A LOCUS ON CHROMOSOME 11P WITH MULTIPLE RESTRICTION SITE POLYMORPHISMS

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  • 1 January 1984
    • journal article
    • research article
    • Vol. 36  (6) , 1159-1171
Abstract
A new polymorphic locus was discovered and characterized on chromosome 11p, D11S12, defined by an arbitrary genomic DNA segment cloned in the plasmid pADJ762. Four different polymorphic restriction sites with minor allele frequencies greater than 5% are revealed by Southern hybridization of this probe and its derivatives to digests of human DNA. These include 2 MspI sites, a TaqI site and a BclI site. The frequencies of the common haplotypes at this locus were determined in a Utah [USA] population. Significant linkage disequilibrium was demonstrated to exist between some pairs of polymorphic sites. A molecular map of this region was determined, and the polymorphic sites were localized. Comparison of physical separation with degree of linkage disequilibrium reveals an interesting case where an MspI site and a TaqI site that are separated by 6.8 kilobases (kb) show a greater degree of disequilibrium with each other than they do with 2 polymorphic sites located between them. One of the 2 interior sites is a BclI site that is .apprx. 0.2 kb away from the TaqI site but shows the same degree of disequilibrium with the TaqI site as with the MspI site 6.7 kb away. Although there is significant linkage disequilibrium at this locus, there are 4 major haplotypes with frequencies of 5% or greater, and the polymorphic information content (PIC) of this locus is 0.64.