Duplication and polymorphism in the MHC: Alu generated diversity and polymorphism within the PERB11 gene family

The PERB11 gene family has at least five members within the telomeric region of the MHC. The PERB11.1 and PERB11.2 genes are approximately 40 kb and 160 kb centromeric of HLA-B, respectively. Using continuous genomic sequence encompassing PERB11.1 and PERB11.2, we have found a large (approximately 25 kb) segmental duplication extending beyond the genes themselves and other potential coding sequences. The major difference between the segments are large indels which are predominantly Alu sequences. The Alu sequences within the duplicated segments have created diversity via the internal and 3' poly A-rich region. A sequence comparison of an Alu sequence between two different human ancestral haplotypes shows a high level of polymorphism, particularly in the poly A-rich regions. This study characterises the Alu sequences within the peri-PERB11.1 and peri-PERB11.2 duplicated segments in relation to diversity and polymorphism and as evolutionary markers.