A genomic survey of linkage disequilibrium

Journal Article · Thu Sep 01 04:00:00 EDT 1994 · American Journal of Human Genetics

OSTI ID:133360

Peterson, A; Freimer, N ^[1]; Slakin, M ^[2]

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1. Univ. of California, San Francisco, CA (United States)
2. Univ. of California, Berkeley, CA (United States)

Linkage disequilibrium (LD), the association of alleles between two or more loci, is a powerful tool for genetic mapping. LD is governed by recombination, mutation, selection, and population admixture; little is known about their relative importance or the distribution of LD across the genome. We used microsatellite markers to conduct a survey of the genomic distribution of LD on chromosome 4, which was chosen because an available radiation hybrid map enabled assessment of LD distribution based on genetic as well as physical distance. To minimize the effect of admixture, we studied a population from Finland, which has a long history of relative isolation. We compared the informativeness of haplotyped and genotyped samples. 33 markers were typed; 29 significant pairwise associations were observed (p<0.05). Although LD was detected between several loci apparently separated by > 2 cM on linkage maps, it was rarely detected between loci separated by more than 40 centiRays on the radiation hybrid map (about 2 megabases). In several instances, LD was not detected between adjacent markers apparently seperated by < 1 cM. In most of these cases, one locus had low heterozygosity or multiple recombination events were directly observed. Contrary to expectation, there was no evident correlation between the ratio of genetic/physical distance and detection of LD; this is likely partially due to the imprecision of linkage maps over small distances. Detection of LD was roughly equivalent in the haplotyped and genotyped samples, probably reflecting the inadequacy of current methods for detection of LD across multiple loci in a single analysis. Conclusion: LD is widely distributed across large genome regions. Marker heterozygosity and physical distance are correlated with detection of LD, and directly observed recombination events may be more useful than linkage maps in evaluating genetic distance in relation to detection of LD.

• OSTI ID: 133360
• Report Number(s): CONF-941009--
• Journal Information: American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
99 GENERAL AND MISCELLANEOUS
ALGORITHMS
BIOLOGICAL MARKERS
DNA HYBRIDIZATION
GENE RECOMBINATION
GENES
GENETIC MAPPING
HUMAN CHROMOSOMES
RADIATION INDUCED MUTANTS
RESOLUTION