Chromosomal assignments of three random RFLP loci defined by base-pair changes in MspI sites.

Three cloned single copy sequences isolated from a random partial plasmid library of human EcoRI-HindIII restriction fragments detect MspI site polymorphisms in human DNA. Since at least two of them have allele frequencies that make them suitable for family linkage studies, we have determined their chromosomal localizations. DNA samples extracted from a panel of 31 Chinese hamster x human somatic cell hybrids, that were derived from six different human donors, were analyzed for the presence of human EcoRI or HindIII fragments hybridizing with the three probes. The results were correlated with the human chromosome contents of the hybrids. Concordancy was observed for clone pMS 1-14 (preliminary locus designation DOSLC3) and human chromosome 15, for clone pMS 1-27 (DOSLC2) and chromosome 20, and for clone pMS 1-37 (DOSLC1) and chromosome 3. Two independent hybrids had retained only the long arm of chromosome 3 and did not hybridize with this probe. Therefore, we assign this locus (now termed D3S3) to the short arm of chromosome 3.