Bovine ovarian follilce selection

Lack of, or abnormal, ovarian follicular development prevents establishment of pregnancy in human and is associated with reduced reproductive efficiency in farm animals. Development of new treatments is limited by our poor understanding of ovarian follicular development. The objective of this study is to identify changes in gene expression during the selection stage of bovine follicular growth. Follicles of different sizes were collected and intrafollicular concentrations of steroids were measured to identify healthy follicles. Gene expression profiles were obtained using cDNA slides containing ~18,000 bovine EST probes. Using a false discovery rate of 0.05, we identified 976 probes differentially expressed across different follicles with at least 1.4 fold changes. Genes involved in immune system, cell organization and biogenesis, and cell proliferation were significantly over represented in the list, indicating the potential involvement of these biological processes in follicular selection. Keywords: gene expression, follicle stage comparison RNA samples from the 16 largest follicles of 16 heifers with the follicle size of 8mm to 12 mm were used in the hybridization. A design with two samples hybridized on each array and each samples repeated 3 times (swap dyes) on different arrays was used.