Deep divergence and apparent sex-biased dispersal revealed by a Y-linked marker in rainbow trout

Abstract

Y-chromosome and mitochondrial DNA markers can reveal phylogenetic patterns by allowing tracking of male and female lineages, respectively. We used sequence data from a recently discovered Y-linked marker and a mitochondrial marker to examine phylogeographic structure in the widespread and economically important rainbow trout (Oncorhynchus mykiss). Two distinct geographic groupings that generally correspond to coastal and inland subspecies were evident within the Y marker network while the mtDNA haplotype network showed little geographic structure. Our results suggest that male-specific behavior has prevented widespread admixture of Y haplotypes and that gene flow between the coastal and inland subspecies has largely occurred through females. This new Y marker may also aid conservation efforts by genetically identifying inland populations that have not hybridized with widely stocked coastal-derived hatchery fish.

A conserved haplotype controls parallel adaptation in geographically distant salmonid populations

“…This genome‐wide pattern of genetic diversity differs from a previously examined Y‐linked locus at which coastal subspecies (such as Sw and WR) are very similar to each other but deeply divergent from inland subspecies (such as Cl) (Brunelli et al. 2010).…”

“…Interestingly, these two lines originate from very distant geographical locations and belong to distinct subspecies of O. mykiss . The Cl line originated near the extreme east of the O. mykiss native range (North Fork Clearwater River, North Central Idaho) and belongs to the inland subspecies, whereas Sw originated near the extreme north (Swanson River, Southcentral Alaska) and belongs to the coastal subspecies (Allendorf & Utter 1979; Behnke & Tomelleri 2002; Brunelli et al. 2010).…”

Genetic Differentiation and Origin of Naturalized Rainbow Trout Populations From Southern Chile, Revealed by the mtDNA Control Region Marker

“…These groups represent five groups of mitochondrial DNA (mtDNA) genotypes according to phylogenetic analysis, a result that mostly shows agreement with the morphological data (Bagley and Gall, 1998). This strong genetic structuring of rainbow trout has also been supported in other regions across their native distribution range (Nielsen et al, 1997;Narum et al, 2004;Brunelli et al, 2010;Taylor et al, 2010;Abadía-Cardoso et al, 2015).…”

“…For example, in genuine selfsustaining populations of this continent this haplotype shows a frequency of only 7.5%. The MYS03C-RTDL34-EU haplotype has been reported at low frequency in Europe, but it is more frequent in native populations, particularly those from Oregon (Brunelli et al, 2010). Pairwise genetic distances among naturalized populations of rainbow trout from southern Chile and native populations were also estimated by using p-distance that was calculated using MEGA v. 5.05 software.…”

The Adaptive Sex in Stressful Environments

“…In lizards and fish, there is no clear general pattern of sex-biased dispersal, although juvenile males have been reported to disperse more in some lizards [88] and migrating fish (e.g. Oncorhynchus mykiss [89]). The picture is clearer for mammals in which males generally (but not always) disperse more than females, while the reverse is typically observed in birds [90,91].…”