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.
Nearby loci are present in many of the same clones, proximity inferred.
Distance determined by insert size of YAC library - average is 1 Mb here. Example of linkage determination by STS, genetic and radiation hybrid mapping. Expressed sequences - 921 from complete cDNAs. Kb provides 8.4-fold coverage of the human genome. Hierarchical pooling system.