Meeting Abstract
A mother’s hormonal response to her environment can cause permanent changes in her developing offspring, potentially determining whether those offspring succeed in a given environment. Females breeding in more competitive environments tend to transfer more testosterone to their offspring prenatally, which permanently makes offspring more aggressive. This maternal effect may help offspring adapt to competitive environments, yet it is still unclear how maternally derived testosterone is able to permanently affect offspring behaviors. Without knowing the mechanisms, it is difficult to characterize the heritability of this maternal effect and how it fits into larger evolutionary frameworks. In this study, we have injected captive zebra finch (Taeniopygia guttata) eggs with a control vehicle or testosterone and measured aggressive and competitive behaviors in the resulting offspring. We found that offspring from testosterone-injected eggs grew faster, begged longer, and were more aggressive. In a subset of male and female offspring from both treatments, we tested for genome-wide differences in mRNA expression and site-specific methylation patterns in two socially-relevant brain regions, the nucleus taeniae of the amygdala and hypothalamus. This research is among the first to test if molecular mechanisms, such as stable changes in gene regulation (i.e., DNA methylation), underlie the programming of offspring aggression by maternal hormones in songbirds.
