Title: Genetic data associated with a description of mating systems and predictors of relative reproductive success in Yellowstone Cutthroat Trout (Oncorhynchus clarkii bouvieri) Authors: John S. Hargrove, Jesse McCane, Curtis J. Roth, Brett High, Matthew R. Campbell Contact: john.hargrove@idfg.idaho.gov Date of data collection: May to October 2016 Geographic Location: Burns Creek, a tributary to the South Fork Snake River, Idaho. USA. Date file created: 07/12/21 Article DOI: 10.1002/ece3.7914 Article Title: Mating systems and predictors of relative reproductive success in a Cutthroat Trout subspecies of conservation concern Journal: Ecology and Evolution Methods: The genetic data set provided was generated via sampling of Yellowstone Cutthroat Trout at a weir on a spawning tributary (Burns Creek) of the South Fork Snake River, Idaho, USA. Each migrating adult was sampled for a genetic sample and the length and date of sampling was recorded for each individual. Juveniles emigrating from the same system later the same year were also sampled for genetics. In the lab, DNA was extracted and each individual was amplified at a panel of 167 single nucleotide polymorphisms (SNPs) using a Genotyping-in-Thousands (GT-seq) protocol. Parentage analysis was performed using the algorithms implemented in SNPPIT, specifically juveniles were assigned to parent-pairs. We created reproductive profiles for each adult including the number of offspring assigned, number of mates. Analysis of genetic mating systems involved summarizing the means and variances of reproductive success (offspring assigned) and mating success (number of mates) for each sex. We compared phenotypic traits of fish that did and did not mate to test for evidence of sexual selection. The data file contains the following headings: Collection - this specifies whether a sample is an adult or juvenile IndividualName - this represents a unique identifier for each fish present in the dataset LengthTotal - this value corresponds to total length in millimeters Sex - the genetic sex of each adult. Note - sex was not determined/included for juveniles Each subsequent column represents a locus name. Note: for each locus there are two alleles, each recorded in its own unique column. As a result, the same locus name will have two columns, one denoted -A1 (allele 1) and the second A2 (allele 2).