Establishment of a sequence-based typing system for BoLA-DQA1 exon 2

In cattle, bovine leukocyte antigens (BoLAs) have been extensively used as markers for bovine diseases and immunological traits. Here, we developed a rapid, high-resolution sequence-based typing (SBT) system for BoLA-DQA1. We amplified 355 bp of BoLA-DQA1 by fully nested polymerase chain reaction (PCR) using the newly constructed primers and then performed direct sequencing of each product. Using this method, we investigated the locus in 51 animals whose BoLA haplotypes had been characterized at the Fifth International BoLA Workshop. We identified 15 distinct DQA1 alleles, and there is no conflict between the typing result of PCR-SBT and restriction fragment length polymorphism analysis. Together with the previously developed method for typing BoLA-DRB3, the PCR-SBT for BoLA-DQA1 clearly provides a useful tool for detailed class IIa haplotype analysis.