Chromatin Profiling Reveals Distinct Male and Female Trajectories for Developmental Learning Potential.

Adult patterns of behavior can often be explained by developmental experiences. In some cases, developmental experience can have permanent influence on brain and behavior only during specific ages; these phases are called critical or sensitive periods. Epigenetic mechanisms can regulate both maturational and experiential processes in the brain by coordinating transcription of genes involved in organization and plasticity. Epigenetics thus may have particular relevance to critical periods. As such, we employed ChIP-seq to assess accessible regulatory regions, segments of the genome where transcription factors (TFs) bind, using the epigenetic marker H3K27ac. We focused on the auditory forebrain, required for developmental sensory song learning, in juvenile male and female zebra finches (Taeniopygia guttata). Both sexes rely on developmental sensory learning to bias adult behaviors, though males have a defined critical period for this process, whereas it is not clear that females do. Thus, we sought to address two major questions: (1) Are H327ac peaks changing in males as they transition into their critical period, and if so, how?, and (2) How similar are the female H3K27ac peaks at the same ages of development? Our analyses revealed that age and sex affect H3K27ac-based peak profiles and enriched TF binding sites within them, as well as genes annotated to those H3K27ac-defined peaks. These findings provide new insights into how epigenetic regulation may influence auditory forebrain organization and function in the context of changing learning potential across a sensitive developmental period and create a foundation for additional studies.