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Consistent long-range linkage disequilibrium generated by admixture in a Bantu-Semitic hybrid population
1Department of Biology, University College London, London, United Kingdom.
American Journal of Human Genetics
|August 30, 2000
Summary
Human population history dramatically shapes genome-wide linkage disequilibrium (LD) patterns. Understanding these diverse LD patterns is crucial for genetic association studies across different populations.
Area of Science:
- Human Genetics
- Population Genetics
- Genomics
Background:
- Optimal marker density for genome scans and candidate gene studies rely on linkage disequilibrium (LD) patterns.
- Genomic LD patterns vary significantly across human populations due to diverse demographic histories.
Purpose of the Study:
- To demonstrate conclusively that human demographic histories create substantial differences in genomewide LD patterns.
- To investigate the impact of admixture on LD patterns within specific populations.
Main Methods:
- Utilized a panel of 66 markers across the X chromosome.
- Analyzed LD patterns in the Lemba (a hybrid population), Bantu, and Ashkenazi populations.
- Examined the relationship between allele frequency differences and LD in admixed populations.
Main Results:
- In the Lemba population, markers up to approximately 21 centimorgans (cM) apart showed significant LD.
- In populations with less admixture, excess LD was only observed for markers less than 2 cM apart.
- A significant correlation between allele frequency differentials and observed LD in the Lemba confirmed admixture as a major contributor to excess LD.
Conclusions:
- Demographic history profoundly influences LD patterns, making a priori prediction impossible.
- Empirical evaluation of LD patterns is essential for all populations of interest in genetic studies.
- Admixture is a significant driver of observed LD patterns in hybrid populations.