Genetic markers detectable by PCR Polymorphisms, usually dinucleotide repeats. Special subset of STSs. T.J. Hudson, et 50 al. Genome project goal is 30,000 STS landmarks with spacing of 100 Kb. Strategy Radiation hybrid mapping - panel of cell lines screened by PCR to identify hybrids retaining particular loci.
Nearby loci show similar retention patterns - linked.
Distance a function of size of retained insert - 10 Mb here. Linkage distance limited by recombination frequency - about 30 Mb. Map can be established with several thousand markers, yielding global information. STS content mapping. YAC libraries screened by PCR for individual loci.