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Genetic Diversity and Linkage Disequilibrium in the Polynesian Population of Niue Island

2006; Wayne State University Press; Volume: 78; Issue: 2 Linguagem: Inglês

10.1353/hub.2006.0031

1534-6617

William G.H. Abbott, Ingrid Winship, Edward Gane, Sitaleki A. Finau, Stephen Munn, Colin Tukuitonga,

Forensic Anthropology and Bioarchaeology Studies

Isolated populations that recently have been derived from small homogeneous groups of founders should have low genetic diversity and high levels of linkage disequilibrium and should be ideal for mapping ancestral polymorphisms that influence complex genetic disease susceptibility. Populations that fulfill these criteria have been difficult to identify. We have been looking for Polynesian populations with these characteristics, because Polynesians have high rates of complex genetic diseases. In Niue Islanders all ancestral female (mitochondrial HSV1 sequence) and 90.4% of ancestral male (Y-chromosome haplogroup) lineages are of Southeast Asian origin. The frequency of European Y-chromosome haplogroups is 7.2%. The diversities of mitochondrial HSV1 sequences (h = 0.18 ± 0.05) and Y-chromosome haplogroups (h = 0.18 ± 0.05) are lower than values published for any other population. Ten autosomal microsatellites spaced over 5.8 cM show low allele numbers in Niue Islanders relative to Europeans (55 vs. 88 total alleles, respectively) and a modest reduction in heterozygous loci (0.71 ± 0.02 vs. 0.78 ± 0.02, p = 0.04). The higher linkage disequilibrium (d2 ) between these loci in Niue Islanders relative to Europeans (p = 0.001) is negatively correlated (r = -0.47, p = 0.01) with genetic distance. In summary, Niue Islanders are genetically isolated and have a homogeneous Southeast Asian ancestry. They have reduced autosomal genetic diversity and high levels of linkage disequilibrium that are consistent with the influence of genetic drift mechanisms, such as a founder effect or bottlenecks. High-powered linkage disequilibrium studies designed to map ancestral polymorphisms that influence complex genetic disease susceptibility may be feasible in this population.