Open AccessAge‐specific survivorship and fecundity shape genetic diversity in marine fishes
Author(s) -
Barry Pierre,
Broquet Thomas,
Gagnaire PierreAlexandre
Publication year - 2022
Publication title -
evolution letters
Language(s) - English
Resource type - Journals
ISSN - 2056-3744
DOI - 10.1002/evl3.265
Subject(s) - fecundity , biology , genetic diversity , survivorship curve , vital rates , range (aeronautics) , ecology , population , genetic variation , evolutionary biology , effective population size , zoology , demography , genetics , gene , population growth , cancer , materials science , sociology , composite material
Genetic diversity varies among species due to a range of eco‐evolutionary processes that are not fully understood. The neutral theory predicts that the amount of variation in the genome sequence between different individuals of the same species should increase with its effective population size ( N e $N_{e}$ ). In real populations, multiple factors that modulate the variance in reproductive success among individuals causeN e $N_{e}$ to differ from the total number of individuals ( N $N$ ). Among these, age‐specific mortality and fecundity rates are known to have a direct impact on theN e / N ${N_{e}}/{N}$ ratio. However, the extent to which vital rates account for differences in genetic diversity among species remains unknown. Here, we addressed this question by comparing genome‐wide genetic diversity across 16 marine fish species with similar geographic distributions but contrasted lifespan and age‐specific survivorship and fecundity curves. We sequenced the whole genome of 300 individuals to high coverage and assessed their genome‐wide heterozygosity with a reference‐free approach. Genetic diversity varied from 0.2% to 1.4% among species, and showed a negative correlation with adult lifespan, with a large negative effect ( s l o p e = − 0.089 $slope=-0.089$ per additional year of lifespan) that was further increased when brooding species providing intense parental care were removed from the dataset ( s l o p e = − 0.129 $slope=-0.129$ per additional year of lifespan). Using published vital rates for each species, we showed that theN e / N ${N_{e}}/{N}$ ratio resulting simply from life tables parameters can predict the observed differences in genetic diversity among species. Using simulations, we further found that the extent of reduction inN e / N ${N_{e}}/{N}$ with increasing adult lifespan is particularly strong under Type III survivorship curves (high juvenile and low adult mortality) and increasing fecundity with age, a typical characteristic of marine fishes. Our study highlights the importance of vital rates as key determinants of species genetic diversity levels in nature.