We studied human population structure using genotypes at 377 autosomal microsatellite loci in 1056 individuals from 52 populations. Within-population differences among individuals account for 93 to 95% of genetic variation; differences among major groups constitute only 3 to 5%. Nevertheless, without using prior information about the origins of individuals, we identified six main genetic clusters, five of which correspond to major geographic regions, and subclusters that often correspond to individual populations. General agreement of genetic and predefined populations suggests that self-reported ancestry can facilitate assessments of epidemiological risks but does not obviate the need to use genetic information in genetic association studies. (+info)
Reduced Y-chromosome, but not mitochondrial DNA, diversity in human populations from West New Guinea.
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To investigate the paternal population history of New Guinea, 183 individuals from 11 regional populations of West New Guinea (WNG) and 131 individuals from Papua New Guinea (PNG) were analyzed at 26 binary markers and seven short-tandem-repeat loci from the nonrecombining part of the human Y chromosome and were compared with 14 populations of eastern and southeastern Asia, Polynesia, and Australia. Y-chromosomal diversity was low in WNG compared with PNG and with most other populations from Asia/Oceania; a single haplogroup (M-M4) accounts for 75% of WNG Y chromosomes, and many WNG populations have just one Y haplogroup. Four Y-chromosomal lineages (haplogroups M-M4, C-M208, C-M38, and K-M230) account for 94% of WNG Y chromosomes and 78% of all Melanesian Y chromosomes and were identified to have most likely arisen in Melanesia. Haplogroup C-M208, which in WNG is restricted to the Dani and Lani, two linguistically closely related populations from the central and western highlands of WNG, was identified as the major Polynesian Y-chromosome lineage. A network analysis of associated Y-chromosomal short-tandem-repeat haplotypes suggests two distinct population expansions involving C-M208--one in New Guinea and one in Polynesia. The observed low levels of Y-chromosome diversity in WNG contrast with high levels of mtDNA diversity reported for the same populations. This most likely reflects extreme patrilocality and/or biased male reproductive success (polygyny). Our data further provide evidence for primarily female-mediated gene flow within the highlands of New Guinea but primarily male-mediated gene flow between highland and lowland/coastal regions. (+info)
Ciguatera poisoning in Vanuatu.
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Ciguatera poisoning is endemic in many tropical and subtropical countries. We conducted a retrospective study of admissions to two hospitals on the islands of Vanuatu in the southwestern Pacific region. We estimated the annual hospital admission rate for fish poisoning to be 65 (95% confidence interval [CI] = 55-75)/100,000 population on the island of Santo and 29 (95% CI = 19-43)/100,000 population on the island of Ambae. Hospital admission was more common in males 20-29 years old. Death was a rare complication. In the face of increases in both tourism and in the global trade in tropical and exotic fish, physicians in both endemic and non-endemic areas should be familiar with the epidemiology and clinical features of this important condition. (+info)
Inclusion of immigrant status in smoking prevalence statistics.
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OBJECTIVES: Data from the 1995-1996 and 1998-1999 Current Population Survey tobacco use supplements were used to examine smoking prevalence statistics by race/ethnicity and immigrant status. METHODS: Smoking prevalence statistics were calculated, and these data were decomposed by country of birth for Asian immigrants to illustrate the heterogeneity in smoking rates present within racial/ethnic groups. RESULTS: Except in the case of male Asian/Pacific Islanders, immigrants exhibited significantly lower smoking prevalence rates than nonimmigrants. However, rates varied according to country of birth. CONCLUSIONS: This research highlights the need to disaggregate health statistics by race/ethnicity, sex, immigrant status, and, among immigrants, country of birth. Data on immigrants' health behaviors enhance the development of targeted and culturally sensitive public health smoking prevention programs. (+info)
Features of evolution and expansion of modern humans, inferred from genomewide microsatellite markers.
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We study data on variation in 52 worldwide populations at 377 autosomal short tandem repeat loci, to infer a demographic history of human populations. Variation at di-, tri-, and tetranucleotide repeat loci is distributed differently, although each class of markers exhibits a decrease of within-population genetic variation in the following order: sub-Saharan Africa, Eurasia, East Asia, Oceania, and America. There is a similar decrease in the frequency of private alleles. With multidimensional scaling, populations belonging to the same major geographic region cluster together, and some regions permit a finer resolution of populations. When a stepwise mutation model is used, a population tree based on TD estimates of divergence time suggests that the branches leading to the present sub-Saharan African populations of hunter-gatherers were the first to diverge from a common ancestral population (approximately 71-142 thousand years ago). The branches corresponding to sub-Saharan African farming populations and those that left Africa diverge next, with subsequent splits of branches for Eurasia, Oceania, East Asia, and America. African hunter-gatherer populations and populations of Oceania and America exhibit no statistically significant signature of growth. The features of population subdivision and growth are discussed in the context of the ancient expansion of modern humans. (+info)
Public health, law, and local control: destruction of the US chemical weapons stockpile.
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Destruction of US chemical weapons has begun at one of the 8 sites in the continental United States, was completed on Johnston Island in the Pacific Ocean, and is scheduled to begin in at least 3 other locations during the upcoming year. About 25% of the stockpile and 38% of the munitions had been destroyed as of December 31, 2002. However, the program has become controversial with regard to choice of technology, emergency management, and cost. This controversy is in large part due to efforts by some state and local governments and activist groups to play a more central role in a decision making process that was once fully controlled by the US Army. (+info)
Environmental threats to children's health in Southeast Asia and the Western Pacific.
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The Southeast Asia and Western Pacific regions contain half of the world's children and are among the most rapidly industrializing regions of the globe. Environmental threats to children's health are widespread and are multiplying as nations in the area undergo industrial development and pass through the epidemiologic transition. These environmental hazards range from traditional threats such as bacterial contamination of drinking water and wood smoke in poorly ventilated dwellings to more recently introduced chemical threats such as asbestos construction materials; arsenic in groundwater; methyl isocyanate in Bhopal, India; untreated manufacturing wastes released to landfills; chlorinated hydrocarbon and organophosphorous pesticides; and atmospheric lead emissions from the combustion of leaded gasoline. To address these problems, pediatricians, environmental health scientists, and public health workers throughout Southeast Asia and the Western Pacific have begun to build local and national research and prevention programs in children's environmental health. Successes have been achieved as a result of these efforts: A cost-effective system for producing safe drinking water at the village level has been devised in India; many nations have launched aggressive antismoking campaigns; and Thailand, the Philippines, India, and Pakistan have all begun to reduce their use of lead in gasoline, with resultant declines in children's blood lead levels. The International Conference on Environmental Threats to the Health of Children, held in Bangkok, Thailand, in March 2002, brought together more than 300 representatives from 35 countries and organizations to increase awareness on environmental health hazards affecting children in these regions and throughout the world. The conference, a direct result of the Environmental Threats to the Health of Children meeting held in Manila in April 2000, provided participants with the latest scientific data on children's vulnerability to environmental hazards and models for future policy and public health discussions on ways to improve children's health. The Bangkok Statement, a pledge resulting from the conference proceedings, is an important first step in creating a global alliance committed to developing active and innovative national and international networks to promote and protect children's environmental health. (+info)
T cell receptor alpha-chain polymorphic allele frequencies in Caucasians and Polynesians.
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Restriction length polymorphisms in the variable and constant regions of the T cell receptor alpha-chain were examined in 42 Caucasians, 29 Maoris and 27 Pacific Islanders. Southern blots of Taq I digested DNA were hybridized with the T cell receptor alpha-chain probe pY14. Our results confirm that a 1.4 kb T cell receptor alpha chain-Taq 1 band is allelic to a 0.5 kb band. A significant difference in the frequency of the 1.4 and 0.5 kb alleles of the variable region of the alpha-chain was detected in Caucasians when compared with Maoris or Pacific Islanders (P < 0.0001). No differences in the frequency of the 2.0 and 7.0 kb alleles of the constant region gene were detected between any of the racial groups. These data may be relevant to ethnic differences in susceptibility to immune disorders. (+info)