5 REGIONAL LOCALIZATIONS TO THE SHEEP GENOME - FIRST ASSIGNMENTS TO CHROMOSOME-5 AND CHROMOSOME-12

The regional localization of five reference loci to sheep chromosomes is reported. The newly mapped loci are the T-cell receptor, beta (TCRB ), coagulation factor X (F10), laminin gamma 1 (LAMC1), cyclic GMP rod phosphodiesterase, alpha (PDEA) and fibroblast growth factor 2 (FGF2) . The assignments of PDEA and LAMC1 to chromosomes 5q23-q31 and 12q22- q24 respectively provide the first markers physically assigned to thes e chromosomes. They also allow the provisional assignment of sheep syn tenic group U19 to chromosome 5 and U1 to chromosome 12. The mapping o f FGF2 to chromosome 17q23-q25 anchors the unassigned linkage group 'A ' to chromosome 17, and the assignment of TCRB to chromosome 4q32-qter facilitates the orientation of a linkage group on sheep chromosome 4. The mapping of F10 to sheep chromosome 10q23-qter supports the recent assignment of bovine syntenic group U27 to cattle chromosome 12, as s heep chromosome 10 and cattle chromosome 12 are banded homologues.