Heritability and cross-sex genetic correlations of early-life circulating testosterone levels in a wild mammal

Abstract

Testosterone is an important hormone that has been shown to have sex-specific links to fitness in numerous species. Although testosterone concentrations vary substantially between individuals in a population, little is known about its heritable genetic basis or between-sex genetic correlations that determine its evolutionary potential. We found circulating neonatal testosterone levels to be both heritable (0.160 + 0.064 s.e.) and correlated between the sexes (0.942 + 0.648 s.e.) in wild red deer calves (Cervus elaphus). This may have important evolutionary implications if, as in adults, the sexes have divergent optima for circulating testosterone levels.

Annual changes in the concentrations of free triiodothyronine, progesterone and testosterone in prepubertal red deer (<i>Cervus elaphus elaphus</i>) males and females

“…These differences concern, for instance, the deposition and mobilization of fat tissue and its adoption as a metabolic substrate, which may act as an evolutionary response to various energy expenditures related to further stages of life (Power and Schulkin, 2008). To support our hypothesis, it is worth noticing that there are reports indicating that even in neonates, the presence of sex steroids resulting from genetic gender affects features that develop entirely during adulthood (Pavitt et al, 2014).…”

“…According to the published reports concerning red deer, the duration of the prepubertal period was evaluated on the basis of low concentrations of progesterone in the females and testosterone in the males (Asher et al, 2011;Pavitt et al, 2014). Based the observed concentrations of these hormones, we may presume that the examined animals were prepubertal from the beginning of the experiment in November to September the following year.…”

Hormonally Mediated Increases in Sex-Biased Gene Expression Accompany the Breakdown of Between-Sex Genetic Correlations in a Sexually Dimorphic Lizard

“…Future work could strengthen this inference by testing for ontogenetic changes in r mf for the expression of the growth-regulatory genes that we have identified as likely candidates due to their sex-biased expression and responsiveness to testosterone, such as those in the GH/IGF pathway. Characterizing h 2 and r mf for circulating testosterone levels (Pavitt et al 2014;Iserbyt et al 2015), as well as genetic correlations between testosterone and gene expression, could further clar-ify these mechanisms. Last, manipulating testosterone in the context of a quantitative-genetic breeding design while confirming associated changes in gene expression would directly test whether this hormone structures r mf for growth and body size by virtue of its effects on gene expression (Cox et al 2016b).…”

Sex‐specific plasticity and genotype × sex interactions for age and size of maturity in the sheepshead swordtail, Xiphophorus birchmanni

“…Tests of the hypothesis that shared genetic architecture constrains sex‐specific adaptation have focussed largely on estimating the cross‐sex genetic correlation (subsequently denoted r MF ) for homologous traits expressed in males and females (Walling et al ., ; e.g. Pavitt et al ., ). Strong cross‐sex correlations, whether positive or negative, mean that sex‐specific homologous traits are not free to evolve independently of one another.…”