Sexual dimorphism and host genetics shape the gut microbiome of northern
elephant seal pups (Mirounga angustirostris)
Abstract
Due to a population bottleneck, northern elephant seals (Mirounga
angustirostris ) have very low genetic diversity, making them ideal
model organisms for assessing the impact of genetic and non-genetic
factors on the gut microbiome. In our study, we were especially
interested in the role of sex given the northern elephant seal’s extreme
sexual dimorphism. We investigated 54 northern elephant seal pups that
were rescued from along the California coastline and brought to The
Marine Mammal Center, a rehabilitation facility. Using a metabarcoding
approach, we characterized microbial communities shortly after admission
to the facility and found that both sex and geographic origin explained
microbial variation. We detected significant differences in microbial
class and order composition between sexes. We further analyzed paired
samples from 24 seals at two time points, shortly after admission to the
rehabilitation facility and a month post-acclimation in the facility.
Between these two time points, microbial diversity increased, likely due
to changes in diet. While there was an overall convergence of microbiome
composition in a shared environment over time, remaining differences in
microbial composition were explained by sex and host genetics.