Strategies For Characterizing Highly Polymorphic Markers in Human
Gene Mapping
J.Ott
American Journal of Human Genetics , 51(2), 283--290 (1992 Aug)
Abstract
Before new markers are thoroughly characterized, they are usually
screened for high polymorphism on the basis of a small panel of
individuals. Four commonly used screening strategies are compared in
terms of their power to correctly classify a marker as having
heterozygosity of 70% or higher. A small number of typed individuals
(10, say) are shown to provide good discrimination power between
low- and high-heterozygosity markers when the markers have a small
number of alleles. Characterizing markers in more detail requires
larger sample sizes (e.g., at least 80-100 individuals) if there is
to be a high probability of detecting most or all alleles. For
linkage analyses involving highly polymorphic markers, the practice
of arbitrarily assuming equal gene frequencies can cause serious
trouble. In the presence of untyped individuals, when gene
frequencies are unequal but are assumed to be equal in the analysis,
recombination-fraction estimates tend to be badly biased, leading to
strong false-positive evidence for linkage.
Comment in: Am J Hum Genet, 52(1):212--213 (1993 Jan)
Comment in: Am J Hum Genet, 52(1):213--214 (1993 Jan)
