Human Biology

Human Biology 73.4, August 2001

Articles

    Martínez-Cruzado, J. C.
    Toro-Labrador, G.
    Ho-Fung, V.
    Estévez-Montero, M.
    Lobaina-Manzanet, A.
    Padovani-Claudio, D. A.
    Sánchez-Cruz, H.
    Ortiz-Bermúdez, P.
    Sánchez-Crespo, A.
  • Mitochondrial DNA Analysis Reveals Substantial Native American Ancestry in Puerto Rico
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    Subject Headings:
    • Human population genetics -- Puerto Rico.
    • Taino Indians -- Puerto Rico.
    • Mitochondrial DNA -- Puerto Rico.
    Abstract:
      To estimate the maternal contribution of Native Americans to the human gene pool of Puerto Ricans--a population of mixed African, European, and Amerindian ancestry--the mtDNAs of two sample sets were screened for restriction fragment length polymorphisms (RFLPs) defining the four major Native American haplogroups. The sample set collected from people who claimed to have a maternal ancestor with Native American physiognomic traits had a statistically significant higher frequency of Native American mtDNAs (69.6%) than did the unbiased sample set (52.6%). This higher frequency suggests that, despite the fact that the native Taíno culture has been extinct for centuries, the Taíno contribution to the current population is considerable and some of the Taíno physiognomic traits are still present. Native American haplogroup frequency analysis shows a highly structured distribution, suggesting that the contribution of Native Americans foreign to Puerto Rico is minimal. Haplogroups A and C cover 56.0% and 35.6% of the Native American mtDNAs, respectively. No haplogroup D mtDNAs were found. Most of the linguistic, biological, and cultural evidence suggests that the Ceramic culture of the Taínos originated in or close to the Yanomama territory in the Amazon. However, the absence of haplogroup A in the Yanomami suggests that the Yanomami are not the only Taíno ancestors.
    Keywords:
      native american MTDNA haplogroups, taínos, historical migration
    Flores, Carlos.
    Maca-Meyer, Nicole.
    Pérez, José A.
    Hernández, Mariano.
    Cabrera, Vicente M.
  • Y-Chromosome Differentiation in Northwest Africa
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    Subject Headings:
    • Human population genetics -- Africa, Northwest.
    • Y chromosome.
    • Genetic markers -- Africa, Northwest.
    Abstract:
      Variation of seven Y-chromosomal DNA polymorphisms, one microsatellite (DYS19), and six biallelic markers (DYS287, DYS271, SRY-2627, SRY-1532, 92R7, and M9), were studied in males from Northwest Africa. To evaluate the degree of differentiation in this region, males from neighboring areas such as the Iberian Peninsula and sub-Saharan Africa were also typed. The results show a large number of paternal lineages of Northwest African origin (over 75%), supporting a long-term population continuity in the area. When the analysis of molecular variance (AMOVA) was performed both on the microsatellite and biallelic marker combinations or haplogroups, a large degree of differentiation among areas was revealed. In spite of these geographic differences, some gene flow between areas was detected by the presence of haplogroups with other geographical origins.
    Keywords:
      biallelic markers, microsatellites, haplotypes, Iberian Peninsula, Sub-Sahara
    Hegele, Robert A.
    Ban, Matthew R.
    Carrington, Christine V.
    Ramdath, D. Dan.
  • Allele Frequencies for Candidate Genes in Atherosclerosis and Diabetes among Trinidadian Neonates
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    Subject Headings:
    • Infants (Newborn) -- Trinidad and Tobago.
    • Human population genetics -- Trinidad and Tobago.
    Abstract:
      Trinidadians of South Asian origin have a high prevalence of cardiovascular disease and diabetes compared to Trinidadians of African origin. The degree to which these differences are related to genetic and/or environmental factors is unclear. To determine whether there might be a genetic basis for this difference in prevalence of deleterious phenotypes we examined allele frequencies for candidate genes in atherosclerosis and diabetes. We genotyped 81 consecutive neonates of African origin and 103 consecutive neonates of South Asian origin. We evaluated common polymorphisms in 11 candidate genes for atherosclerosis and diabetes. We found differences between the two subpopulations in the allele frequencies of several candidate genes, including APOE, LIPC, APOC3, PON1, PON2, and PPP1R3. However, the differences in the allele frequencies were not all consistent with the pattern of CHD expression between these two ethnic groups in adulthood. Thus, differences in genetic architecture alone may not explain the wide disparities in disease prevalence between these two subpopulations. It is very likely that environmental factors, or unmeasured genetic factors, influence the genetic susceptibility to disease in these subpopulations.
    Keywords:
      lipids, hypertension, polygenic disease
    Agarwala, Richa.
    Schäffer, Alejandro A.
    Tomlin, James F.
  • Towards a Complete North American Anabaptist Genealogy II: Analysis of Inbreeding
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    Subject Headings:
    • Anabaptists -- North America.
    • Inbreeding -- North America.
    Abstract:
      We describe a large genealogy data base, which can be searched by computer, of 295,095 Amish and Mennonite individuals. The data base was constructed by merging our existing Anabaptist Genealogy Database 2.0 containing approximately 85,000 individuals with a genealogy file containing approximately 242,000 individuals, kindly provided by Mr. James Hostetler. The merging process corrected thousands of inconsistencies and eliminated hundreds of duplicate individuals. Geneticists have long been interested in Anabaptist populations because they are closed and have detailed written genealogies. The creation of an enlarged and unified data base affords the opportunity to examine inbreeding trends and correlates in these populations. We show the following results. The frequency of consanguineous marriages shows steady increase over time and reached approximately 85% for individuals born in 1940-1959. Among consanguineous marriages, the median kinship coefficient stayed stable in the 19th century, but rose from 0.0115 to 0.0151 in the 20th century. There are statistically significant associations (p < 0.0001) between inbreeding and family size and interbirth intervals in the 20th century. There is an association (p < 0.0005) between inbreeding and early death for individuals born in 1920-1959. However, this association reverses dramatically (p < 0.0005 in the opposite direction) for individuals born in 1960-1979. We tested for an association between inbreeding and being the mother of twins, but found none.
    Keywords:
      Amish, Mennonite, genealogy, inbreeding coefficient, kinship coefficient, isolated populations
    Sánchez-Sellero, C.
    Fariña, J.
    Aínsua, R. L.
    Varela, T. A.
  • Local Differences in the Archbishopric of Santiago de Compostela (Galicia, Spain) in Relation to the Consanguinity Structure, 1900-1979
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    Subject Headings:
    • Consanguinity -- Spain -- Galicia (Region)
    • Catholic Church. Diocese of Santiago de Compostela (Spain)
    Abstract:
      The microgeographic variability of consanguinity in the Archbishopric of Santiago de Compostela (Galicia) between 1900 and 1979 was studied. This Archbishopric covers 106 local councils integrated by 964 parishes, of which 677 (70.23%) were analyzed. Of the 307,094 marriages counted within this period, 15,739 corresponded to weddings between biologically related couples. Within the Archbishopric, eight geographical regions were considered: six coastal regions (Golfo Artabro, Bergantiños, Fisterra, Xallas, Santiago Oeste, and Rías Baixas) and two inland regions (Santiago Este and Terra de Montes). In order to evaluate the differences and similarities among them, the frequencies of all types of marriages (consanguineous and nonconsanguineous) were considered. First, a hierarchical grouping of the regions based on their chi-squared distances was performed. Then, in order to analyze relationships that are exclusively due to the structure of consanguinity, a correspondence analysis was performed and only the frequency of the different types of consanguineous marriages was taken into account. The results from both statistical analyses indicate special features of the Xallas region, both in the level of inbreeding (8.75%, the highest in the Archbishopric) and in the structure of consanguinity, for which a high proportion of uncle-niece marriages was found (6.22% of all consanguineous marriages). In all cases the structure of consanguinity provides informative nuances on the differences and similarities among population groups.
    Keywords:
      inbreeding, structure of consanguinity, population distance, hierarchical grouping, correspondence analysis
    Luna, F.
    Polo, V.
    Fernandez-Santander, A.
    Moral, P.
  • Stillbirth Pattern in an Isolated Mediterranean Population: La Alpujarra, Spain
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    Subject Headings:
    • Stillbirth -- Spain -- Alpujarra Region.
    Abstract:
      This study attempted to analyze the effect of several factors on the stillbirth pattern in a relatively isolated rural population, La Alpujarra (Spain), during the first half of the 20th century. The study was a retrospective analysis from a total sample of 2199 births to 525 mothers, allowing for birth year of mother, maternal age, parental inbreeding, family size, birth order, sex, single/twin delivery, and birth interval. Binomial probability distribution of stillbirths provided no evidence for any significantly increased risk in relation to family size. Analysis of covariance (ANCOVA) of stillbirth risk in affected families indicated a significant effect for sex of the child, parental consanguinity, and birth year of mother. Logistic regression showed increased risk in twin delivery and pregnancy order one, but not for birth order other than one. Multivariate analysis of variance (MANOVA) testing for differences between affected and unaffected families supported a temporal decrease of stillbirths during the period studied. Although the birth interval average was significantly shorter in affected families (p < 0.0001), this association did not hold, in a more detailed analysis, for individual intervals in these families (p = 0.20). There was no significant effect of maternal age on stillbirths in the whole sample or limited to first pregnancies. These results suggest that birth order one and twin delivery were the main determinants of the stillbirth pattern in La Alpujarra. Furthermore, our data indicate that the decline in stillbirth rate began before medical facilities for perinatal care became available, which was not until after 1950. The temporal decrease in stillbirth rates may therefore be related to an increasing social attention to deliveries rather than to prenatal care medical facilities.
    Keywords:
      inbreeding, parity, maternal age, twinning, sanitary conditions

Brief Communications

    Demarchi, Darío A.
    Panzetta-Durtari, Graciela M.
    Colantonio, Sonia.
    Marcellino, Alberto J.
  • Absence of the 9-bp Deletion of Mitochondrial DNA in Pre-Hispanic Inhabitants of Argentina
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    Subject Headings:
    • Mitochondrial DNA -- Argentina.
    • Indians of South America -- Argentina.
    Abstract:
      We investigated the incidence of the Region V mitochondrial DNA 9-base-pair (bp) deletion from human remains recovered from several archaeological sites and contexts throughout Argentina. Of the 34 samples analyzed, 24 yielded DNA extractions that gave clear amplification results. All of the individuals carried two repeats of the 9 bp, one of which has been shown to be deleted in some individuals of Asian origin and defines mitochondrial lineage B. Although most of the modern Amerindian groups in the region exhibit the deletion in high frequencies, the absence of the 9-bp deletion among ancient populations of South America seems to be the rule rather than the exception, as was reported by several studies involving extinct populations. The evidence gathered until now suggests that the earliest settlers of this region of South America did not carry mitochondrial lineage B.
    Keywords:
      adna, amerindians
    Hoff, Charles.
    Thorneycroft, Ian.
    Wilson, Felicia.
    Williams-Murphy, Monica.
  • Protection Afforded by Sickle-Cell Trait (Hb AS): What Happens when Malarial Selection Pressures Are Alleviated?
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    Subject Headings:
    • Fertility, Human -- Alabama -- Mobile.
    • African American women -- Alabama -- Mobile.
    • Sickle cell anemia.
    Abstract:
      A study of reproductive outcome in Mobile, AL was conducted among a large maternal cohort with sickle-cell disease (Hb SS), sickle-cell trait (Hb AS), and no hemoglobinopathies (Hb AA). It was found that mean gravidity and live births among Hb AS women were significantly higher than among Hb AA women. These findings were surprising since it is generally held that once malarial pressure is alleviated, any reproductive advantage that might be conferred by Hb AS would disappear and fertility levels would reach levels similar to or slightly less than that of Hb AA women. A search of the literature was subsequently conducted and a large cohort study of an African-derived population was found in the United Kingdom. Results from this study also showed that parity was significantly higher among Hb AS women compared to Hb AA women. If survivorship is similar among Hb AS and Hb SS women, findings from these two studies raise doubts whether directional selection is occurring against the Hb S allele in nonmalarial environments. Balancing selection may still be occurring.
    Keywords:
      sickle-cell trait, fertility, selection
    Alcântara, Vânia M.
    Rodrigues, Luciane C.
    Oliveira, Lisangela C.
    Chautard-Freire-Maia, Eleidi A.
  • Association of the CHE2 Locus with Body Mass Index and Butyrylcholinesterase Activity
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    Subject Headings:
    • Body weight -- Brazil -- Curitiba.
    • Cholinesterases.
    • Phenotype -- Brazil -- Curitiba.
    Abstract:
      The butyrylcholinesterase (BChE; EC 3.1.1.8) activities of two electrophoretic bands of the CHE2 C5+ phenotype--C5 and COF (other forms)--were quantified by densitometry in 100 individuals. The activity data suggested that, in addition to determining C5, the CHE2*C5+ allele also increases the level of other BChE forms. Since the relative activity of C5 showed the highest correlation coefficient with weight when compared with the other BChE activity variables (total, absolute C5, and absolute COF), its median activity level was used for the classification of CHE2 C5+ phenotypes (faint and intense). Mean body mass index (BMI) was compared among the CHE2 locus phenotypes--controlled by sex, age, and ethnic group. It was shown that the intense CHE2 C5+ phenotype presents a significantly lower (p < 0.001) mean BMI (23.2) than the other phenotypes (faint CHE2 C5+ = 25.2; CHE2 C5- = 25.4). It seems that the relative COF activity is positively associated with fat storage, since CHE2 C5- and faint CHE2 C5+ phenotypes showed higher mean BMI than the intense CHE2 C5+ phenotype. Our hypothesis is that the presence of C5 in a relatively high proportion leads to less fat storage.
    Keywords:
      serum cholinesterase, CHE2 C5+ phenotype, BMI, BCHE activity, human weight
    Hampshire, K. R.
    Smith, Malcolm T.
  • Consanguineous Marriage among the Fulani
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    Subject Headings:
    • Fula (African people) -- Burkina Faso.
    • Consanguinity -- Burkina Faso.
    Abstract:
      The Fulani are a broad ethnic category of nomadic and seminomadic pastoralists and agropastoralists living in the semiarid Sahel region of sub-Saharan Africa. The Fulani are patrilineal, patrilocal, and moderately polygynous, with arranged first marriages accompanied by the payment of bridewealth, ideally in the form of cattle. Consanguineous marriage is frequent, with first or second cousin marriage preferred. In this paper we present data on levels of consanguineous marriage among the Fulani of northern Burkina Faso and test the hypothesis that inbreeding may be more frequent when there is a scarcity of cattle available, since bridewealth demands are thought to be reduced with close-kin marriage. Among 308 women's marriages, 203 (65.8%) were between kin up to and including second cousins, and 102 (33.1%) were between nonkin. Among 276 men's marriages, 196 (71.0%) were between kin up to and including second cousins, and 77 (27.9%) were between nonkin. The mean population inbreeding coefficient (a) was 0.0355 for women, and 0.0374 for men. No increase was found in population levels of inbreeding estimated from marriages contracted after the droughts of 1973 and 1984, which drastically reduced the Fulani's cattle stocks. However, a significantly higher rate of consanguineous marriage was found in families owning the fewest cattle.
    Keywords:
      consanguinuity, inbreeding, pastoralists, bridewealth
    Campbell, R. B.
  • John Graunt, John Arbuthnott, and the Human Sex Ratio
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    Subject Headings:
    • Graunt, John, 1620-1674. Natural and political observations made upon the bills of mortality.
    • Arbuthnott, John. Argument for divine providence, taken from the constant regularity observ'd in the births of both sexes.
    • Sex ratio.
    Abstract:
      John Graunt was the first person to compile data that showed an excess of male births over female births. He also noticed spatial and temporal variation in the sex ratio, but the variation in his data is not significant. John Arbuthnott was the first person to demonstrate that the excess of male births is statistically significant. He erroneously concluded that there is less variation in the sex ratio than would occur by chance, and asserted without a basis that the sex ratio would be uniform over all time and space.
    Keywords:
      sex ratio, history of statistics

Book Reviews

    Landau, Misia, 1953-
  • The Origins of Life: From the Birth of Life to the Origin of Language (review)
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    Subject Headings:
    • Maynard Smith, John, 1920- Origins of life: from the birth of life to the origin of language.
    • Szathmáry, Eörs.
    • Evolution (Biology)
    Parra, Esteban J.
  • Migration and Colonization in Human Microevolution (review)
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    Subject Headings:
    • Fix, Alan G. Migration and colonization in human microevolution.
    • Human population genetics.



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