Data from: Distinct patterns of inheritance shape life-history traits in steelhead trout

Life-history variation is the raw material of adaptation, and
understanding its genetic and environmental underpinning is key to
designing effective conservation strategies. We used large-scale genetic
pedigree reconstruction of anadromous steelhead trout (Oncorhynchus
mykiss) from the Russian River, California, USA to elucidate sex-specific
patterns of life-history traits and their heritability. SNP data from
adults returning from sea over a 14-year period were used to identify
13,474 parent-offspring trios. These pedigrees were used to determine age
structure, size distributions, and family sizes for these fish, as well as
to estimate the heritability of two key life-history traits, spawn date
and age at maturity (first reproduction). Spawn date was highly heritable
(h2 = 0.73) and had a cross-sex genetic correlation near unity. We provide
the first estimate of heritability for age at maturity in ocean-going fish
from this species and found it to be high heritable (h2 from 0.29–0.62,
depending upon sex and calculation), with a much lower genetic correlation
across sexes. We also evaluated genotypes at a migration-associated
inversion polymorphism and found sex-specific correlations with age at
maturity. The significant heritability of these two key reproductive
traits in these imperiled fish, and their patterns of inheritance in the
two sexes, is consistent with predictions of both natural and sexually
antagonistic selection (sexes experience opposing selection pressures).
This emphasizes the importance of anthropogenic factors, including
hatchery practices and ecosystem modifications, in shaping the fitness of
this species, thus providing important guidance for management and
conservation efforts.