Standard G-, Q-, and R-banded ideograms of the domestic sheep (Ovis aries): homology with cattle (Bos taurus). Report of the committee for the standardization of the sheep karyotype

Revised G-, Q- and R-banded karyotypes and ideograms for sheep chromosomes at the 420-band level of resolution are presented. The positions of landmar k bands on the sheep chromosomes are defined by their distance relative to the centromere to facilitate comparison with equivalent cattle chromosomes. Chromosome-specific (reference) molecular markers that have been mapped to sheep chromosomes and their equivalent cattle chromosomes are proposed. Re ference markers will facilitate genome comparisons between sheep and cattle and minimise confusion due to chromosome nomenclature. Numbering of the Ro bertsonian translocation chromosomes remains as previously reported.