DNA Sequence Characteristics and Phylogenetics of Putative Imprinted Genes on Bovine Chromosome 29

Cattle are important livestock species with huge genetic resource for food security, agriculture and livelihoods. Over 60% of its genes are homologous to all mammalian species which creates a molecular basis for conducting comparative genomic analysis. Genomic imprinting has been implicated in a variety of biological functions and so identification of new or verification of known imprinted genes in livestock species is of high agricultural and biomedical importance. Fourteen (14) putative imprinted genes on bovine chromosome 29 (Bta 29) as well as the human (Hg 11) and mouse (Mm 7) orthologs were computationally characterized with respect to the CpG islands (CGI), transcription factor binding elements and sequence motif. Phylogenetic analysis was conducted across the three species for each of the genes identified to have promoter CGI. Promoter CGI were identified in ASCL2, TSSC4, CDKN1C, KCNQ1, PHLDA2 and NAP1L4. The promoter CGI were enriched with CpG containing transcription factor binding sites. Generally, it was observed that cattle was more closely related to human than mouse and that natural selection was the force driving the evolutionary change between the three species. Protein kinase motifs involved in phosphorylation were identified in the amino-acid sequences of ASCL2, TSSC4, PHLDA2 and NAP1L4. Our results suggest the post-translation regulation of imprinting and that the predicted promoter CGI can be assayed to determine molecular function, gene expression and DNA methylation status of the bovine putative imprinted genes.