Annotation of the GNAS imprinting region on BTA13 as per build 4.0 of the B. taurus genome sequence. The physical location of each SNP used in this study is indicated in relation to contig BTA13. The SNPs analysed in this study are listed as per their dbSNP accession number http://www.ncbi.nlm.nih.gov/projects/SNP. Two of the reported alternatively spliced GNAS transcripts (ENSBTAT00000002746 [GNAS] and ENSBTAT00000023246 [GNAS2_BOVIN]) are shown here. A third novel GNAS alternatively spliced transcript reported in the ENSEMBL database (ENSBTAT00000023234) is not shown. The direction of transcription is denoted by the hashed lines containing arrowheads. The location of the putative bovine NESP55 first exon is shown and was determined via alignment of the bovine NESP55 mRNA sequence with build 4.0 of the B. taurus genome. In humans and mice transcripts from this exon are spliced to exons 2-13 of the GNAS gene.