Relationship between heterozygosity and genetic distance in the three major races of man

In pairwise comparisons of gene frequency data from the three major races of man, the single locus measures of the heterozygosity within and the genetic distance between races are shown to be strongly correlated across the loci coding for red cell proteins and enzymes. The intercept of the regression line of genetic distance on heterozygosity in protein enzyme loci is statistically insignificant. These findings suggest that the genetic variability at the enzyme and protein loci in man is probably maintained by a balance of mutation and random genetic drift. At the blood group loci, however, the observed relationship between genetic distance and heterozygosity does not follow the expectation of the neutral mutation hypothesis. These observations are discussed in terms of the changes in probability of identical monomorphism in two populations during the process of gene differentiation.     

Pondering Poi Dog: Place and racial identification of multiracial Native Hawaiians

Given the very large proportion of Hawaiians who are multiracial, our research examines Native Hawaiian identification in mixed-race Hawaiian families. We use the 1990 US Census, which affords a unique look at racial identification because multiracial people were required to choose one race over another. The results show support for our argument that place plays a central role in Pacific identity processes, illustrated in this case among Hawaiians. We find that strong ties to Hawai‘i – the spiritual and geographic home of the Hawaiian population – are vital to the intergenerational transmission of Hawaiian identification in both continental and island multiracial families. We compare our results for multiracial Native Hawaiians to prior studies of American Indians and Asian Americans to identify any general patterns in correlates of racial identification choices. In each group, we find that familial and geographic relationships to the cultural and ancestral lands are strongly linked to racial identification.     

Racial disparities in incidence of human papillomavirus-associated oropharyngeal cancer in an urban population

BackgroundRecent studies suggest that rates of human papillomavirus related oropharyngeal cancer (HPVOPC) in the US are higher in Caucasians than minorities. We hypothesized that this disparity would be less marked in a racially and ethnically diverse population from New York City.MethodsThis is a retrospective chart review of 210 patients with biopsied or surgically treated OPC at the Icahn School of Medicine at Mount Sinai (ISMMS) between 1999 and 2013. Polymerase chain reaction (PCR) was used to detect the presence of HPV-DNA in paraffin-embedded tumor blocks. Incidence of HPV-positive cancers was compared between Caucasians and minorities (defined as African Americans, Asians, and Hispanics) using Fisher’s exact test.ResultsWe found a higher incidence of HPV-positive OPC in Caucasians than racial minorities within the ISMMS population (p = 0.002). HPV incidence detected by PCR was 139/165 [84.2%] for Caucasians and 28/45 [62.2%] for minorities. Specifically, there was a higher rate in Caucasians compared to African Americans (p = 0.017), but no significant difference between Caucasians and Hispanics (p = 0.087).ConclusionWe documented a disparity in incidence of HPVOPC amongst racial groups, consistent with previously reported trends from study populations in less urbanized areas. Thus we conclude that the factors underlying racial/ethnic disparities in HPVOPC incidence are likely to be similar across communities with different levels of urbanization and population diversity.     

Florisbad and human population succession in Southern Africa.

The human cranium recovered at Florisbad in 1932 is compared with other Sub-Saharan African hominid remains from Broken Hill, the Omo and Klasies River Mouth. The Florisbad frontal is very broad, but despite this breadth and differences in zygomatic form, there is a definite resemblance to archaic Homo sapiens from Broken Hill. There is also some similarity to both Omo I and Omo II, while fragmentary remains from Klasies River are more lightly built and hence more modern in appearance. These impressions are strengthened by measurement and statistical analysis, which demonstrates that Florisbad and Broken Hill are distant from recent African populations. Even if Florisbad is less archaic than the earlier (Middle Pleistocene?) hominid, it is not noticeably Bushman-like. New dates suggestive of early Upper Pleistocene antiquity also place Florisbad securely in a lineage containing Broken Hill, and there is no evidence to support special ties with any one group of living Africans.     

A study of some immunological and clinical characteristics of gastritis, gastric ulcer, and duodenal ulcer in three racial groups of the Venezuelan population

Circulating gastric-mucosa antibodies were found more frequently among patients with different forms of chronic gastritis than among a miscellaneous control group and groups that presented prepyloric ulcer or duodenal ulcer. A higher incidence of circulating antibodies and of chronic gastritis lesions among Caucasians and “Mestizos” than among Negroes was also observed. The latter showed a higher tendency to duodenal ulcer and prepyloric ulcer. The high incidence of gastritis and gastric ulcer of the Chinese and the Mestizos support the ethnic relation between these two human groups. Our study favors the hypothesis that genetic and ethnic factors influence, on the one hand, chronic gastritis and gastric ulcer and, on the other hand, duodenal and prepyloric ulcers.     

Amerind ancestry, socioeconomic status and the genetics of type 2 diabetes in a Colombian population

The "thrifty genotype" hypothesis proposes that the high prevalence of type 2 diabetes (T2D) in Native Americans and admixed Latin Americans has a genetic basis and reflects an evolutionary adaptation to a past low calorie/high exercise lifestyle. However, identification of the gene variants underpinning this hypothesis remains elusive. Here we assessed the role of Native American ancestry, socioeconomic status (SES) and 21 candidate gene loci in susceptibility to T2D in a sample of 876 T2D cases and 399 controls from Antioquia (Colombia). Although mean Native American ancestry is significantly higher in T2D cases than in controls (32% v 29%), this difference is confounded by the correlation of ancestry with SES, which is a stronger predictor of disease status. Nominally significant association (P<0.05) was observed for markers in: TCF7L2, RBMS1, CDKAL1, ZNF239, KCNQ1 and TCF1 and a significant bias (P<0.05) towards OR>1 was observed for markers selected from previous T2D genome-wide association studies, consistent with a role for Old World variants in susceptibility to T2D in Latin Americans. No association was found to the only known Native American-specific gene variant previously associated with T2D in a Mexican sample (rs9282541 in ABCA1). An admixture mapping scan with 1,536 ancestry informative markers (AIMs) did not identify genome regions with significant deviation of ancestry in Antioquia. Exclusion analysis indicates that this scan rules out ~95% of the genome as harboring loci with ancestry risk ratios >1.22 (at P < 0.05).     

The use of racial, ethnic, and ancestral categories in human genetics research

The global dispersal of anatomically modern humans over the past 100,000 years has produced patterns of phenotypic variation that have exerted—and continue to exert—powerful influences on the lives of individuals and the experiences of groups. The recency of our common ancestry and continued gene flow among populations have resulted in less genetic differentiation among geographically distributed human populations than is observed in many other mammalian species. Nevertheless, differences in appearance have contributed to the development of ideas about “race” and “ethnicity” that often include the belief that significant inherited differences distinguish humans. The use of racial, ethnic, and ancestral categories in genetics research can imply that group differences arise directly through differing allele frequencies, with little influence from socially mediated mechanisms. At the same time, careful investigations of the biological, environmental, social, and psychological attributes associated with these categories will be an essential component of cross-disciplinary research into the origins, prevention, and treatment of common diseases, including those diseases that differ in prevalence among groups.     

The development of genetics and population studies

The contribution of genetics and population studies to physical anthropology as reflected in the pages of our Journal is traced since its establishment in 1918. Major trends include the use of more genetic polymorphisms, the search for natural selection and genetic drift, the unraveling of population structure in a wide variety of ecological niches, and the recognition of the role of culture in human biology. Nonhuman primates have also been explored from the viewpoint of population genetic. Emphasis has been increasingly on process rather than classification.     

Holocene climate and vegetation in the Milford drainage basin,Maine, U.S.A., and their implications for human history

A 9200 ¹⁴C year fossil pollen record from a small kettle lake in central Maine, northeast U.S.A., records the development of nearby upland vegetation throughout the Archaic, Ceramic, and Historic periods of human history. The Early Archaic period (9000 to 8000 B.P.) began as open woodland dominated by Picea, Populus, and Larix, which was replaced by Pinus forest. During the Middle Archaic (8000-6000 B.P.) Tsuga-dominated forest, which developed ca. 7400 B.P., was followed by Pinus forest (ca. 6400 B.P.). The Late Archaic (6000-3000 B.P.) was a period of great transition; Tsuga forest developed again ca. 5700 B.P., but was abruptly replaced by northern hardwood forest ca. 4700 B.P. That Late Archaic expansion of hardwoods would have provided better forage for beaver. Coincidentally, boreal wetland mammals such as beaver (Castor canadensis) and muskrat (Ondatra zibethicus) increase in faunal assemblages of local archaeological sites, while remains of anadromous fish decrease. We postulate that the apparent increase in human populations throughout the region during the Late Archaic may be attributed to an increase in the resource base within both upland and wetland areas resulting from the development of hardwood forest in response to climatic cooling.     

The force of selection on the human life cycle

In this article, I present evidence for a robust and quite general force of selection on the human life cycle. The force of selection acts in remarkably invariant ways on human life histories, despite a great abundance of demographic diversity. Human life histories are highly structured, with mortality and fertility changing substantially through the life cycle. This structure necessitates the use of structured population models to understand human life history evolution. Using such structured models, I find that the vital rates to which fitness is most sensitive are prereproductive survival probabilities, particularly the survival of children ages 0 to 4 years. The fact that the preponderance of selection falls on transitions related to recruitment combined with the late age at first reproduction characteristic of the human life cycle creates a fitness bottleneck out of recruitment. Because of this, antagonistic pleiotropy with any trait that detracts from the constituent transitions to recruitment is expected. I explore the predictors of variation in the force of selection on early survival. High fertility increases the selective premium placed on early survivorship, whereas high life expectancy at birth decreases it.     

云南纵坑切梢小蠹四个地理种群同工酶比较研究

采用不连续聚丙烯酰胺凝胶电泳技术研究了纵坑切梢小蠹（Ｔｏｍ ｉｃｕｓ ｐｉｎｉｐｅｒｄａ Ｌ．）４ 个自然种群的９ 个同工酶基因座。４ 个种群均在Ｅｓ－ １、Ｅｓ－ ２、Ｅｓ－ ４、Ｍｄｈ－ １、Ｍｄｈ－ ２ 及ＡＡＴ－ １ 基因座上存在遗传多态现象。路南长湖、楚雄、蒙自３ 种群间的遗传距离为０．００３６～０．０１７３, 平均值为０．０１０５, 表明其遗传结构基本相似。丽江种群与上述３ 种群之间的遗传距离为０．１４２１～０．２０３５, 平均值为０．１７６５,表明丽江种群与上述三种群已有了遗传分化。丽江种群近交系数较大,近亲繁殖程度较高。种群遗传结构的差异可能与不同蠹害程度之间存在一定的内在联系。     

群体遗传学研究中的数据处理方法I．RAPD数据的AMOVA分析

近年来,RAPD数据和AMOVA分析广泛地应用于群体遗传学和保护遗传学研究。然而,由于RAPD标记具显性特点。加上目前进行AMOVA分析所依赖的RAPDistance软件不完善,使得对RAPD数据进行AMOVA分析时存在许多不足。本文介绍了AMOVA分析的基本过程,同时引入一个新的程序DCFA用以替代RADistance并详述了将DCFA与WINAMOVA联用,对RAPD数据进行AMOVA分析的具体步骤与注意事项,最后,以产自中国和巴西8个普通野生稻（Oryza furipogon)天然群体为例,演示了对RAPD表型数据进行AMOVA分析的过程,讨论了AMOVA分析结果在群体遗传结构上的意义。通过对AMOVA算法的分析,同时比较4种距离系数所得AMOVA结果,我们认为在进行AMOVA分析时选择NEI－LI距离和欧氏距离平方较为合适,而目前国内使用较多的JACCARD系数不适合AMOVA分析。     

Admixture and skin color in the transplanted Tlaxcaltecan population of Saltillo,Mexico

Ethnohistoric accounts and serological analyses have documented the genetic effects of transplantation and admixture of several subpopulations of Tlaxcaltecans in Saltillo, Mexico. Interpopulational affinities are assessed using skin reflectance readings taken at the upper inner arm site with a Photovolt Model 670 reflectance spectrophotometer for these groups, focusing on the barrios of La Minita and Chamizal. Genetic distance analyses based on blood groups and skin reflectance data are in close agreement and reflect differential rates of admixture for these groups. Admixture estimates for a dihybrid model (Indian-Spanish) were derived from skin reflectances and show a slight tendency for underestimation of Spanish admixture when compared to blood group estimates. Application of a trihybrid model incorporating West African admixture shows similar estimates based on blood groups, immunoglobulins, and skin color.     

The adaptive legacy of human evolution: A search for the environment of evolutionary adaptedness

The growth of evolutionary psychology has led to renewed interest in what might be the significant evolutionary heritage of people living today, and in the extent to which humans are suited to a particular adaptive environment—the EEA. The EEA, though, is a new tool in the battery of evolutionary concepts, and it is important both that it is scrutinized for its utility, and that the actual reconstructions of the environments in which humans and hominids evolved are based on sound palaeobiological inference and an appropriate use of the phylogenetic context of primate evolution.     

Use of DNA fingerprinting for human population genetic studies

DNA fingerprinting techniques have been used in population genetic studies on many different kinds of organisms. Here, we present new applications for multilocus DNA fingerprint probes in population studies and demonstrate the applicability of DNA fingerprinting to human population genetics, using M13 phage DNA as a probe. The new approach, which is based on a factor method of numerical coding of non-quantitative data (factor correspondence analysis-FCA), shows good agreement between population position, as indicated by the three principal factors, and ethnogenetic proximity.     

Phylogeography, population history and conservation genetics of jaguars (Panthera onca, Mammalia, Felidae)

The jaguar (Panthera onca), the largest felid in the American Continent, is currently threatened by habitat loss, fragmentation and human persecution. We have investigated the genetic diversity, population structure and demographic history of jaguars across their geographical range by analysing 715 base pairs of the mitochondrial DNA (mtDNA) control region and 29 microsatellite loci in approximately 40 individuals sampled from Mexico to southern Brazil. Jaguars display low to moderate levels of mtDNA diversity and medium to high levels of microsatellite size variation, and show evidence of a recent demographic expansion. We estimate that extant jaguar mtDNA lineages arose 280 000-510 000 years ago (95% CI 137 000-830 000 years ago), a younger date than suggested by available fossil data. No strong geographical structure was observed, in contrast to previously proposed subspecific partitions. However, major geographical barriers such as the Amazon river and the Darien straits between northern South America and Central America appear to have restricted historical gene flow in this species, producing measurable genetic differentiation. Jaguars could be divided into four incompletely isolated phylogeographic groups, and further sampling may reveal a finer pattern of subdivision or isolation by distance on a regional level. Operational conservation units for this species can be defined on a biome or ecosystem scale, but should take into account the historical barriers to dispersal identified here. Conservation strategies for jaguars should aim to maintain high levels of gene flow over broad geographical areas, possibly through active management of disconnected populations on a regional scale.     

A popular misapplication of evolutionary modeling to the study of human cooperation

To examine the evolutionary basis of a behavior, an established approach (known as the phenotypic gambit) is to assume that the behavior is controlled by a single allele, the fitness effects of which are derived from a consideration of how the behavior interacts, via life-history, with other ecological factors. Here we contrast successful applications of this approach with several examples of an influential and superficially similar line of research on the evolutionary basis of human cooperation. A key difference is identified: in the latter line of research the focal behavior, cooperation, is abstractly defined in terms of immediate fitness costs and benefits. Selection is then assumed to act on strategies in an iterated social context for which fitness effects can be derived by aggregation of the abstractly defined immediate fitness effects over a lifetime. This approach creates a closed theoretical loop, rendering models incapable of making predictions or providing insight into the origin of human cooperation. We conclude with a discussion of how evolutionary approaches might be appropriately used in the study of human social behavior.