title: The genetically isolated populations of Finland and sardinia may not be a panacea for linkage disequilibrium mapping of common disease genes.
abstract: The choice of which population to study in the mapping of common disease genes may be critical. Isolated founder populations, such as that found in Finland, have already proved extremely useful for mapping the genes for specific rare monogenic disorders and are being used in attempts to map the genes underlying common, complex diseases. But simulation results suggest that, under the common disease-common variant hypothesis, most isolated populations will prove no more useful for linkage disequilibrium (LD) mapping of common disease genes than large outbred populations. There is very little empirical data to either support or refute this conclusion at present. Therefore, we evaluated LD between 21 common microsatellite polymorphisms on chromosome 18q21 in 2 genetic isolates (Finland and Sardinia) and compared the results with those observed in two mixed populations (United Kingdom and United States of America). Mean levels of LD were similar across all four populations. Our results provide empirical support for the expectation that genetic isolates like Finland and Sardinia will not prove significantly more valuable than general populations for LD mapping of common variants underlying complex disease.
authors.affiliation: Wellcome Trust Centre for Molecular Mechanisms in Disease, Department of Medical Genetics, Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Cambridge, UK.
authors.forename: I A
authors.initials: IA
authors.lastname: Eaves
authors.forename: T R
authors.initials: TR
authors.lastname: Merriman
authors.forename: R A
authors.initials: RA
authors.lastname: Barber
authors.forename: S
authors.initials: S
authors.lastname: Nutland
authors.forename: E
authors.initials: E
authors.lastname: Tuomilehto-Wolf
authors.forename: J
authors.initials: J
authors.lastname: Tuomilehto
authors.forename: F
authors.initials: F
authors.lastname: Cucca
authors.forename: J A
authors.initials: JA
authors.lastname: Todd
mesh_terms: D002874:Chromosome Mapping; D002887:Chromosomes, Human, Pair 18; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics*; D005387:Finland; D005838:Genotype; D006801:Humans; D007558:Italy; D015810:Linkage Disequilibrium; D018895:Microsatellite Repeats; D011110:Polymorphism, Genetic