Physical mapping of ADCY2, FSHB and HBB to bovine chromosome 15 by FISH of bovine bacterial artificial chromosome clones

Follicle stimulating hormone beta -subunit gene (FSHB) has been physically mapped to HSA 11 pter arrow right p11.2 and BTA 15q24 arrow right qter. The beta hemoglobin gene (HBB) was mapped to HSA 11p15.5 and BTA 15q13 arrow right q23. Although adenylate cyclase 2 (ADCY2) has yet to be cytogenetically mapped in bovine, it has been assigned in human to HSA 5p15.3 arrow right p15.1. Available cytogenetic data allowed the direct delineation of a conserved segment including the ADCY2 gene, between HSA 5 and BTA 15. Since FSHB and HBB have been mapped isotopically to broad chromosome band intervals and ADCY2 has yet to be cytogenetically assigned, the objective here was to use bovine bacterial artificial chromosome (BAC) clones in FISH to cytogenetically anchor the BTA 15 genome map with high precision. The FISH assignments of HBB and FSHB are consistent with those made isotopically, although the use of FISH has allowed us to map more precisely these two loci to BTA 15. Because HBB and FSHB were shown to map proximately in single color-FISH, two color-FISH was used to confirm that FSHB is distal to HBB. The present assignment of ADCY2 to BTA 15q14 arrow right q21 is the first physical assignment of this locus in bovine. The ADCY2, HBB and FSHB genes were also placed in the framework map of BTA 15 (Amarante et al., unpublished) using the bovine Whole Genome Radiation Hybrid (WG-RH) panel. The order and position of these three genes in the WG-RH map of BTA 15 corroborate results presented for FISH mapping in this study and reinforce the existence of homologous regions between HSA 5, HSA 11 and BTA 15.