Who are the Okinawans? Ancestry, genome diversity, and implications for the genetic study of human longevity from a geographically isolated population.
Isolated populations have advantages for genetic studies of longevity from decreased haplotype diversity and long-range linkage disequilibrium. This permits smaller sample sizes without loss of power, among other utilities. Little is known about the genome of the Okinawans, a potential population isolate, recognized for longevity. Therefore, we assessed genetic diversity, structure, and admixture in Okinawans, and compared this with Caucasians, Chinese, Japanese, and Africans from HapMap II, genotyped on the same Affymetrix GeneChip Human Mapping 500K array. Principal component analysis, haplotype coverage, and linkage disequilibrium decay revealed a distinct Okinawan genome-more homogeneity, less haplotype diversity, and longer range linkage disequilibrium. Population structure and admixture analyses utilizing 52 global reference populations from the Human Genome Diversity Cell Line Panel demonstrated that Okinawans clustered almost exclusively with East Asians. Sibling relative risk (λs) analysis revealed that siblings of Okinawan centenarians have 3.11 times (females) and 3.77 times (males) more likelihood of centenarianism. These findings suggest that Okinawans are genetically distinct and share several characteristics of a population isolate, which are prone to develop extreme phenotypes (eg, longevity) from genetic drift, natural selection, and population bottlenecks. These data support further exploration of genetic influence on longevity in the Okinawans.
Department of Mathematics, Rowan University, Glassboro, New Jersey. bendjilali@rowan.edu.
Nasrine
N
Bendjilali
Departments of Medicine and Epidemiology & Biostatistics, University of California, San Francisco.
Wen-Chi
WC
Hsueh
Pacific Health Research and Education Institute, Honolulu, Hawaii. Department of Research, Kuakini Medical Center, Honolulu, Hawaii.
Qimei
Q
He
D Craig
DC
Willcox
Department of Psychiatry, University of California, San Diego, La Jolla.
Caroline M
CM
Nievergelt
Pacific Health Research and Education Institute, Honolulu, Hawaii. Ohana Genetics, Honolulu, Hawaii.
Timothy A
TA
Donlon
Department of Dermatology, Institute for Human Genetics, and Cardiovascular Research Institute, University of California, San Francisco.
Pui-Yan
PY
Kwok
Okinawa Research Center for Longevity Science, Urasoe, Okinawa, Japan. Faculty of Medicine, University of the Ryukyus, Nishihara, Okinawa, Japan.
Makoto
M
Suzuki
Pacific Health Research and Education Institute, Honolulu, Hawaii. Department of Research, Kuakini Medical Center, Honolulu, Hawaii. Okinawa Research Center for Longevity Science, Urasoe, Okinawa, Japan. Department of Geriatric Medicine, John A Burns School of Medicine, University of Hawaii, Honolulu, Hawaii.
Bradley J
BJ
Willcox
D000369:Aged, 80 and over; D044466:Asian People / Q000235:genetics*; D002874:Chromosome Mapping; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D007564:Japan; D008017:Life Expectancy; D008136:Longevity / Q000235:genetics*; D008297:Male; D012016:Reference Values
Ancestry; Genome diversity; HapMap.; Longevity; Okinawa