Transcriptomic changes in the testes and brain associated with sperm competition risk in male zebra finches

Abstract

We investigated how phenotypic plasticity induced by experimentally manipulated sperm competition risk is reflected in transcriptomic profiles of testes and two brain areas (posterior pallium and optic tectum) in breeding male zebra finches (Taeniopygia guttata). Based on an exceptionally large sample of 59 individual transcriptomes, we compared two experimental groups: males held in single pairs versus two pairs per breeding cage. We found tissue-specific differential gene expression in all three tissues at the level of gene co-expression network modules. The treatment affected multiple cellular functions in the testes, which can be associated with germ cell production and modification. Moreover, neural and glial brain cell changes indicate phenotypic adjustment of male zebra finch behaviour to the social environment. Finally, individual co-expression modules correlated with individual behavioural phenotypes and hormonal profiles. Our pre-registered study shows the importance of transcriptomic plasticity for phenotypic adjustment to male-male competition in zebra finches. Peter Korsten, Uwe Mayer and Tim Schmoll share the last authorship.