Regional localization of 3 Y-derived sequences on the human X and Y chromosomes

The structure of the Y chromosome and the relationship between the human sex chromosomes have been studied using Y-derived sequences cloned in cosmids. Two probes recognize different unique sequences which map to the heterochromatic part of the long arm of the Y chromosome. A third sequence is shared by the long arm of the X chromosome and the euchromatic part of the Y chromosome. Thus homology between the sex chromosomes occurs outside the pairing region.