Clarification of chromosome nomenclature in the sheep (Ovis aries). Report of the committee for the standardization of the sheep karyotype.

In gene mapping, it is obviously essential that gene assignment errors are minimized. Recently, confusion has arisen in sheep gene mapping, as a result of contradictions in chromosome nomenclature. The purpose of this brief communication, prepared by the International Sheep Karyotype Standardization Committee, is to minimize any further confusion that may arise, while new sheep standard Q, G and R karyotypes and ideograms are being prepared. This paper reviews the history of previous sheep karyotype standards, explains the errors that have been detected and presents a correlation table so that, whichever nomenclature is used, the exact chromosome can be identified.