Plant, Animal & Microbe Genomes X Conference

January 12-16, 2002
Town & Country Convention Center
San Diego, CA

Poster: Genome Sequencing & ESTs
            

DRAFT GENOMIC SEQUENCE OF THE BOVINE MHC IIB REGION

¹ College of Veterinary Medicine, Texas A&M University, College Station, TX 77843 USA

² Human Genome Sequencing Center, Baylor College of Medicine, Houston TX 77030 USA

The major histocompatibility complex (MHC) of cattle was disrupted by an ancient chromosomal rearrangement that placed a portion of the class II region (designated IIB) near the centromere on BTA 23. Similar rearrangements have been observed cytogenetically in other ruminants and gene mapping data suggest that the rearrangement was a large inversion. We have recently completed the first draft sequence of the bovine IIB region using random sequencing of M13 subclones derived from arrayed large insert BAC clones. Our sequence analysis of more than 500 kb is consistent with the inversion hypothesis and reveals that the centromeric breakpoint of IIB is about 40 kb distal from the gamma glutamyl cysteine synthase catalytic subunit (GCLC) locus. The first genetic locus identified from the centromeric end of IIB encodes an intact class II DRB4-like gene with an open reading frame. Thirteen other genes were identified in the same order as found in the human MHC extending to RXRB. THe bovine IIB region is rich in SINEs and contains 50 di- and trinucleotide microsatellites, most of which are (CA:GT) repeats.