Biology subjects

Flores, A.-M.

Publications and source records attributed to Flores, A.-M..

3 recordsLinked to original sources

bioRxiv2024

The genome assembly of the westslope cutthroat trout, Oncorhynchus lewisi, reveals interspecific chromosomal rearrangements with the rainbow trout

Cutthroat trout (Oncorhynchus clarkii) are popular among anglers throughout their native range along the West Coast and interior of North America. As they colonized the interior of North America, cutthroat trout diverged into several genetically distinct groups. Many of these groups are now threatened by habitat destruction, hybridization with rainbow trout (O. mykiss), and competition from introduced species. These groups were previously classified as subspecies, but recent research suggests they may represent distinct species. In this study, we produced a chromosomal-level genome assembly and a genetic map for one of the species in the cutthroat trout species complex, the westslope cutthroat trout (O. lewisi--formerly O. clarki lewisi). We also constructed haplotype-resolved assemblies from a westslope cutthroat-rainbow trout F1 hybrid. We used the new genome assemblies to identify major interspecific chromosomal rearrangements between the two sister species, including fusions, fissions, and inversions. These genome assemblies and chromosome data provide valuable insights regarding genetic variation within cutthroat trout and in hybrids between rainbow and cutthroat trout. Article SummaryWestslope cutthroat trout inhabit bodies of water in several states and provinces near the Rocky Mountains and are well-known among anglers. In this study, we produced the first publicly available genome assemblies and a high-density genetic map for this species. These are research tools that allow detailed genetic analyses, including identifying differences among the genomes of related species. These comparisons allow researchers to understand the evolution of these species better and may provide insight into why successful interbreeding is possible among cutthroat and rainbow trout.

genomics↗

bioRxiv2024

Revealing the evolutionary history and contemporary population structure of Pacific salmon in the Fraser River through genome resequencing

The Fraser River once supported massive salmon returns, but now years with half of the recorded historical maximum are considered good. There is substantial interest from surrounding communities, governments, and other groups to increase salmon returns for both human use and for functional ecosystems. To help generate resources for this endeavour, we resequenced hundreds of genomes at moderate coverage ([~]16x) of Chinook (Oncorhynchus tshawytscha), coho (O. kisutch), and sockeye salmon (O. nerka) from the Fraser River. The resequenced genomes are an important resource that can give us new insights. In this study, we found evidence that Chinook salmon have 1.5-2x more polymorphic loci than coho or sockeye salmon. Using principal component analysis (PCA) and admixture analysis, we also identified genetic groups similar to those previously identified with only a few microsatellite markers. As the higher density data supports these previous genetic groups, it suggests that the identity of these groups is not overly sensitive to the number of genetic markers or when the groups were sampled. With the increased resolution from resequenced genomes, we were able to further identify factors influencing these genetic groups, including isolation-by-distance, migration barriers, recolonization from different glacial refugia, and environmental factors like precipitation. We were also able to identify 20 potentially adaptive loci among the genetic groups by analyzing runs of homozygosity. All of the resequenced genomes have been submitted to a public database where they can be used as a reference for the contemporary genomics of Fraser River salmon. Article SummaryConcerns over Fraser River salmon declines led us to generate resources to better understand the genetics of these salmon. Our findings were similar to previous studies that examined a very small fraction of the genetic markers examined here. We expanded upon previous studies by identifying possible influences on the genetics of Fraser River salmon. These included environmental factors, historical differences, and a lack of connectivity in the river caused by the Fraser Canyon.

evolutionary biology↗

bioRxiv2021

The pink salmon genome: uncovering the genomic consequences of a strict two-year life-cycle

Pink salmon (Oncorhynchus gorbuscha) adults are the smallest of the five Pacific salmon native to the western Pacific Ocean. Pink salmon are also the most abundant of these species and account for a large proportion of the commercial value of the salmon fishery worldwide. A strict two-year life-history of most pink salmon generates temporally isolated populations that spawn either in even-years or odd-years. To uncover the influence of this genetic isolation, reference genome assemblies were generated for each year-class and whole genome re-sequencing data was collected from salmon of both year-classes. The salmon were sampled from six Canadian rivers and one Japanese river. At multiple centromeres we identified peaks of Fst between year-classes that were millions of base-pairs long. The largest Fst peak was also associated with a million base-pair chromosomal polymorphism found in the odd-year genome near a centromere. These Fst peaks may be the result of centromere drive or a combination or reduced recombination and genetic drift, and they could influence speciation. Other regions of the genome influenced by odd-year and even-year temporal isolation and tentatively under selection were mostly associated with genes related to immune function, organ development/maintenance, and behaviour.

genomics↗