Combining extremely concordant sibpairs with extremely discordant sibpairs provides a cost
effective way to linkage analysis of quantitative trait loci
Chi Gu, A. Todorov, D.C. Rao
Genet Epidemiology , 13, 513-533 (1996)
Abstract
Extremely discordant (ED) sibpairs have been shown to be very
powerful for linkage analysis of human quantitative traits [Risch and
Zhang (1995) Science 268:1584-1589]. In many cases, the extremely
concordant (EC) sibpairs collected in the process of screening for ED
sibpairs carry valuable information for linkage. Therefore, it seems
justifiable to investigate the advantages of genotyping and to include
them with the ED sibpairs for linkage analysis. Herein we explore the
distributions of EC as well as ED sibpairs under various genetic
models and provide a basis for combining both types of sibpairs. A
simple statistic testing means of genes shared identical by descent
(IBD) is applied to combine both types of EC sibpairs (high-high and
low-low) with the ED pairs. We show that when a decent number of
EC pairs is added to the ED sample for analysis, the power is much
enhanced, making it especially desirable when the number of
available ED pairs is small. We show at the same time that
combining EC pairs with ED pairs is more cost effective than
pursuing ED sibpairs alone.
Allele-sharing linkage analysis