Mapping the BDA20 gene to BTAX

The lipocalin family is a large group of proteins that exhibits great structural and functional variation both within and among species, including a significant number of animal-derived aeroallergens, such as the bovine BDA20 (major cow dander allergen). This protein is classified as an occupational allergen causing asthma and other work-related allergic disorders among dairy farmers. Using a somatic cell panel the BDA20 gene was assigned to the bovine X chromosome (BTAX) with a significant concordant value of 97% to the previously mapped reference marker MAF45. A radiation hybrid (RH) mapping approach confirmed the assignment of BDA20 to BTAX. Two-point LOD scores showed that BDA20 is linked to XBM451 with a LOD score of 22.1 for a theta value of 0.03.

Physical mapping of CSF2RA, ANT3 and STS on the pseudoautosomal region of bovine chromosome X

The pseudoautosomal region (PAR) of bovine chromosome X (BTA X) has a particularly low representation of genes and markers, making comparative gene mapping in this region difficult. We describe the localization of three genes, colony-stimulating factor 2 receptor alpha (CSF2RA), ADP/ATP translocase 3 (ANT3) and steroid sulphatase (STS) on PAR of BTA X using a 5000 rad whole-genome radiation hybrid panel. The relationship of these genes to a number of previously mapped simple sequence repeat (microsatellite) markers is determined by physical and radiation hybrid mapping methods. The resulting radiation hybrid map resolves a discrepancy between the two major bovine linkage maps in the PAR of BTA X.