Comparative genome analysis in farm animals using cross-species chromosome painting

Comparative chromosome painting is a recent addition to the growing number of tools available to perform comparative genome analysis. The technique uses whole, arm or partial chromosome-specific paints (WCPs, ASPs and PCPs) across evolutionarily distantly related species, resulting in the delineation of conserved chromosomal segments. The technique edges over other genome comparison methods by physically defining the boundaries of homologies on the chromosomes. During the past three years, several domestic and farm animal species have been analysed using this approach. These include pig, cattle, sheep, buffalo, horse, cat and mink. In the majority of cases, human paints have been used as probes. However, there are instances where, for example, pig or cat WCPs have been used on human chromosomes (reverse/reciprocal painting), or pig WCPs used on cattle chromosomes. The findings not only provide vital clues regarding comparative genome organization in these species, but are of significance in the rapid expansion of their gene maps by accurate transfer of genetic information from the highly developed human gene map.