Proportion of informative families for genetic counseling with linked marker genes

Abstract

The utility of linked marker genes for genetic counseling depends on the gene frequencies and dominance relationship at the marker locus as well as on the recombination value between the marker and disease gene loci. A quantity called the proportion of informative families was introduced to measure the effect of gene frequencies and dominance relationship on the utility of marker genes. This proportion is higher for X-linked genes than for autosomal genes, other things being equal. It is also higher for codominant markers than for marker genes with dominance. It is shown that when gene frequencies are appropriate linked marker genes are quite useful for genetic counseling. Examples are given by using real data on G6PD, colorblindness, the ABO blood groups, etc. © 1979 The Japan Society of Human Genetics.