Surnames in the Azores: analysis of the isonymy structure

Geographic isolation is a significant factor to consider when characterizing human populations. The knowledge of the genetic structure of isolated populations has been of great importance to disease-locus positioning and gene identification. To investigate the genetic structure of the Azorean population, we conducted a survey based on the frequencies of surnames listed in the 2001 telephone book. We calculated the following parameters: isonymy (I), the random component of inbreeding (F(ST)), genetic diversity according to Fisher (alpha), Karlin-McGregor's migration rate (v), and Nei's distance. For the 1,271 subscribers and 163 different surnames, Graciosa island presented the lowest value of abundance of surnames (alpha = 15.75), suggesting great genetic isolation compared to the other eight islands. Migration, calculated on the basis of the diversity of surnames within islands, ranged from 0.2747 (Corvo island) to 0.0026 (S?o Miguel island), indicating that people migrated preferentially toward the economically more developed islands. The value of the random component of inbreeding obtained for the whole population (F(ST) = 0.0039) indicates little genetic differentiation (Wright's F(ST) < 0.05). Moreover, isonymy similarity revealed using the UPGMA method shows three subclusters corresponding to the geographic distribution of the islands.     

Temporal trends in severe malaria in Chittagong, Bangladesh

ABSTRACT: BACKGROUND: Epidemiological data on malaria in Bangladesh are sparse, particularly on severe and fatal malaria. This hampers the allocation of healthcare provision in this resource-poor setting. Over 85% of the estimated 150,000-250,000 annual malaria cases in Bangladesh occur in Chittagong Division with 80% in the Chittagong Hill Tracts (CHT). Chittagong Medical College Hospital (CMCH) is the major tertiary referral hospital for severe malaria in Chittagong Division. METHODS: Malaria screening data from 22,785 inpatients in CMCH from 1999-2011 were analysed to investigate the patterns of referral, temporal trends and geographical distribution of severe malaria in Chittagong Division, Bangladesh. RESULTS: From 1999 till 2011, 2,394 malaria cases were admitted, of which 96% harboured Plasmodium falciparum and 4% Plasmodium vivax. Infection was commonest in males (67%) between 15 and 34 years of age. Seasonality of malaria incidence was marked with a single peak in P. falciparum transmission from June to August coinciding with peak rainfall, whereas P. vivax showed an additional peak in February-March possibly representing relapse infections. Since 2007 there has been a substantial decrease in the absolute number of admitted malaria cases. Case fatality in severe malaria was 18% from 2008-2011, remaining steady during this period. A travel history obtained in 226 malaria patients revealed only 33% had been to the CHT in the preceding three weeks. Of all admitted malaria patients, only 9% lived in the CHT, and none in the more remote malaria endemic regions near the Indian border. CONCLUSIONS: The overall decline in admitted malaria cases to CMCH suggests recent control measures are successful. However, there are no reliable data on the incidence of severe malaria in the CHT, the most endemic area of Bangladesh, and most of these patients do not reach tertiary health facilities. Improvement of early treatment and simple supportive care for severe malaria in remote areas and implementation of a referral system for cases requiring additional supportive care could be an important component of further reducing malaria-attributable disease and death in Bangladesh.     

Marriage structure of Yakut populations: Ethnic composition and isonymy inbreeding

Marriage structure has been analyzed in the populations of the administrative centers of five uluses of the Republic of Sakha (Yakutia). The populations studied differ from one another with respect to ethnic composition, namely in the ratio between the indigenous and immigrant populations (the indigenous populations are larger in three uluses), in the proportions of representatives of indigenous ethnic groups among men and women contracting marriages, and in the frequencies of monoethnic and interethnic marriages. Positive assortative marriage among persons of the same ethnic group has been demonstrated. The total inbreeding estimated by isonymy (Fit) varies from 0 to 0.007576.     

A study of contemporary levels and temporal trends in inbreeding in the Tangier Island, Virginia, population using pedigree data and isonymy

In this study we describe inbreeding in a large pedigree from Tangier Island, Virginia, in which we compare two commonly used methods to estimate inbreeding in humans: pedigree and isonymy (identical surnames of spouses). Genealogical data on 3,512 individuals dating back to 1722 were used. Using the pedigree method, we determined an average inbreeding coefficient (F) of 0.00873 for the community as a whole, and 0.018 for inbred individuals. Analysis of temporal trends showed that inbreeding began around 1800 and peaked at 0.0109 in 1824-1849 and 1875-1899. Thereafter, inbreeding steadily declined to 0.00565 in 1975-1997. Analysis of pedigree structure complexity over time showed that close consanguinity contributes to inbreeding in the earlier cohorts, and remote consanguinity accounts for much of the inbreeding in the later cohorts. The number of common ancestors increases over time, as does the number of paths connecting inbred individuals to these common ancestors. Inbreeding estimates based on the isonymy approach yielded a 2.2-fold higher value of F (0.01945) compared to the pedigree method. Total isonymy estimates over 25-year cohorts overestimated inbreeding values from pedigree data between 1. 5-8-fold. We speculate that the overestimation is probably due to the inability of our data to satisfy the method's assumption of monophyletic origin of each surname. In conclusion, inbreeding in the Tangier Island population is consistent with the isolated nature of its population, and temporal trends reflect patterns in emigration and a breakdown in isolation over time.     

Population relationships by isonymy in frontier Pennsylvania.

Data from the 1800 US census were used to study relationships by isonymy among 7 civil subdivisions of Bedford County, Pennsylvania. Two analyses of the data were conducted. In the first analysis heads of household served as the unit of analysis. In the second analysis the total number of individuals in each household was used to correct for varying family sizes. All measures of internal differentiation were approximately doubled when the complete population numbers were used. The head-of-household analysis produced FST and RST values of 0.0012 and 0.0007, respectively; the complete population analysis yielded 0.0021 for FST and 0.0015 for RST. Interpopulation a priori kinship estimations were similar using both methods. Conditional kinship estimations varied more, with almost all values negative, but the head-of-household estimates were less negative. Multidimensional scaling of isonymy values coincided fairly well with actual geographic relationships, but a Mantel test revealed no significant relationship between geographic distances and isonymy, and isolation by distance values indicated a low relationship between the 2 measures. The population of the county was heterogeneous, with low kinship between its constituent communities. This appears to be a result of kin-structured long-distance migration rather than of local processes. The head-of-household values are more comparable with other studies and more representative of population relationships; complete population values exaggerate heterogeneity because of random fluctuations in household size.     

Temporal and spatial trends in allozyme frequencies in house fly populations,Musca domestica L.

Summary Allelic and genotypic frequencies were sampled from a single age class of the common house fly, Musca domestica L., at five farms on six dates from July 6 to October 12, 1982. Allozymes at six loci were resolved with vertical polyacrylamide gel electrophoresis. No consistent departures from random mating were detected. No consistent linkage disequilibrium was observed. Allele frequencies at the farms changed in independent and unpredictable ways. Gene frequencies at the five farms were initially divergent, converged in midsummer, and then progressively diverged. The divergence occured in mid-August when fly populations were large. Variation in gene frequencies at adjacent farms accounted for a large proportion of the variance in allele frequencies among all farms. These observations are consistent with the hypothesis that allele frequencies in young adult flies reflected the habitat in which they matured as larvae.Journal Paper No. 11718 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa, Project No. 2411     

Temporal changes in the phytoplankton community structure in a tropical and eutrophic reservoir (Barra Bonita, S.P.--Brazil)

A study of the temporal changes in the phytoplankton communitystructure in the eutrophic Barra Bonita Reservoir (SãoPaulo State, Brazil) was carried out during 30 days (sampleswere taken daily for 10 days and, thereafter, on every otherday) in two distinct seasonal periods (dry and rainy seasons).Monthly sampling occurred in the period July 1993 to June 1994.One hundred and thirty-one taxa were registered. A greater diversity(112 taxa) was observed in winter than in summer (79 taxa).In the monthly analysis, 90 taxa were identified. The highestvalues for species diversity and richness were observed in July1993 and the lowest in April 1994. The phytoplankton dynamicsin this system are apparently dominated by competitive exclusionand disturbance. Within theseasonal cycle, the phytoplanktoncommunity structure was determined by underwater light availability,mixing by wind, precipitation and the consequent loss of Cyanophyceaebiomass in the upper waters by spillage, and nutrient (principallyphosphorus) inputs from anthropogenic sources. The environmentalvariability in this polymictic system may be favouring a phytoplanktoncommunity in equilibrium, with dominance alterations of Bacillariophyceaebiomass (Aulacoseira granulata), R-strategists, and Cyanophyceaebiomass (Microcystis aeruginosa), S-strategists. Short periods(i.e. 10 days) in non-equilibrium conditions with increasedspecies diversity and coexistence can perhaps be explained bythe intermediate disturbance hypothesis.     

Genetic structure of the Saguenay, 1852-1911: evidence from migration and isonymy matrices

The Saguenay is a region in northeastern Québec populated in the second half of the 19th century through migration from other parts of Québec. The present-day population of nearly 300,000 is the result of both immigration and high rates of intrinsic growth. This population has been of interest to geneticists because of the high incidence of certain hereditary diseases, notably spastic ataxia, tyrosinemia, agenesis of the corpus callosum, vitamin D-dependent rickets, and myotonic dystrophy. Parent-offspring migration and isonymy matrices were used to estimate random kinship using the Malécot model for six 10-year time periods from 1852-1911. Comparisons between two estimates of kinship--one from parent-offspring migration matrices (phi) and the other from isonymy (R)--and geographic distance were made using both product-moment and Mantel correlation. Comparisons of within- and between-subdivision kinship were made using nonparametric and Mantel correlation. Within-subdivision kinship from the phi matrix was also compared with kinship estimated from marriage dispensations for endogamous marriages. The estimates of random kinship from the parent-offspring matrices showed a good fit with geography. However, isonymy did not correlate well with geographic distance; and phi and R showed no correlation until the last two time periods, and the diagonal of phi did not correlate with the marriage dispensations. Examination of scatterplots of phi vs. R suggests that nonrandom migration during the process of settlement formation is responsible for the lack of correlation. While movement across space seems to be highly dependent on distance, nonrandom selection of migrants means that between-subdivision estimates of kinship based on migration are not congruent with those obtained by other methods. On the whole, genetic differentiation seems to have been low due to the high levels of movement between subdivisions and immigration. The weak dependence of genetic structure on geographic distances in the present population is demonstrated by mapping the geographic distribution of cases of three recessively inherited diseases.     

Postcranial robusticity in Homo. I: Temporal trends and mechanical interpretation

Temporal trends in postcranial robusticity within the genus Homo are explored by comparing cross-sectional diaphyseal and articular properties of the femur, and to a more limited extent, the humerus, in samples of Recent and earlier Homo. Using both theoretical mechanical models and empirical observations within Recent humans, scaling relationships between structural properties and bone length are developed. The influence of body shape on these relationships is considered. These scaling factors are then used to standardize structural properties for comparisons with pre-Recent Homo (Homo sp. and H. erectus, archaic H. sapiens, and early modern H. sapiens). Results of the comparisons lead to the following conclusions: 1) There has been a consistent, exponentially increasing decline in diaphyseal robusticity within Homo that has continued from the early Pleistocene through living humans. Early modern H. sapiens are closer in shaft robusticity to archaic H. sapiens than they are to Recent humans. The increase in diaphyseal robusticity in earlier Homo is a result of both medullary contraction and periosteal expansion relative to Recent humans. 2) There has been no similar temporal decline in articular robusticity within Homo–relative femoral head size is similar in all groups and time periods. Thus, articular to shaft proportions are different in pre-Recent and Recent Homo. 3) These findings are most consistent with a mechanical explanation (declining mechanical loading of the postcranium), that acted primarily through developmental rather than genetic means. The environmental (behavioral) factors that brought about the decline in postcranial robusticity in Homo are ultimately linked to increases in brain size and cultural-technological advances, although changes in robusticity lag behind changes in cognitive capabilities. © 1993 Wiley-Liss, Inc.     

Marriage trends in the Italo-Greeks of Italy

The Italo-Greek ethnolinguistic minority, living in thirteen villages of southern Italy, marry largely amongst themselves but there are some intermarriages with native Italians. The majority of marriages are within the villages, but there is some marriage movement from one Italo-Greek village to another. Data on marriage and birthplace of parents and grandparents obtained by questionnaires to families of primary school children (aged 6-13 years) are analysed, to show the trends in breakdown of isolation over the last two generations.     

The hierarchical genetic structure of an urban town, Kidlington, Oxfordshire, examined by the coefficient of relationship by isonymy.

The surnames of the 3443 males registered to vote in Kidlington in 1977 yield a Coefficient of Relationship by Isonymy of 0.000564 {Ri = sigma(n(n-1))/2 N(N-1), in which n = the number of men of each surname and N = sigma n}. Those of the four wards separately average 0.000722. However, if one includes only one male of any one surname in each residence, the values are, respectively, 0.000534 and 0.000535. That is, the only structure seen between the two levels is in the influence of men of the same surname resident in the same house. An analysis of relationship by residence on the same street yields a value of Ri somewhat higher than that for the ward as a whole, however, suggesting that even within a ward there may be a tendency for the house of relatives occasionally to lie close together.     

Inbreeding,isonymy, and kin-structured migration in the principality of Andorra

Andorra, one of the smallest countries in Europe, is geographically very isolated. Located in the Central Pyrenees, it is surrounded by high mountains. This paper investigates the endogamous levels and relationships between demographic or geographical variation and inbreeding coefficients calculated through isonymic methods. Our results suggest that political and geographical frontiers are not significant enough to pose effective genetic barriers. The overall inbreeding coefficient average (0.0031) is moderate with respect to other populations in the same region. Temporal and geographical variations of total inbreeding and their components are explained in relation to changes in population size and intensity, and to origin and destination of migrant collectives. Although the spatial distribution of the population of Andorra is the main contributing factor to inbreeding, the kin-structured composition of immigrant collectives is another fundamental factor that helps to explain the levels and variation of inbreeding.