Medicogenetic study of isolates in Uzbekistan. I. Statement of the problem and characteristics of the groups studied]

The paper comprises results of studying some demographic and populaton characteristics of the inhabitans of the Samarkand region as a whole and two villages, Karakent and Ishan, inhabited with Uzbeks-Khoja, a special religious-social caste in the past. It is shown that 87.4% of marriages in the Samarkand region are of international character (the information has been obtained on 7995 married couples). The frequency of consanguineous marriages is 11.6%, and among them 40.5% are first-cousin marriages and 39.1% are marriages of remote relatives. The coefficients of inbreeding are rather high among the Jewish, Tajik and Uzbek communities. The coefficient of inbreeding as a whole is F=0.0042 in this region and approaches to the maximal level, characterizing a panmix population. The average size of a family in the villages of Karakent and Ishan is approximately 4.0 persons. The values of reproductive performance, the nature of termination of pregnancies do not differ from those of panmix population. The percentage of intravillage and consanguineous marriages are 56% and 12.5% for the first village, and 25% and 2% for the second one respectively. The coefficient of inbreeding for karakent is F=0.0064, for Ishan--F=0.0014. Taking into consideration the historical development of the two villages and the cumulative data, the conclusion is drawn that Karakent is an isolate on a religious ground whereas Ishan is a disintegrated isolate.     

Genetic demographic description of the Ust-Aldan rural population of Sakha Republic (Yakutia): migrations and marriage structure

Migrations, dynamics of the gametic structure of rural populations, and marriage structure with respect to birthplaces and inbreeding estimated from isonymy have been studied in the Ust-Aldan ulus (administrative district) of Sakha Republic (Yakutia). The villages studied (Byadi, Dyupsya, and Cheriktey) are characterized by intense migration; however, the migration radius is small (most migrations occur within the district). The rural populations studied differ in the intensities and directions of gamete flows and their dynamics. There is no substantial gamete flow into the Ust-Aldan population from outside Sakha Republic. About 50% of marriages contracted in this population are homolocal (between residents of the same district); the endogamy is low (15%). In most cases of heterolocal marriages (contracted between residents of different districts), one of the spouses is a local resident. The inbreeding estimated from isonymy is FTT = 0.002930 in Yakuts; it is mainly accounted for by the nonrandom component (FIS = 0.002232 and FST = 0.000700).     

Genetic Demographic Description of the Ust-Aldan Rural Population of Sakha Republic (Yakutia): Migrations and Marriage Structure

Migrations, dynamics of the gametic structure of rural populations, and marriage structure with respect to birthplaces and inbreeding estimated from isonymy have been studied in the Ust-Aldan ulus (administrative district) of Sakha Republic (Yakutia). The villages studied (Byadi, Dyupsya, and Cheriktey) are characterized by intense migration; however, the migration radius is small (most migrations occur within the district). The rural populations studied differ in the intensities and directions of gamete flows and their dynamics. There is no substantial gamete flow into the Ust-Aldan population from outside Sakha Republic. About 50% of marriages contracted in this population are homolocal (between residents of the same district); the endogamy is low (15%). In most cases of heterolocal marriages (contracted between residents of different districts), one of the spouses is a local resident. The inbreeding estimated from isonymy is F _IT = 0.002930 in Yakuts; it is mainly accounted for by the nonrandom component (F _IS = 0.002232 and F _ST = 0.000700).     

Trends in inbreeding, isonymy, and repeated pairs of surnames in the Valserine Valley, French Jura, 1763-1972

The estimates of inbreeding derived from pedigrees and frequency of isonymous marriages (i.e., between persons of the same surname) are compared using genealogical and isonymic information from 4,899 marriages recorded between 1763 and 1972 in 4 rural villages of the French Jura region (a mountainous area near the Swiss border). Before the second half of the 20th century, the two kinds of estimates show a different temporal evolution. The mean inbreeding coefficient based on pedigrees increases between 1763 and 1852 and reaches a maximum between 1853 and 1882 (alpha = 0.0028), with a very low percentage (< 1%) the result of remote kinship. The mean inbreeding coefficient based on isonymy is always higher, with a maximum observed between 1793 and 1822 (F = 0.0200), and it remains roughly the same between 1763 and 1882 (F = 0.0150), with a high percentage resulting from a random component (Fr), a consequence of the small population size and genetic drift. After 1883, the 2 mean coefficients decrease. This discordance is largely explained by the poor quality, for the first periods, of the genealogical data base, which ignores the more remote links of kinship, justifying the use of the model of Crow and Mange (1965) to explore consanguinity during the more ancient periods. The temporal evolution of the repeated pairs of surnames index (RP) confirms the recent evolution of the marital structure of the valley. Moreover, it appears that isonymous marriages and repeated and unique pairs of surnames constitute 3 distinct matrimonial groups characterized by both a different mean coefficient of inbreeding (alpha) and a different rate of endogamy.     

Evolution of marital structure in 20 Sardinian villages from 1800 to 1974

This paper reports the data for endogamy, exogamy and consanguinity in 20 Sardinian villages from 1800 to 1974, divided into generational periods (25 years). The data are taken from the records of 48,262 marriages celebrated in the parishes of 20 Sardinian villages. The results for Spearman's rank correlation coefficient indicate significant positive correlations of endogamy with consanguinity (r(s) = 0.6551, percentage of consanguineous marriages; r(s) = 0.5477, Bernstein's alpha), with altitude (r(s) = 0.6386), with population size (r(s) = 0.2519), as well as a significant negative correlation of endogamy with time (r(s) = -0.4210). In addition, consanguinity shows a significant positive correlation with altitude (r(s) = 0.5717, percentage of consanguineous marriages; r(s) = 0.6295, Bernstein's alpha) and a significant negative correlation with time (r(s) = -0.2363, percentage of consanguineous marriages); the negative correlation between the mean level of consanguinity (alpha) and time is statistically not significant. In the single parishes, the levels of endogamy and consanguinity are generally higher in the mountain villages than in those situated in the hill and plain areas. Finally, it is hypothesized that, in the time period considered, the level of consanguinity and especially of endogamy were largely determined by isolation.     

Genetic demographic characteristics of the rural population of the Tuva Republic: marriage structure and inbreeding]

Marriage structure was studied in three rural populations of the Tuva Republic: the Shinaan population and the populations of Todzhinskii and Bai-Taiginskii raions (districts). The Shinaan and Bai-Taiginskii populations had high levels of endogamy (0.6704 and 0.6050, respectively). In the Todzhinskii population, which was characterized by a mixed ethnic composition, endogamy was 0.3779 for the total population and 0.4626 for Tuvinians; interethnic marriages in this population were rare. The values of marriage assortativeness with respect to birthplace were 19.38, 40.75, 75.87, and 41.87% in the Shinaan, Bai-Taiginskii, all the Todzhinskii populations, and Tuvinian monoethnic marriages in the Todzhinskii raion, respectively. High marriage assortativeness with respect to ethnicity was found. Its values (A') were 91.85 and 93.49% in Tuvinians and Russians, respectively. Tuvinian populations were characterized by high inbreeding. The total (F(it)), random (Fst), and nonrandom inbreeding (Fis) estimated by isonymy were 0.004237, 0.002298, and 0.001944 in the Shinaan population, 0.007292, 0.009448, and -0.002177 in the Bai-Taiginskii population, and 0.003846, 0.004152, and -0.000307 in the Todzhinskii population, respectively (in the latter populations, the F(it), Fst, and Fis values for Tuvinian marriages alone were 0.005000, 0.007222, and -0.002238, respectively). The results obtained indicate that individual territorial groups of Tuvinians retain a high degree of genetic isolation from one another.     

Genetic and demographic characteristics of rural populations of Altaĭ republic: dynamics of the marriage structure

The dynamics of population marriage structure in the period from 1951 to 1997 has been studied in three villages of Altai Republic: Kulada (Ongudaisk raion), Beshpeltir (Chemal raion), and Kurmach-Baigol (Turochak raion). These populations have been found to differ from one another in the intensity and direction of migration, as well a its temporal pattern with respect to the birthplaces and ethnicity of persons contracting marriages. Periods of active incorporation of non-Altaian (mostly Slavic) ethnic components into the gene pools of the Beshpeltir and Kurmach-Baigol populations have been detected. The geographic distributions of the birthplaces of men and women contracting marriages are different. Therefore, migration has different effects on the genetic diversity of the Y-chromosomal and mitochondrial-DNA pools. No isonymic marriages have been found in the Altaian populations studied; however, an increase in the random component of inbreeding has been observed.     

Medical-genetic study of the population of the Lenkoran district of the Azerbaijani Republic

As a result of the genetic analysis of the population among the children’s population up to 14 years old of the Lenkoran district of the Azerbaijani Republic it was discovered that the phenotypic frequency of hereditary diseases and congenital malformation make up 0.274% according to the MLEC data and 5.12% according to self-made research. The high level of multifactorial and autosomo-recessive hereditary types indicates the high frequency of occurrence of marriages of genetic relatives in the district under study.     

Trends of consanguineous marriages in a Sunni Muslim population of West Bengal, India

The Muslim population of the Chaltaberia village in the district of South 24 Parganas in West Bengal is divided into several wards (paras) inhabited by people of specific surnames. The frequency of endogamous marriages within surnames is greater than randomly expected ones. An incomplete reproductive isolation is observed among the five dominant surnames. Consanguineous marriages occur more often outside the village than inside. Leaving out marriages between long distances, a small median distance of 6.36 km is recorded. The neighborhood area works up to be 552.2 km2, which is rather small. There is an underlying process of breeding isolation by distance. A generation length of 21 years has been used for examining the temporal change in consanguineous marriages and inbreeding, which generally appears to increase. There is a general trend of decline in consanguineous marriages towards the southern part of West Bengal and eastern part of Assam among the Bengalee Muslims. The frequency of consanguineous marriages is 7.3% out of all marriages (N=1153) that have taken place in six generations in the population. The first cousin marriage is nearly 50% of all marriages. Patrilineal marriages are common in marriages between second and third cousins. An increase of consanguineous marriages in the younger generation was observed, but the total frequency agrees with a general trend of a decline in the frequency of consanguineous marriages among the Muslims in this part of India.     

Inbreeding and nephrolithiasis in Croatian island isolates

The aim of this study was to investigate a recessive genetic component in susceptibility to nephrolithiasis (NL) by comparing its prevalence in highly inbred, moderately inbred and non-inbred villages of three Croatian islands: Brac, Hvar and Korcula. The average inbreeding coefficient of each village population (F) was estimated in a random sample of 20-30% adults from 14 villages using Wright's path method (based on genealogical information), isonymy data and average deviation from Hardy-Weinberg expectations for MN, Ss and Kk serogenetic polymorphisms. The six villages with the greatest genealogical F value (0.025-0.049; current total population N=1,401), the four with intermediate value (0.012-0.015; N=998) and the four with the smallest value (0.002-0.008; N=1,500) were chosen for this study. Medical records of entire populations were reviewed and the diagnosis of NL was established according to unified criteria, based on the information from the specialists in general hospitals and on the agreement in diagnosis between the investigators and local general practitioners. The variance in environmental and socio-cultural factors between villages was shown to be minimal. Prevalence of NL in each village was standardised by sex and age to the total population of all 14 villages. The standardized prevalence of NL was 1.5% in the group of villages with low F, 2.3% in the group with moderate F (p<0.10), and 5.4% in the group with high F (p<0.001). The correlation factor between F values by villages and the standardized prevalence of NL was 0.45 (p<0.05). The study showed that a large number of predominantly recessive genetic factors might mediate the susceptibility to formation of renal stones in humans.     

Isolation and marriage patterns in four South Tyrolean villages (Italy) during the nineteenth century

No information is currently available on the marriage patterns of German-speaking communities of the South Tyrol area. The aim of this study is to investigate the reproductive isolation of four South Tyrolean mountain villages during the 19th century. Data about 3953 marriages were drawn from existing pedigrees and completed with data from the parish registers of the studied villages to calculate the following indicators: age at marriage, endogamy, inbreeding from dispensations and from isonymy and repeated pairs of surnames among couples. The results show high levels of endogamy (78-87%) and an elevated age at marriage in all the studied villages. The percentages of consanguineous marriages (10-33%) vary considerably but result overall in relatively low inbreeding values (alpha 0.0015-0.0036; Ft 0.0098-0.0138). Levels of endogamy are consistent with the geographic characteristics of the area, while inbreeding values are lower than those observed in previous studies on Alpine communities. This is due to a low frequency of marriages between close relatives, probably related to the peculiar demographic and cultural characteristics of the studied populations that differentiate them from neighbouring Italian-speaking villages.     

Genetic and demographic characteristics of rural populations of Altai Republic: The marriage structure dynamics

The dynamics of population marriage structure in the period from 1951 to 1997 has been studied in three villages of Altai Republic: Kulada (Ongudaisk raion), Beshpeltir (Chemal raion), and Kurmach-Baigol (Turochak raion). These populations have been found to differ from one another in the intensity and direction of migration, as well a its temporal pattern with respect to the birthplaces and ethnicity of persons contracting marriages. Periods of active incorporation of non-Altaian (mostly Slavic) ethnic components into the gene pools of the Beshpeltir and Kurmach-Baigol populations have been detected. The geographic distributions of the birthplaces of men and women contracting marriages are different. Therefore, migration has different effects on the genetic diversity of the Y-chromosomal and mitochondrial-DNA pools. No isonymic marriages have been found in the Altaian populations studied; however, an increase in the random component of inbreeding has been observed.Translated from Genetika, Vol. 41, No. 2, 2005, pp. 261–268.Original Russian Text Copyright © 2005 by Kucher, Tadinova, Puzyrev.     

Consanguineous marriages in Afghanistan

The present cross-sectional study was done in order to illustrate the prevalence and types of consanguineous marriages among Afghanistan populations. Data on types of marriages were collected using a simple questionnaire. The total number of couples in the study was 7140 from the following provinces: Badakhshan, Baghlan, Balkh, Bamyan, Kabul, Kunduz, Samangan and Takhar. Consanguineous marriages were classified by the degree of relationship between couples: double first cousins, first cousins, first cousins once removed, second cousins and beyond second cousins. The coefficient of inbreeding (F) was calculated for each couple and the mean coefficient of inbreeding (α) estimated for each population. The proportion of consanguineous marriages in the country was 46.2%, ranging from 38.2% in Kabul province to 51.2% in Bamyan province. The equivalent mean inbreeding coefficient (α) was 0.0277, and ranged from 0.0221 to 0.0293 in these two regions. There were significant differences between provinces for frequencies of different types of marriages (p<0.001). First cousin marriages (27.8%) were the most common type of consanguineous marriages, followed by double first cousin (6.9%), second cousin (5.8%), beyond second cousin (3.9%) and first cousin once removed (1.8%). There were significant differences between ethnic groups for the types of marriages (χ2=177.6, df=25, p<0.001). Tajiks (Soni) and Turkmens (also Pashtuns) showed the lowest (α=0.0250) and highest (α=0.0297) mean inbreeding coefficients, respectively, among the ethnic groups in Afghanistan. The study shows that Afghanistan's populations, like other Islamic populations, have a high level of consanguinity.     

Genotypes of vitamin-D-binding protein (DBP) in patients with chronic obstructive pulmonary disease and healthy population of Republic Bashkortostan

The distribution of alleles and genotypes of vitamin D-binding protein (DBP) gene has been studied in patients with Chronic Obstructive Pulmonary Disease (COPD, n = 298) and healthy individuals (n = 237) from two ethnic groups (Tatars and Russians) living in Republic Bashkortostan. Statistically significant differences in the distribution of DBP gene genotypes between Tatars and Russians (chi2 = 8.854, df = 5, P = 0.04) were revealed. The pattern of allele's distribution within DBP gene was similar in healthy control subjects of both ethnic groups, with gradient reduction in row GC*1S> GC*1F> GC*2. The most common genotypes were: GC*1F/1S in Tatars (36.79%) and GC*1S/2 in Russians (34.62%). It has been shown, that Tatars with genotype GC*1F/1S have a lower risk of COPD development: the frequency of GC*1F/1S genotype in COPD patients was significantly lower than in healthy individuals (19.85% versus 36.79%; chi2 = 7.622, P = 0.0067, Pcor = 0.0335; OR = 0.42 CI 95% 0.22-0.79). At the same time, COPD patients from the same group had higher frequency of GC* 1F/2 genotype than healthy individuals (19.08% versus 8.49%; chi2 = 4.52, P = 0.033, Pcor = 0.165; OR = 2.54 CI 95% 1.067-6.20). In Russian population the distribution of alleles and genotypes of DBP gene were similar in COPD patients and healthy individuals.     

Endogamy among the Dogon of Boni, Mali

This paper examines factors influencing endogamy in a Dogon population in Mali. Situated in Boni district, this population of about 5000 individuals is distributed over fifteen villages located on four independent massifs. This population is strongly endogamous (only 4% of all marriages are contracted with neighbouring ethnic groups), and each massif shows high endogamy. The roles of lineage, residence in the same village, and geographical distance in mating choice are examined. These different factors are successively analysed using log-linear statistical models and the results offer a more precise interpretation of endogamy in this population.     

Inbreeding among endogamous groups in three multicaste villages of Srikakulam district,Andhra Pradesh,India

Abstract

In the present paper 702 families have been studied belonging to different endogamous groups in three multicaste villages of Srikakulam District, Andhra Pradesh. It is observed that 33.76 per cent of families are consanguineous marriages. With regard to the types of marriages, 12.11 per cent are uncle‐niece; 14.10 per cent are matrilateral cross‐cousins; 5.84 per cent are patrilateral cross‐cousins; 0.57 per cent are first cousins once removed, and 1.14 per cent are second cousins. There are only six couples (0.86 per cent) in intercaste marriages. The coefficient of inbreeding for autosomal and sex‐linked genes, 0.045 and 0.059, respectively, for Chakalis which are higher than Kalingas (F = 0.03; F1 = 0.038), Segidis (F = 0.031; F1 = 0.041), Velamas (F = 0.026; F1 = 0.036), Vysyas (F = 0.027; F1 = 0.034), Malas (F = 0.017; F1 = 0.026), and others (F = 0.026; F1 = 0.032). The t‐tests for mean marriage distances are statistically significant among all castes, but chi‐squares for intergroup difference of consanguineous and nonconsanguineous marriages are statistically significant only among Kalingas and Chakalis, Vysyas and Chakalis, and Malas and Chakalis.     

Consanguineous marriages in the province of Antalya, Turkey

To assess the trends in the frequency and the medical effects of consanguinity in the south coast of Turkish population using local and national data in the last 11 years. This cross-sectional study was carried out in Manavgat province, which is a major tourism center on the Mediterranean coast of Turkey. The authors studied consanguineous marriages in rural and urban population in the Mediterranean coast, Manavgat province, Turkey, via a 1500 random survey sample of married couples. There has been a significant increase in the incidence of consanguineous marriages in rural areas (40.7%) since 1989 in the southern population of Turkey. The results showed that the most frequent type of marriage was between the first cousins. It is found that there is no statistically significant difference between the consanguineous and non-consanguineous marriages in the different age groups. The results were discussed on the basis of educational status, reasons for having consanguineous marriages and the general medical effects as well as with the relation of congenital malformations. The custom of consanguineous unions in the Mediterranean population of Turkey is still extremely high, and preventive measures should be done to decrease its frequency and associated complications.     

Population demographic structure of the city of Ulan Ude: Ethnic composition and age at marriage

The marriage structure of the population of Ulan Ude, the capital of Buryat Republic, which is characterized by a mixed ethnic composition, has been studied. Differences between Ulan Ude districts in a number of genetic demographic parameters have been found. In ethnic terms, the city district populations differ from one another in the number of ethnic groups and the proportions of the largest groups (Russians and Buryats). In the total Ulan Ude population, the proportions of Russian men and women among persons contracting marriages are 71.44 and 73.79%, respectively; those of Buryat men and women are 23.36 and 22.79%, respectively. The total proportion of all other ethnic groups among both men and women contracting marriages is no more than 5.2%. The mean ages at first marriage in both indigenous and immigrant populations of Ulan Ude are relatively old; these values are 25.9 and 24.72 years for Buryat men and women and 24.86 and 22.69 for non-indigenous men and women, respectively.     

Consanguineous marriage in the capital city Sana'a, Yemen

Consanguineous marriage is traditionally common throughout the Eastern Mediterranean region, especially in the mainly Muslim countries. To date, there is little information on consanguinity in Yemen. The aim of this study was to ascertain the rate of consanguineous marriage and average coefficient of inbreeding in Sana'a City, Yemen. A population survey was conducted with the intention of covering married couples resident in Sana'a City by means of a multi-stage random sampling technique. A total of 1050 wives and husbands were interviewed on consanguinity in their households. The total incidence of consanguinity was 44-7% (95% CI 41.7-47.7%) with first-cousin marriages constituting 71.6% of the total consanguineous marriages and 32% of all marriages. Paternal parallel first cousins (Type I) accounted for 49% of first-cousin marriages. The average coefficient of inbreeding (F) was 0.02442. The incidence of consanguinity is relatively high in Yemen with predominantly first-cousin marriage. This might be related to the deeply rooted social and cultural beliefs in the country.     

Inbreeding and learning disability in Croatian island isolates

The aim of this study was to investigate the prevalence of learning disability (LD) in isolate populations with different inbreeding coefficients (F). Prevalence of LD and F were determined in 10 villages from five Croatian islands: Brac, Hvar, Korcula, Lastovo and Susak. For the purpose of this study, LD was defined as the inability to attend the public school system. As the elementary schools (grade 1-8) in the place of the study are both public and compulsory, the assessment of child's inability to attend the school is performed at the age of six. This is required by all children in the country based on standard set of tests of cognitive performance defined by the Ministry of Education and Culture of the Republic of Croatia. The average inbreeding coefficients in each village population (F) were estimated in a random sample of 20-30% adults in each of the 10 villages based on 4 ancestral generations and using Wright's path method. Prevalence of LD ranged from 0.43% to 2.47%, and the inbreeding coefficients ranged from 0.8% to 4.9%. The Pearson's correlation coefficient between F and LD prevalence was 0.80 (p < 0.01). Although the relative risk per 5% inbreeding appeared very high (about 10), the absolute risk only increased from 0.18% to 1.77%. The genetic effect of inbreeding (GEI) was approximately 0.69% and the population-attributable fraction 76.6%. A review of the literature and the results of this study lead to a conclusion that a very large number of predominantly recessive genetic factors might mediate the genetic susceptibility to various forms of LD in these populations.