The purpose of project was an identification of the key genes and pathways associated with final stage of oocyte maturation in birds. Novel candidate genes and pathways were identified as playing roles in protein ubiquitination and synthesis, sirtuin and estrogen receptor signaling.

The germinal disc region of mature oocyte at F1 developmental stage were obtained from six 38-wk-old turkeys. The gene expression pattern were determined by high-throughput transcriptome sequencing. The obtained sequence reads were mapped to the turkey genome. Six subfamilies of zona pellucida (ZP) genes, ZP1-4, ZPD and ZPAX were identified.Bioinformatics analysis revealed that many of the identified genes were involved in key steps of protein synthesis via eIF2, elF4 and p70S6K signaling pathways and degradation via ubiquitination. Detailed analysis of transcripts classified in estrogen receptor (ESR) signalling indicated presence of ESR1 and ESR2 and a set of estrogen-dependent genes involved in both genomic and non-genomic mechanism of regulation of gene expression by estrogen.Oxidative phosphorylation was found to be a possible source of ATP in the mature bird oocyte and nuclear factor erythroid 2–related factor signaling pathway could be involved in response against oxidative stress. Here, we identified the key physiological process involved in the final stage of oocyte maturation and taking part in inner perivitelline layer preparation for fertilization. The identified genes/proteins can be potentially used to characterize the specific mechanism of bird reproduction.