The characterization of human male-specific 5.7 kb DNA(pKY-1) and its application to fetal sex-determination probe.

A male-specific 5.7 kb DNA(pKY-1) was cloned by screening human genomic libraries. Subsequent to structural characterization, a possibility of its application for prenatal diagnosis probe was tested. The results obtained were as follows: 1) the pKY-1 was specifically hybridized with human Y-chromosome specific repetitive 3.5 kb, but not with female DNA and 2.1 kb, known to be another human Y-specific repetitive-DNA. 2) HaeIII, EcoRI and their double digestion did not produce the Y-specific 3.5 kb fragments from pKY-1. 3) Although the digestion of pKY-1 with BamHI liberated 0.55 kb, ClaI clove remained 5.10 kb into 2.40 and 2.7 kb fragments, while their hybridizabilities with the 3.5 kb DNA were identically conserved. These data suggest that 5.7 kb fragment (pKY-1) should be proposed as a member of Y-chromosome-specific repetitive DNA family in human genome. Thus, this cloned DNA will be not only a useful probe for human fetal sex-determination but also an effective tool for analysis of Y-chromosome with its structure and repetitive DNA.