Local differences in the Archbishopric of Santiago de Compostela (Galicia, Spain) in relation to the consanguinity structure, 1900-1979

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, Berganti?os, 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.     

Inbreeding levels and consanguinity structure in the Basque province of Guipúzcoa (1862-1980)

This work analyzes the spatial heterogeneity of consanguinity in the Basque province of Guipúzcoa (Spain), using data provided by Catholic dispensations (1862-1980). Secular trends in consanguinity rates (%M(C)) and mean inbreeding coefficient (F) were similar in the seven Guipúzcoan regions considered, with peaks between 1881-1920 and subsequently a gradual decline. Substantial differences in consanguinity characteristics emerged when the regions were classified according to level of urbanization. Principal component analysis (accounting for more than 85% of the total variance in consanguinity variables) clearly discriminated between urbanized and less urbanized regions. The latter stand out for their high consanguinity rates (3.57-6.73%), mean inbreeding coefficient (0.00112-0.00240), and M22/M33 ratio (M22, first cousins; M33, second cousins), which ranged between 0.89-1.48. Moreover, in less urbanized regions, marital consanguinity was eminently local, and mainly conditioned by regional endogamy (71.4-85.0%). By contrast, urban subpopulations showed the lowest consanguinity rates (1.60-1.96%) and mean inbreeding coefficient (around 0.0007). In these regions, the M22/M33 ratio also exhibited high values (1.07-1.56), but this time at the expense of the contribution of the immigrant group. Discussion of the factors that could have modeled this spatial variation in consanguinity centers on: 1) demographic aspects related to the chronology and intensity of industrialization, 2) the geography of the territory and the geography of peopling, and 3) linguistic differences, expressed in the uneven distribution of Basque-speakers among the different territories considered.     

Human papillomavirus in invasive cervical cancer and cervical intraepithelial neoplasia 2 and 3 in Venezuela: A cross-sectional study

BackgroundThis study investigated the distribution of human papillomavirus (HPV) types in invasive cervical cancer (ICC), cervical intraepithelial neoplasia 2 (CIN2) and cervical intraepithelial neoplasia 3 (CIN3) in Venezuela.MethodsParaffin-embedded samples from 329 women from 29 medical centers of the 24 states of Venezuela were analyzed to determine the distribution of HPV types for ICC, CIN2, and CIN3, the prevalence of single and multiple infection, and the association of HPV types with severity of lesion, comparing CIN2 versus CIN3+ (CIN3 and ICC). The samples were analyzed with the polymerase chain reaction (PCR) followed by reverse hybridization for the identification of HPV types.ResultsHPV was identified in 95/96 ICC specimens (98.9%), in 142/149 CIN3 (95.3%) and in 78/84 CIN2 samples (92.8%). The most common types for ICC and CIN3 were: HPV16, 18, 31, and 33, and for CIN2 were HPV16, 31, 51, 52, and 18. HPV single infection was found in 82.1% of ICC cases, in 79.4% of CIN2 cases, and in 77.4% of CIN3 cases. HPV16 was identified as a single infection more frequently in women with CIN3+ than in those with CIN2 (68.6% versus 46.7%, P = 0.002), and HPV16 or HPV18 types were more prevalent in CIN3+ than in CIN2 (73.4% versus 50%, P = 0.0006).Conclusionthis is the first study of the distribution of HPV types in ICC, CIN2, and CIN3 conducted throughout the territory of Venezuela. HPV16 and HPV18 were the most frequent HPV types identified in single and multiple infections in both ICC and CIN3 groups, and are associated with severity of lesion. The knowledge of the distribution of HPV types would allow organization of an HPV-DNA-based screening test, and consideration of the implementation of prophylactic vaccination in Venezuela.     

Age correlation between mates and average consanguinity in age-structured human populations

When population geneticists wish to determine the genetic consequences of some aspect of mating behavior, it is often necessary to compare observed levels of consanguinity to the level expected when mating is random with respect to the factor being studied. Expectations under random mating are often derived from discrete generation models that ignore age structure. Observed frequencies of consanguineous matings are due to processes that are continuous in time and are affected by variables that are functions of age structure. The extent to which this discrepancy between the models and reality might distort conclusions drawn from comparisons of observed and expected behavior has received insufficient attention. One potential source of error is the tendency for people to choose mates whose ages differ from their own by a certain amount; this tendency influences the frequency of consanguineous matings. Age correlation between mates should therefore also affect average consanguinity between mates and average inbreeding in the population. Expected levels of consanguinity might then differ depending on whether or not age structure has been taken into account. Hajnal developed a model that predicts the frequencies of consanguineous matings in age-structured populations. Hajnal's model is extended here to include relationships that are defined by lineal descent as well as by common ancestry, and to allow calculation of the frequencies of consanguineous matings in the absence of age correlation between mates. The extended model is then used to determine the effect of age correlation between mates on average consanguinity under various sets of conditions. The magnitude of this effect depends on the degree to which the increased frequency of some types of consanguineous matings is offset by the decrease in other types of matings. There is a fairly wide range of conditions under which this compensation is nearly complete and therefore under which the overall effect of age correlation is small. But the size of this effect is sensitive to many factors, especially the distribution of age differences between mates and the variances of ages at maternity and paternity. Under some conditions, age correlation between mates will have a substantial effect on average consanguinity.     

Microsatellite analysis of the spectacled bear (Tremarctos ornatus) across its range distribution

DNA samples of the spectacled bear (Tremarctos ornatus) from five Andean countries, Venezuela, Colombia, Ecuador, Peru and Bolivia, were analyzed for nine microsatellite loci. Seven of them were polymorphic, which led us to investigate several population-genetic parameters. Private alleles and significant differences in gene frequencies were found among the populations studied, which demonstrated the extent of genetic differentiation among the spectacled bear populations. The levels of gene diversity measured with these microsatellites were rather modest in this species. Hardy-Weinberg disequilibrium was especially found for the overall and the Ecuadorian samples, and might be due to the Wahl-und effect or consanguinity. Significant genetic heterogeneity was mainly observed among the Colombian and the Ecuadorian populations. Markov chain Monte Carlo simulations clearly showed that two different gene pools were present, one present in the Venezuelan-Colombian bears and other in the Ecuadorian ones.     

Consanguineous marriage in a newly developed country: the Qatari population

This study examines the frequency of consanguineous marriage and coefficient of inbreeding in the State of Qatar. The study was conducted in semi-urban areas of Doha between January and May 2004. A sample of 1515 married Qatari females aged 15 years and over participated. The degree of consanguinity between each female and her spouse, and degree of consanguinity between their parents were recorded. The rate of consanguinity in the present generation was high (54.0%) with a coefficient of inbreeding of 0.02706. The commonest type of consanguineous marriage was between first cousins (34.8%). Double first cousin marriages were common (3.1%) compared with other populations. The consanguinity rate in the State of Qatar has increased from 41.8% to 54.5% in one generation.     

Interspecific competition between freshwater snails of medical importance: a Venezuelan example

Lake Valencia is located in the centre of the endemic area of the intestinal schistosimiasis in Venezuela. The dominance of two pulmonate species, Biomphalaria glabrata and B. prona., was observed in the lake. Both species are strongly associated with two distinct types of habitats suggesting that competition is occurring between these two species. B. glabrata and B. prona play the role of intermediate hosts of schistosomes in Venezuela. At the present time, parasite transmission is not occurring in the lake but the planning of important development programmes represents a risk of creation of active schistosomiasis foci. The knowledge of the importance and distribution of the snail host populations is therefore essential and must be taken into account for developing future control strategies.     

A Two-Locus Forensic Match Probability for Subdivided Populations

A two-locus match probability is presented that incorporates the effects of within-subpopulation inbreeding (consanguinity) in addition to population subdivision. The usual practice of calculating multi-locus match probabilities as the product of single-locus probabilities assumes independence between loci. There are a number of population genetics phenomena that can violate this assumption: in addition to consanguinity, which increases homozygosity at all loci simultaneously, gametic disequilibrium will introduce dependence into DNA profiles. However, in forensics the latter problem is usually addressed in part by the careful choice of unlinked loci. Hence, as is conventional, we assume gametic equilibrium here, and focus instead on between-locus dependence due to consanguinity. The resulting match probability formulae are an extension of existing methods in the literature, and are shown to be more conservative than these methods in the case of double homozygote matches. For two-locus profiles involving one or more heterozygous genotypes, results are similar to, or smaller than, the existing approaches. This revised version was published online in August 2006 with corrections to the Cover Date.     

Harmonizing regulations for biomedical research: a critical analysis of the US and Venezuelan systems

This article aims to compare the national legal systems that regulate biomedical research in an industrialized country (United States) and a developing country (Venezuela). A new international order is emerging in which Europe, Japan and the United States (US) are revising common guidelines and harmonizing standards. In this article, we analyze - as an example - the US system. This system is controlled by a federal agency structured to regulate research funded by the federal government uniformly, either in the US or abroad. In contrast, in Venezuela, a developing country, the creation of a centralized system is a slow process. Different types of ethical committees review research projects using non-uniform criteria. Consequently, various parallel organizations that conduct biomedical research, such as universities, research institutes and private hospitals have diverse regulations operating at a local level. Thus, the most relevant difference between the Venezuelan and the US systems is the degree of standardization. In the US, the review process is performed by institutional review boards (IRBs), which have a similar organization and maintain relationships with a centralized agency, following standard regulations. Although new proposals for establishing national regulations are currently being considered in Venezuela, the success of these initiatives will depend on promoting governmental efforts to create a more structured centralized system supported by a national regulatory framework. This system will need governmental financial support at all levels. This article proposes an integrated system to regulate research with human participants in Venezuela and other developing countries.     

Estimation of inbreeding by isonymy in Iberoamerican populations: an extension of the method of Crow and Mange

The method of isonymy for the estimation of inbreeding levels was extended to use the potentialities offered by the Iberoamerican surname system, in which a child inherits his surnames both from the father and the mother. Four possible types of isonymy were recognized between the family names of a husband-wife pair. It was found that, limited to simple consanguinity, the ratio between isonymy and the inbreeding coefficient of consanguineous individuals, starting from first cousins, is constant and equal to 16. Consanguinity levels were studied in four Venezuelan groups, Isla de Toas, Los Teques, Quibor, and Colonia Tovar, using genealogies, classical isonymy, and the extended method. It was found that, for Iberoamerican populations, the extended method is more precise than the classical method.     

Consanguinity and prereproductive mortality in the Utah Mormon population

To test the effects of parental consanguinity on mortality among offspring, inbreeding coefficients were estimated for 303,675 members of the Utah Mormon population who were born between 1847 and 1945. Although consanguinity has been relatively rare in this population, the large sample size permitted the identification of more than 3,500 inbred offspring. Among the offspring of unrelated parents, 13.2% died before the age of 16. Significant elevations in prereproductive mortality were seen among the offspring of first-cousin marriages (22%) and among the offspring of closer unions (32%). The cor- responding relative risks are 1.70 (95% confidence limits = 1.52, 1.91) and 2.41 (95% confidence limits = 1.59, 3.41), respectively. Other categories of relationship did not produce significant elevations in offspring mortality. Similar results were obtained when a case-control approach was used to remove the effects of socioeconomic variation. Consistent with many other studies of populations with low consanguinity rates, this population experienced a relatively high absolute increase in mortality among the offspring of first-cousin marriages (9%). Preliminary evidence is offered for the hypothesis that mortality differentials are larger in populations with low inbreeding and low mortality because nongenetic causes of death do not obscure the effects of consanguinity.     

Evolution of consanguinity in a French alpine valley: the Vallouise in the Brianfon region (17th-19th Centuries)

The present study considers the evolution of consanguinity in the Vallouise, a high glacial valley in the French Alps. The genealogical method was used to estimate consanguinity in this Alpine population from the 17th to the 19th centuries. This method was then compared with three other methods used to measure consanguinity. The results indicate that while consanguinity increased through time (marriage dispensations and genealogies), the structural consanguinity (isonymy) was very stable throughout the entire period.     

两个猪苓菌株生长速度及酯酶同工酶比较研究

对不同地理分布的猪苓纯培养菌株进行了种性和酯酶同工酶的比较研究,结果表明,鸡爪苓（Z）纯培养菌株和猪屎苓（ZJ）纯培养菌株的种性有很大不同,两个纯培养菌株的酯酶同工酶酶带类型差异较大,亲缘关系较远。     

Socioeconomic, demographic and legal influences on consanguinity and kinship in northern coastal Sweden 1780-1899

Most studies on consanguinity have been conducted on contemporary populations and have focused on the prevalence and types of preferred intra-familial marriage. With its comprehensive birth, marriage and deaths records dating back to the late 17th century, and the legal bar on first cousin marriage removed in the mid-19th century, Sweden offers unique opportunities to examine the factors that determine by whom, where and why consanguineous marriages were contracted. The present study covers the period 1780-1899 and presents a detailed portrait of cousin and sibling exchange marriages in the Skellefte? region of northern coastal Sweden. The combined prevalence of first, second and third cousin marriage increased from 2.3% in 1790-1810 to 8.8% in 1880-1899, and multi-generation consanguinity also increased significantly over the study period. The distribution and prevalence of first cousin marriages was strikingly non-random, with a significantly greater propensity for consanguinity among land-owning families, especially involving first-born sons, within specific pedigrees, and in a number of more remote inland communities. Additional factors associated with a greater likelihood of consanguineous marriage included physical or mental disability among males, and among females the prior birth of an illegitimate child. Besides the inherent interest in the social and demographic structure of this region of northern Sweden during the course of the 19th century, in future studies it will be important to determine the degree to which the observed patterns of consanguineous and sibling exchange marriages in these past generations could have influenced present-day genetic structure.     

Consanguinity trends and correlates in the Palestinian Territories

Secondary analysis of the trends and correlates of consanguinity in the Palestinian Territories was conducted using data from two separate surveys in 1995 and 2004. The analysis was conducted on ever-married women aged 15-54 who were asked about their relation to their husband in both surveys. A total of 16,197 women in 1995 and 4971 women in 2004 were successfully interviewed. Consanguinity was found to be widely practised in the Palestinian Territories with rates of total consanguinity reaching 45% of all marriages in 2004. Analysis was conducted with the data from the two surveys combined and this indicated that consanguinity was significantly decreasing with time after controlling for other variables. Age of the women, their age at marriage, region and locality type they lived in and their standard of living were all found to be significant predictors of consanguinity. The education level of the women was not found to be significant. After controlling for the survey year, women's labour force status was also found to be a non-significant predictor of consanguinity. Although consanguinity was found to be significantly decreasing slowly with time after controlling for other variables, the future trends of consanguinity are not known due to the unstable political situation in the territories, which could have a direct effect on marriage patterns.     

Parental consanguinity as a cause for increased incidence of births defects in a study of 238,942 consecutive births.

The risk for birth defects in the offspring of first-cousin matings has been estimated to increase sharply compared to non consanguineous marriages. As a general decline in the frequency of consanguineous marriages was observed in this century, one wonders whether consanguinity is still a factor in the appearance of birth defects in developed countries. Based on our registry of congenital anomalies we tried to answer to this question. In the population studied in North-Eastern France a consanguineous mating was known in 1.21% of the cases with congenital anomalies, vs. 0.27% in controls, (p < 0.001). The frequency of the malformations recorded paralleled the degree of consanguinity: out of 89 malformed children, 51 were seen in first-cousins mating (10.3 times more frequent than in offspring of non consanguineous couples), 17 in second-cousins marriages and 18 in more distant relatives mating. Three were uncle-niece marriage. Excluding known mendelian conditions these numbers were 73, 36, 17 and 17 respectively and the corresponding relative risk were 3.68, 3.01, 3.41 and 4.89 respectively. Therefore there is a negative dose-response effect between level of inbreeding and risk of congenital malformations. Consanguineous mothers were more often pregnant than non consanguineous mothers (p < 0.01) and they had more stillbirths than non consanguineous mothers. These results show that consanguinity is still a factor of birth defects and they must be taken into account for genetic counseling of inbred marriages, in developed countries.     

Army ants in four forests: geographic variation in raid rates and species composition

1. The New World army ants are top predators in the litter of tropical forest, but no comprehensive studies exist on variation in assemblage-wide activity and species composition. We used standardized protocols to estimate foraging raid rates and species composition of army ant communities in four Neotropical forests. The study sites spanned approximately 10 degrees latitude, with two sites each in Central and South America. 2. We recorded a total of 22 species of army ants. The four sites varied in observed and estimated species richness. Species overlap was highest between the Central American sites, and lowest between the South American sites. 3. Raid activity varied significantly among sites. Raid activity per kilometre of trail walks was over four times higher at the most active site (Sta. Maria, Venezuela) than at the least active site (Barro Colorado Island, Panama). Furthermore, each site showed a different diel pattern of activity. For example, raid activity was higher during daylight hours in Costa Rica, and higher at night in Venezuela. Raid activity relationships with ambient temperature also varied significantly among sites. 4. The overall rate of army ant raids passing through 1 m(2) plots was 0.73 raids per day, but varied among sites, from 0 raids per day (Panama) to 1.2 raids per day (Venezuela). 5. Primarily subterranean species were significantly more abundant in Venezuela, and above-ground foragers that form large swarm fronts were least abundant in Panama. The site heterogeneity in species abundance and diel activity patterns has implications for army ant symbionts, including ant-following birds, and for the animals hunted by these top predators.     

Consanguinity in two Spanish regions: La Cabrera and Fuentes Carrionas. Dispensations and isonymy

In this work the level and structure of consanguinity is analysed in two Spanish rural regions of similar geographic and orographic characteristics for the period between 1880 and 1979, employing two different methodologies. The estimates according dispensations shows that the total levels (alpha4 = 0.00552 in La Cabrera and 0.00405 in Fuentes Carrionas) and the structures of consanguinity (C22/C33 = 0.43 and 0.34) are similar in both regions, but have evolved differently. Whereas in La Cabrera both parameters have remained stable, in Fuentes Carrionas they fluctuated through the period analysed. On studying the structure of consanguinity more closely using the isonymic method, it can be seen that in La Cabrera total consanguinity (Ft = 0.0206) should be attributed mainly to environmental factors (Fr = 0.0193) and to a lesser extent to socio-cultural factors (Fn = 0.0013), whereas in Fuentes Carrionas it derives, almost exclusively, from the former (Ft = 0.01270; Fr = 0.01589; Fn = -0.00325).     

Consanguinity and endogamy

This study distinguishes consanguinity, endogamy and social milieu. It reveals three facts: (a) the action of consanguinity is greater on mental capacities than on bodily dimensions; (b) endogmay, when distinguished from consanguinity, has on the contrary a more marked effect on body size than on mental abilities. This effect is additional to that of consanguinity; occasionally it exacerbates it (negative interaction); (c) the social milieu adds its effects to those of consanguinity and it explains the larger part of the endogamic depression.