loci using PGD and 2164 associated with at least one of the six environmental variables analyzed using GEA. A total of 131 loci were shared between the PGD and GEA approaches, of which 37 were associated with genes involved in growth, metabolism, and homeostasis. Then, we evaluated the variation of adaptive loci with environmental variables using polygenic scores and found significant correlations with temperature, salinity, and oxygen, indicating polygenic selection along environmental gradients. This study highlights how polygenic selection drives local adaptation in
Eleginops maclovinus
and underscores the value of integrating genomic and environmental data for conservation in the Patagonian ecosystem.

Studying evolutionary processes in the unique and understudied Patagonian fjord ecosystem is a challenging task for evolutionary ecologists. Genomic signals of local adaptation are present in a species from northern Chilean Patagonia. Polygenic selection drives local adaptation in
Eleginops maclovinus
.

Figures