Sex matters: Otolith shape and genomic variation in deacon rockfish (Sebastes diaconus)

Abstract

Little is known about intraspecific variation within the deacon rockfish (Sebastes diaconus), a recently described species found in the northeast Pacific Ocean. We investigated population structure among fish sampled from two nearshore reefs (Siletz Reef and Seal Rock) and one offshore site (Stonewall Bank) within a <50‐km2 area off the Oregon coast. Fish from the three sample sites exhibited small but statistically significant differences based on genetic variation at >15,000 neutral loci, whether analyzed independently or classified into nearshore and offshore groups. Male and females were readily distinguished using genetic data and 92 outlier loci were associated with sex, potentially indicating differential selection between males and females. Morphometric results indicated that there was significant secondary sexual dimorphism in otolith shape, but further sampling is required to disentangle potential confounding influence of age. This study is the first step toward understanding intraspecific variation within the deacon rockfish and the potential management implications. Since differentiation among the three sample sites was small, we consider the results to be suggestive of a single stock. However, future studies should evaluate how the stock is affected by differences in sex, age, and gene flow between the nearshore and offshore environments.

Evaluating Human Autosomal Loci for Sexually Antagonistic Viability Selection in Two Large Biobanks

“…These results stand in contrast to previous studies, that have reported tens to hundreds of significantly differentiated variants with mean autosomal male-female F ST values ranging from 1% to 45% [14][15][16][17][18][19] . These studies suggest strong, pervasive sexually antagonistic viability selection acting across the genomes of various species, which would be puzzling in light of theoretical observations and simulations indicating that strong allelic divergence between the sexes requires high sex-specific mortality rates to overcome the homogenizing effect of meiotic segregation occurring every generation 13 .…”

“…Recent research has looked for these effects by identifying alleles with high male-female F ST 10,12,13 , a normalized measure of allele frequency difference. Such studies across a range of taxa have suggested that potentially hundreds of autosomal loci are subject to ongoing sexually antagonistic selection with many differentiated loci having male-female divergence values of at least 10% [14][15][16][17][18] , and some reaching even as high as 45% 19 . The production and maintenance of such large male-female differences would require strong, ongoing selection, because alleles are homogenized every generation by meiotic segregation 12,13 .…”

“…To overcome previous limitations, we use two large-scale biobanks, the UK Biobank and the Vanderbilt Biobank (BioVU). Compared to previous studies examining sexual antagonism, these datasets significantly improve our statistical power to detect allele frequency differences among the sexes by providing the largest available sample sizes to date -several orders greater than previous studies in humans 12,16 and non-model taxa [14][15][16][17][18][19] . We analyze >500,000 human genomes for signals of male-female divergence driven by sexually antagonistic selection.…”

The search for sexually antagonistic genes: Practical insights from studies of local adaptation and statistical genomics

“…2019; Vaux et al. 2019) or from breeding individuals (Dutoit et al. 2018), yet it remains unclear how much information about SA selection is contained within these estimates.…”

First documentation of the otoliths of the species of Gouania (Teleostei: Gobiesocidae) in the Mediterranean Sea

“…As the sample available for each species was small (and the body sizes of specimens varied within and among groups), no conclusions could be drawn with regard to within‐species variability of the otoliths such as sexual dimorphism (Teimori et al ., 2020; Vaux et al ., 2019), ontogenetic variation (Vignon, 2012; Więcaszek et al ., 2020) or asymmetry between right and left otoliths (Lord et al ., 2012; Lychakov et al ., 2008; Panfili et al ., 2005). Nonetheless, some preliminary remarks can be made based on the comparison between otolith groups.…”