Ovarian transcriptomic analysis reveals the alternative splicing events associated with fecundity in different sheep breeds.

Alternative splicing (AS) is one of the most common mechanisms that accounts for the greater macromolecular and cellular complexity of higher eukaryotic organisms. This study focused on the splicing events in the ovaries of different sheep breeds, namely the Han and Dorset breeds. Of the groups studied, cassette splicing events accounted for the maximum number of the AS events with significant differences, whereas the splicing events that were mutually exclusive with introns accounted for the smallest proportion of splicing events. Greater than 1000 AS events with significant differences were identified between the Han BB and Dorset sheep. The number of AS events with significant differences between Han ++ and Dorset sheep, however, was fewer than that of the comparison of Han BB and Dorset sheep. Seven randomly selected genes with AS events were detected in this study and were validated by reverse transcription-polymerase chain reaction (RT-PCR). Furthermore, there are many genes which were common to the two genotype groups (Han BB and Dorset sheep, as well as the Han ++ and Dorset sheep). In addition, genes detected in the present study were involved in different pathways, including the pathways related with fertility or fecundity. The present study could provide the detailed understanding on the mechanisms of alternative splicing events associated with fecundity in different sheep breeds.