Correspondence of human chromosomes 9, 12, 15, 16, 19 and 20 with donkey chromosomes refines homology between horse and donkey karyotypes

Whole chromosome paints for human (HSA) chromosomes 9, 12, 15 and 20 and ar m-specific paints for HSA16p, 19p and 19q were applied on donkey metaphase spreads. All probes, except HSA19p, gave distinct hybridization signals on donkey chromosomes/chromosomal segments. The results show direct segmental homology between human and donkey genomes, and enable refinement of corresp ondence between donkey and horse karyotypes. Of specific interest is the id entification of hitherto unknown correspondence between four equine acrocen tric chromosomes (ECA22, 23, 25 and 28) and the donkey chromosomes. Overall , the findings mark the beginning of an ordered study of comparative organi zation of genomes/karyotypes of the equids, that can shed light on karyotyp e evolution and ancestral chromosomal condition in the Perissodactyls.