Technical Abstract: Turkey sperm lose viability within 8 to 18 hours when stored as liquid semen using current methods and extenders. In contrast, turkey hens maintain viable, fertile sperm in their sperm storage tubules (SST) for 70 or more days following a single insemination. Our long-term objectives are to identify and characterize differentially expressed genes that may underlie this prolonged sperm storage and then use this information to develop improved methods for storing liquid turkey semen. We employed serial analysis of gene expression (SAGE) to compare gene expression patterns in turkey SST recovered from hens after artificial insemination (AI) with extended semen (sperm AI) or extender alone (control AI). We constructed two separate SAGE libraries with SST mRNA obtained from sperm and control AI hens. We used these libraries to generate 95,325 10-base pair SAGE tags. The sperm and control AI libraries contained 47,663 and 47,662 tags representing 18,030 and 19,101 putative unique transcripts, respectively. Tags appearing in both libraries represented 27,430 unique genes. Approximately 1% of these putative unique genes were differentially expressed (P<0.05) between treatments. Tentative annotations were ascribed to the SAGE tag nucleotide sequences by comparing them against publicly available SAGE tag and cDNA sequence databases. Based on its SAGE tag nucleotide sequence, we cloned the turkey avidin gene and confirmed its up-regulation in the sperm AI SST. The bioinformatics and experimental procedures employed to clone turkey avidin and confirm its differential expression represent a useful paradigm for analyzing SAGE tag data from relatively uncharacterized model systems.