Palaeo-Eskimo genetic ancestry and the peopling of Chukotka and North America.

Much of the American Arctic was first settled 5,000 years ago, by groups of people known as Palaeo-Eskimos. They were subsequently joined and largely displaced around 1,000 years ago by ancestors of the present-day Inuit and Yup'ik1-3. The genetic relationship between Palaeo-Eskimos and Native American, Inuit, Yup'ik and Aleut populations remains uncertain4-6. Here we present genomic data for 48 ancient individuals from Chukotka, East Siberia, the Aleutian Islands, Alaska, and the Canadian Arctic. We co-analyse these data with data from present-day Alaskan Iñupiat and West Siberian populations and published genomes. Using methods based on rare-allele and haplotype sharing, as well as established techniques4,7-9, we show that Palaeo-Eskimo-related ancestry is ubiquitous among people who speak Na-Dene and Eskimo-Aleut languages. We develop a comprehensive model for the Holocene peopling events of Chukotka and North America, and show that Na-Dene-speaking peoples, people of the Aleutian Islands, and Yup'ik and Inuit across the Arctic region all share ancestry from a single Palaeo-Eskimo-related Siberian source.

Racial misclassification of American Indians and Alaska Natives by Indian Health Service Contract Health Service Delivery Area.

OBJECTIVES: We evaluated the racial misclassification of American Indians and Alaska Natives (AI/ANs) in cancer incidence and all-cause mortality data by Indian Health Service (IHS) Contract Health Service Delivery Area (CHSDA). METHODS: We evaluated data from 3 sources: IHS-National Vital Statistics System (NVSS), IHS-National Program of Cancer Registries (NPCR)/Surveillance, Epidemiology and End Results (SEER) program, and National Longitudinal Mortality Study (NLMS). We calculated, within each data source, the sensitivity and classification ratios by sex, IHS region, and urban-rural classification by CHSDA county. RESULTS: Sensitivity was significantly greater in CHSDA counties (IHS-NVSS: 83.6%; IHS-NPCR/SEER: 77.6%; NLMS: 68.8%) than non-CHSDA counties (IHS-NVSS: 54.8%; IHS-NPCR/SEER: 39.0%; NLMS: 28.3%). Classification ratios indicated less misclassification in CHSDA counties (IHS-NVSS: 1.20%; IHS-NPCR/SEER: 1.29%; NLMS: 1.18%) than non-CHSDA counties (IHS-NVSS: 1.82%; IHS-NPCR/SEER: 2.56%; NLMS: 1.81%). Race misclassification was less in rural counties and in regions with the greatest concentrations of AI/AN persons (Alaska, Southwest, and Northern Plains). CONCLUSIONS: Limiting presentation and analysis to CHSDA counties helped mitigate the effects of race misclassification of AI/AN persons, although a portion of the population was excluded.

Blood politics, ethnic identity, and racial misclassification among American Indians and Alaska Natives.

Misclassification of race in medical and mortality records has long been documented as an issue in American Indian/Alaska Native data. Yet, little has been shared in a cohesive narrative which outlines why misclassification of American Indian/Alaska Native identity occurs. The purpose of this paper is to provide a summary of the current state of the science in racial misclassification among American Indians and Alaska Natives. We also provide a historical context on the importance of this problem and describe the ongoing political processes that both affect racial misclassification and contribute to the context of American Indian and Alaska Native identity.

Including self-reported race to improve cancer surveillance data for American Indians and Alaska Natives in Washington state.

BACKGROUND: American Indians and Alaska Natives (AI/AN) are frequently misclassified as another race in cancer surveillance systems, resulting in underestimated morbidity and mortality. Linkage methods with administrative records have been used to correct AI/AN misclassification, but AI/AN populations living in urban areas, and those who self-identify as AI/AN race, continue to be under-ascertained. The aim of this study was to evaluate racial misclassification in two cancer registries in Washington State using an urban AI/AN patient roster linked with a list of Indian Health Service (IHS) enrollees. METHODS: We conducted probabilistic record linkages to identify racial misclassification using a combined demographic dataset of self-identified AI/AN patients of a large, urban Indian health center, and administratively-identified AI/AN enrolled with the IHS. Age-adjusted incidence rates were calculated for 3 linkage populations: AI/ AN originally coded in each cancer registry, post-linkage AI/AN identified through the IHS roster alone, and post-linkage AI/AN identified through either the urban or IHS file. RESULTS: In the state and regional cancer registries, 11% and 18%, respectively, of matched cases were originally coded as a race other than AI/AN; approximately 35% of these were identified by the urban file alone. Incidence rate estimates increased after linkage with the IHS file, and further increased with the addition of urban records. Matches identified by the urban patient file resulted in the largest relative incidence change being demonstrated for King County (which includes Seattle); the all-site invasive cancer rate increased 8.8%, from 443 to 482 per 100,000. CONCLUSIONS: Inclusion of urban and self-identified AI/AN records can increase case ascertainment in cancer surveillance systems beyond linkage methods using only administrative sources.

Effect of race and ethnicity classification on survey estimates: Anomaly of the weighted totals of American Indians and Alaska Natives.

Racial classification is a paramount concern in data collection and analysis for American Indians and Alaska Natives (AI/ANs) and has far-reaching implications in health research. We examine how different racial classifications affect survey weights and consequently change health-related indicators for the AI/AN population in California. Using a very large random population-based sample of AI/ANs, we compared the impact of three weighting strategies on counts and rates of selected health indicators. We found that different weights examined in this study did not change the percentage estimates of health-related variables for AI/ANs, but did influence the population total estimates dramatically. In survey data, different racial classifications and tabulations of AI/ANs could yield discrepancies in weighted estimates for the AI/AN population. Policy makers need to be aware that the choice of racial classification schemes for this racial-political group can generally influence the data they use for decision making.

Paleo-Eskimo mtDNA genome reveals matrilineal discontinuity in Greenland.

The Paleo-Eskimo Saqqaq and Independence I cultures, documented from archaeological remains in Northern Canada and Greenland, represent the earliest human expansion into the New World's northern extremes. However, their origin and genetic relationship to later cultures are unknown. We sequenced a mitochondrial genome from a Paleo-Eskimo human by using 3400-to 4500-year-old frozen hair excavated from an early Greenlandic Saqqaq settlement. The sample is distinct from modern Native Americans and Neo-Eskimos, falling within haplogroup D2a1, a group previously observed among modern Aleuts and Siberian Sireniki Yuit. This result suggests that the earliest migrants into the New World's northern extremes derived from populations in the Bering Sea area and were not directly related to Native Americans or the later Neo-Eskimos that replaced them.

Office of Management and Budget racial categories and implications for American Indians and Alaska Natives.

This commentary provides a brief overview of American Indian and Alaskan populations in the United States and selected data issues. The focus of this commentary is an excerpt of recommendations related to Office of Management and Budget Directive 15 (racial categories) and American Indians and Alaska Natives. Of paramount concern is not only that all federal, state, and local agencies collect data on American Indians and Alaska Natives, but also that reports, findings, and peer-reviewed publications include data on American Indians and Alaska Natives. It is of no use to recruit American Indians and Alaska Natives into studies and projects if their race/ethnicity-specific data are not disseminated. Collapsing racial/ethnic categories, such as Asians, Native Hawaiians and Pacific Islanders, and American Indians and Alaska Natives, into a single racial category of "other" is of no benefit to public health policymakers, researchers, and tribal planners. Likewise, tribal affiliation should be collected whenever it is feasible to do so. Insufficient inclusion and inaccurate identification of American Indians and Alaska Natives in national surveys has also resulted in a dearth of baseline data in significant reports such as Healthy People 2010.

Heterochronic quantitative microevolution: dental divergence in aboriginal Americans.

Studies of tooth crown morphology alone have proven valuable in defining human population differentiation. We test the hypothesis that quantitative comparisons of more complex whole tooth structure may prove informative in understanding human diversity. Three disparate populations in Native American genetic history were compared: Kodiak Island Western Eskimos, Peruvian Inca Amerindians, and Southeast Asians. Enamel depth (an increasing gradient extended from Southeast Asians to the Inca) and root parameters were the most discriminating variables. The observed microevolution appears to result from variation in timing of known X-linked, Y-linked, and autosomal genes that affect either ameloblast or odontoblast differentiation. The dental traits were sexually dimorphic, the effect being more pronounced in aboriginal Americans, with male teeth having robust roots and thin enamel compared to female. Southeast Asians were isometrically related. The prominence of sexual dimorphism and the importance of sex-linked genes in the determination of the dental phenotypes suggest that sexual selection was one evolutionary force acting on early Asian populations. Subsequently, the selection appears to have been relaxed in Southeast Asians. Observed divergence of tooth shape among the populations, i.e., differences in the appropriation process of tooth primordia, was mainly the consequence of genetic drift modulating heterochronic regulators of homeotic genes.

Correctness of racial coding of American Indians and Alaska Natives on the Washington State death certificate.

Underestimation of death rates for specific races can obscure health problems and impair the ability of public programs to prevent premature death and disability. For accurate race-specific death rates, the racial classification of both the population at risk and the decreased population must be accurately ascertained. However, studies suggest that the American Indian (AI) and Alaska Native (AN) races may be not be accurately recorded on the death certificate. We performed a computerized linkage between the Indian Health Service (IHS) patient registry and the 1985-1990 computerized Washington State death certificate data. The deceased was correctly identified as AI or AN on the death certificate for 1,088 (87.2%) of 1,248 matched deaths. The majority (93%) of deceased persons identified on the death certificate as not AI or AN were listed as white. The percentage of American Indian ancestry was strongly associated with correct racial classification on the death certificate (P < .001). Birth in Washington State, membership in a large Washington State tribe, and death from an alcohol condition independently added to the likelihood of correct AI or AN racial classification. Persons who died from cancer were significantly less likely to be correctly coded as AI or AN on the death certificate.

The HLA system in Inupiat and Central Yupik Alaskan Eskimos.

We have studied HLA antigen profiles of the Inupiaq and Yupik-speaking peoples, two of the four Eskimo linguistic groups residing in Alaska. A relatively restricted polymorphism of HLA-A and -B locus antigens was noted. Only 35% of A locus specificities and 37% of B locus specificities tested for were detected in each population. The most common A locus alleles were A2, A24, and A28; the most common B locus alleles were B51(5), B27, B35, Bw60(40), Bw61(40), and Bw62(15). The antigens Cw3 (75 and 69%) and DR4 (81 and 67%) were found in high frequency in both groups. HLA-DR1, DR2, and DR7 were detected infrequently, while DR3 was not detected at all. DR4 was frequently associated in both Inupiats and Yupiks with Dw4, a specificity that was thought to occur only in Caucasian populations. A statistically significant difference between Inupiats and Yupiks was found for polymorphism at the A locus, but no significant differences were found for polymorphisms at the B, C, D, or DR loci. Analysis of HLA linkage disequilibrium revealed the presence of several novel haplotypes not previously described in other populations, suggesting that the selective factors responsible for positive associations observed in these Native Alaskans were probably distinct.