P0971 Prediction of CpG Islands in 5 Putative Imprinted Genes on Bovine Chromosome 29

Oyeyemi O. Ajayi , Federal University of Agriculture, Abeokuta, Nigeria
Marcos De Donato , Cornell University, Ithaca, NY
Sunday O. Peters , Cornell University, Ithaca, NY
Ikhide Imumorin , Cornell University, Ithaca, NY
The expression pattern of imprinted genes is thought to be governed by the presence of CpG islands as targets of epigenetic processes such as DNA methylation, which leads to differential regulation of gene expression. In a previous analysis, we localized 901 putative imprinted genes to the bovine genome, and found a cluster on chromosome 29 with 14 imprinted genes. In this study, we performed in-silico prediction of CpG islands in the promoters, exons and introns of 5 of these genes compared to their human and mouse orthologs. CpG islands were detected in 3 genes (IGF2, TH and ASCL2), however, there was a net loss in the number of CpG islands detected in human and most especially in mouse compared to cattle; particularly for INS and TSPAN32 genes. The highest number of CpG islands was observed in cattle when compared to orthologs in human and mouse. It therefore appears that there are putative, species-specific CpG islands that could presumably contribute to differential expression of genes in diverse species. CpG islands detected in ASCL2 gene overlapped with promoter region suggesting functional involvement in gene expression regulation. Our results showed that the distribution and presence of CpG islands differ across species and putative imprinted genes, and on average, most of the CpG islands observed in cattle have higher CG content (>70%) compared to their human and mouse orthologs, a feature with relevance in experimental studies of these putative imprinted genes in the bovine genome.