Characterization of gene expression involved in pig reproduction. Sus scrofa

Purpose: Recent development in high-throughput sequencing techniques (RNA-seq) has enabled large scale analysis of genetic variations and gene expression in different tissues and species, but gene expression patterns and genetic variations in livestock have not yet been well characterized. In this study we have used high-throughput transcriptomic sequencing of the Finnish Yorkshire to identify gene expression patterns within the breed in the testis and oviduct. Methods: The Solid 4 reads were mapped against the pig genome build 10.2 using the colorspace alignment tool provided by Applied Biosystems and distributed with the instrument (LifeScope v2.1). Reads associated with ribosomal RNA, transfer RNA, repeats and other uninformative reads were filtered out during the process as well as reads with more than 10 potential alignments. After alignment to the reference genome, low mapping quality reads were discarded (mapQV(<10)) and unique reads were associated with known genes based on UCSC annotations, and the number of reads aligned within each gene was counted. FPKM values were calculated for normalization of the data to remove variation between samples caused by non-biological reasons using the Cufflinks software v2.0.2. Results: The analysis of gene expression differences between the testis and oviduct highlighted 1,234 genes up-regulated in the testis and 1,501 in the oviduct. Conclusions: The RNA-seq technology used in this study provides novel information about transcript expression and differential gene expression in the testis and oviduct. The produced data will assist in the identification of candidate genes based on association mapping results within the pig population and provides insights into the expression of genes in the two reproductive organs studied. Overall design: Testis and oviduct mRNA profiles of adult WT and immotile short tail sperm (ISTS) affected Finnish Large White pigs were generated by deep sequencing using Solid 4 platform.