Sequence-tagged sites (STSs) from YAC insert-ends and X-specific flow-sorted chromosomes

Sequence-tagged sites (STSs; Olson et al. 1989), specified by primer pairs and their corresponding PCR products, have become a fundamental component of the Human Genome initiative. Biological separation of chromosomes is possible with rodent-human somatic cell hybrids con- taining all or subregions of a single human chromosome. STSs can then be derived, for example, from human-spe- cific Alu-Alu fragments (Cole et al. 1991), or from human- specific plasmids, lambda clones (Green et al. 1991), cos- mids, or YACs (Kere et al. 1992). An alternative is pro- vided by physical separation of a chromosome of interest by flow-sorting. We have analyzed both X-specific YAC end-sequences and fragments of sorted chromosomes as sources of STSs. Chromosomes were sorted from a human lymphoblas- tic cell line (GM1416, obtained from NIGMS Human Ge- netic Mutant Cell Repository) with karyotype 48,XXXX. Chromosomes were then extracted and isolated by the method of Young et al. (1981).