Polymorphic DNA markers genetically linked to disease-causing genes: a review.

Abstract

Prior to the development of recombinant DNA techniques, the human gene map consisted largely of a set of genes mapped to specific chromosomal locations via analysis of their products in rodent x human hybrid somatic cells. Available markers left large areas of the genome unmapped and in some instances entire chromosomes remained with out a polymorphic marker. It was primarily for this reason that attempts to establish linkages to disease-causing genes were largely unsuccessful. The discovery of restriction fragment length polymorphisms (RFLPs) at the DNA level now renders imminent the generation of a complete human linkage map. In the immediate term this will facilitate the development of carrier detection, pre-symptomatic or diagnostic tests for inherited disorders and in the longer term the isolation, structural and functional analysis of the genes responsible for the cause of the more common hereditary diseases. An outline is presented of the techniques involved in the use of recombinant DNA in diagnostic genetics of the practical applications and implications of this form of technology.