Mapping of MYF5, C1R, MYHL, TPI1, IAPP, A2MR and RNR onto sheep chromosome 3q.

Five new loci, myogenic factor 5 (MYF5), complement 1 receptor (CIR), myosin-like heavy chain (MYHL), islet amyloid polypeptide (IAPP), and alpha-2-macroglobulin receptor (A2MR), were mapped onto sheep chromosome 3q by Southern hybridization to a panel of chromosomally characterized sheep x hamster cell hybrid lines. The location of the triose phosphate isomerase (TPI1) gene and one of the nucleolar organizer regions (RNR) on sheep 3q was confirmed by Southern analysis. This study provides further evidence for the existence of a large conserved chromosomal segment comprising much of sheep chromosome 3q, cattle chromosome 5, and human chromosome 12. The distal evolutionary breakpoint on human chromosome 12, producing the chromosomal segment U23 in cattle marked by aldehyde dehydrogenase (ALDH2), also produces a separate segment in sheep. Neither ALDH2 nor pancreatic lipase (PLA2), which is also distally located on human chromosome 12, were mapped onto sheep chromosome 3q.