Effect of riverscape and exotic introgression on the genetic structure and local adaptation of the endangered Mexican golden trout ( )

How environmental and anthropogenic factors influence genetic variation and local adaptation is a central issue in evolutionary biology. The Mexican golden trout (
), one of the southernmost native salmonid species in the world, is susceptible to climate change, habitat perturbations and the introduction of exotic rainbow trout (

) for aquaculture. The present study aimed to explore the effect of both genetic introgression from

and riverscape variables on the genetic variation of

. Genotyping-by-sequencing (GBS) was applied to generate 9 767 single nucleotide polymorphisms (SNPs), genotyping 270

and aquaculture trout. Population genomics analyses were combined with riverscape genetics approaches. A small degree of admixture was identified between aquaculture and native trout, and significant effects of riverscape variables on genetic diversity were detected, as well as evidence of isolation by riverscape resistance within a basin. Gene-environment associations identified genes potentially implicated in adaptation to local hydroclimatic variables. This is an integrative study using a non-common multi-scale approach in landscape genetics for the conservation of an endangered riverine species.