Chromosomal mapping of beta-globin and albino loci in the domestic cat. A conserved mammalian chromosome group.

Siamese cats are homozygous for the recessive cs allele of the color (albino) locus. The c locus is shown here by backcross analysis to be linked to the beta-hemoglobin (HBB) locus in the cat at a distance of approximately eight centiMorgans. The HBB locus and, by inference, the c locus were assigned to feline chromosome D1, by analysis of genomic DNAs from a panel of rodent X cat somatic cell hybrids with a molecular clone of the human beta-globin locus. Evolutionary conservation of the synthetic homology of feline chromosome D1 and human chromosome 11 is extensive. Comparison of high resolution G-trypsin-banded preparations of the two chromosomes permitted cytological alignment of the long arm of the conserved chromosomes providing that a minimum of one paracentric inversion is hypothesized. The placement of the albino locus on conserved syntenic groups of several markers (HBB, HRAS, LDHA) in both cat and mouse strongly indicates the conservative placement of the as yet unmapped human albino locus in the homologous syntenic group on human chromosome 11p.