coefficient of inbreeding
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2019 ◽  
Vol 52 (6) ◽  
pp. 809-831
Author(s):  
Juan F. Gamella

AbstractUsing data from the family and genealogical reconstitutions of the Gitano population of 22 contiguous localities in eastern Andalusia, Spain, this study analysed the intensity, structure and historical evolution of consanguinity in 3056 couples formed from 1925 to 2006. Of these unions, 54.8% were consanguineous, and 28.7% involved relatives up to and including second cousins, resulting in a mean coefficient of inbreeding up to the third degree α3 = 12.4 × 10−3. The rest of the consanguineous unions (26.1% of all) involved more-distant relatives, such as third cousins, fourth cousins and so forth. When all consanguinity degrees found in the genealogical reconstitution were considered, the total mean coefficient of inbreeding was αt = 14.8 × 10−3. The merging of families and pedigrees generated a complex genealogical network with many inbreeding loops and important founder effects. This network revealed a high rate (62%) of Multiple Consanguineous Marriages (MCMs) in which second and subsequent consanguineous ties increased inbreeding levels by a fifth (20.5%). The accumulation of multiple degrees of distant relatedness, many of which had little social or biological importance, has contributed to a significant increase in inbreeding rates. Among Gitano people, intra-family marriages have remained common in the last decades, in sharp contrast to other Spanish populations. Hence the highest rates of close consanguinity (34%) and inbreeding (α3 = 14.6 × 10−3) were found in the 1960s, the decade that saw the onset of Spain’s socioeconomic modernization, internationalization and massive migration. These are among the highest rates of inbreeding found in any European population, including the most endogamous Spanish isolates. They reveal marriage strategies not constrained primarily by geographical barriers, but by ethnocultural separation. Interestingly, in recent decades mixed marriages have been increasing rapidly in this minority, although they are compatible with high rates of consanguinity. Gitano secular endogamy is breaking up, but not uniformly.


2019 ◽  
Vol 11 (16) ◽  
pp. 68
Author(s):  
Jackson da Silva ◽  
Andréia Rodrigues Ramos ◽  
Deoclecio Jardim Amorim ◽  
Maurício Dutra Zanotto ◽  
Maria Márcia Pereira Sartori

Oil of castor bean despite its wide range of use, still present a relevant deficit in the Brazilian market. This deficit could be softened or extinguished with increased productivity, in which the genetic aspect has a great contribution. The most productive genotypes are the hybrid varieties, however for obtaining the hybrids pure lineages are required which have appropriate agronomic characteristics and that express the minimum of inbreeding depression. Thus, the objective of this research was to evaluate the inbreeding depression of castor bean progenies, from the cultivar FCA-PB, resulting from three types of pollination. The experiments were implanted in design in randomized blocks, in the 30 × 3 factorial scheme, being 30 progenies and 3 types of pollination (free, cross and self-pollination), in 2 environments (São Manuel and Araçatuba) and in 2 crops (2004/2005 and 2005/2006), with three replications. Inbreeding depression was estimated under the grain productivity variable. It was observed that cross-pollination presented grain productivity close to 2500 kg ha-1, in which the lowest coefficient of inbreeding was determined, zero (0). Opposed It self-pollination, in which resulted in lower productivity, around 2000 kg ha-1, and the highest inbreeding coefficient being of 0.77. The reflection of the coefficient of inbreeding on productivity presents inversely proportional behavior, ie, the measure that increases the coefficient of inbreeding decreases the grain yield.


2018 ◽  
Vol 14 (25) ◽  
pp. 63
Author(s):  
Mohamed Hajjaji ◽  
Abd Errazzak Khadmaoui ◽  
Abd El-Majid Soulaymani ◽  
Younes Azzouzi

The purpose of this work is to contribute to the description of marital practices in Northern Morocco, to follow the evolution of these practices, and to determine the motives for marriages between relatives. Thus our results show a highly significant positive correlation between the age of the two spouses (r = 0.619, p <0.001), with the mean age of the mothers being 49.03 ± 6.56 years, while for the fathers it is 56,02 ± 6,16 years with a difference of 7 years between the two spouses in the current generation. For consanguineous marriages, we identified 51 relatives, namely a frequency of 25.4% for the generation of studied couples GCE, 13.3% for the generation of paternal grandparents GGPP, and 17.5% for the generation of maternal grandparents GGPM. The intergenerational comparison reveals a highly significant increase in the percentage of consanguinity, ranging from the generation of grandparents (15.4%) to that of the studied couples (25.4%), with a difference of 10% (p˂0.001). These results also show that there is a strong association between the prevalence of consanguineous marriages and the group of women under 19 years old (p = 0.002), whereas for husbands it is noted that There is no association between marital status and age at marriage. The coefficient of consanguinity estimated by isonymy is almost twice as large as the coefficient of inbreeding estimated by genealogy.


Author(s):  
Weiwei Ni ◽  
An Jiang ◽  
Jian Zhang ◽  
Guangxin E ◽  
Yongfu Huang

Cattle are the main source of meat in Chongqing. This study investigated the genetic diversity of cattle native to Chongqing and 4 introduced breeds. A total of 96 individuals from 5 breeds were genotyped using six microsatellite markers. Five markers were highly polymorphic within the breed populations, and one marker had moderate levels of polymorphism. Heterozygosity ranged from 0.5379±0.0434 in Simmental to 0.6667±0.0559 in Charolais. The heterozygosity deficit was significant in all populations analyzed compared with the expected level of heterozygosity. In addition, two microsatellite markers (TGLA53 and OarFCB20) deviated from Hardy-Weinberg equilibrium across populations (except in cattle native to Chongqing). The mean number of alleles ranged from 6.00±2.37 in Angus to 7.17±2.14 in Droughtmaster across six markers. The coefficient of inbreeding ranged from 0.0017 in Simmental and Droughtmaster to 0.0367 in Angus. Pairwise difference analyses revealed that Simmental and Droughtmaster were the most differentiated (FST= 0.06861) from each other, whereas cattle native to Chongqing and Charolais were the least differentiated (FST= 0.00557). In summary, this study showed that cattle native to Chongqing and 4 introduced breeds were genetically well protected in Chongqing, and information from this study would be helpful for guiding hybridization and genetic improvements in the future.


Author(s):  
С. Л. Войтенко

У статті висвітлена проблема інбридингу у свинарстві, зокрема під час розведення свиней нечисленної, локальної породи.  Встановлений позитивний вплив  інбридингу на живу масу свинок у процесі їх вирощування. Найбільш високу живу масу за відлучення у 45-денному віці мали свинки із найменшим коефіцієнтом інбридингу (0,78–1,56 %), але в процесі росту тварин, особливо із 6-місячного віку, тенденція змінюється і найбільшу живу масу мали свинки із більш високим коефіцієнтом інбридингу (6,24–11,7 %). Позитивні наслідки інбридингу помірних і віддалених ступенів відмічені і за показниками власної продуктивності свинок. Доведено, що із підвищенням коефіцієнту інбридингу з 1,56 %  до 11,7 % вік досягнення тваринами живої маси 100 кг зменшувався на 11,4 днів (P > 0,95), а товщина шпику, виміряна прижиттєво, – на 2,7 мм. На підставі чого зроблений узагальнюючий висновок про можливість  спорідненого підбору батьківських пар у миргородській породі свиней з метою одержання потомків, комплексний коефіцієнт інбридингу яких не вище 11,7 %. The article deals with the problem of inbreeding in pig breeding, in particular when breeding pigs not numerous, local breed. A positive effect of inbreeding on the live weight of pigs during their cultivation has been established. The highest live weight with weaning at the age of 45 days had mumps with the lowest coefficient of inbreeding (0,78–1,56 %), but in the process of animal growth, especially from the age of 6 months, the trend is changing and the largest live weight was of mumps with a higher coefficient of inbreeding (6,24–11,7 %). The positive influence of inbreeding of moderate and distant degrees is also noted in terms of the own productivity of the pigs. It was proved that with the increase in the coefficient of inbreeding from 1,56 % to 11,7 %, the age of reaching a live weight of 100 kg decreased by 11,4 days (P>0,95), and the thickness of the bacon, measured in vivo, by 2,7 mm. On the basis of which a general conclusion is drawn on the possibility of a related selection of parental pairs in Myrhorod breed of pigs for the purpose of obtaining descendants, the complex inbreeding coefficient of which is not higher than 11,7 %.


2017 ◽  
Vol 50 (4) ◽  
pp. 451-456 ◽  
Author(s):  
Mostafa Saadat ◽  
Mahdis Zarghami

SummarySeveral studies have indicated that consanguineous marriages (unions between biologically related persons) are associated with increased risk of autosomal recessive diseases and several multifactorial traits. Mandaeans are a closed ethno-religious community living in areas of southern Iraq and Iran (Khuzestan Province). There are currently no data on the prevalence of consanguineous marriages among Mandaeans. The present study was carried out in 2016 to determine the prevalence of consanguinity among Iranian Mandaeans living in Khuzestan Province, south-west Iran. A total of 137 couples (urban areas: 79 couples; rural areas: 58 couples) were included in the study. Information on the consanguineous marriages of the subjects was collected through direct interviews. Marriages were classified by the degree of relationship between couples as double first cousins, first cousins, first cousin once removed, second cousins and unrelated marriages. The coefficient of inbreeding (F) was calculated for each couple and the mean coefficient of inbreeding (α) estimated for the population, stratified by rural and urban areas. The overall frequency of consanguinity was found to be 50.7% in urban and 86.2% in rural areas. There was a significant difference between rural and urban areas in types of marriages (χ2=24.8, df=4, p<0.001) and first cousin marriages (51.8%) were the most common type. The overall α-value was estimated to be 0.0363 for the Iranian Mandaean population.


2016 ◽  
Vol 72 (8) ◽  
pp. 491-493
Author(s):  
Elżbieta Czykier ◽  
Jerzy Dackiewicz ◽  
Michał Krzysiak ◽  
Mateusz Cholewski ◽  
Wanda Olech

The aim of this study was to find whether the coefficient of inbreeding is correlated with the incidence of cryptorchidism in the Białowieża line of bison. Our study included 605 male European bison Bison bonasus (L.) born between 1971 and 2015 in the Białowieża Forest. The animals were free-ranging as well as from captive breeding programs. Among the animals culled, there were 144 European bison calves. The calves were not considered in the research, because the descending of the testes in European bison may not occur until a year after birth. The study period, from 1966 to 2015, was divided into 5 decades. The number of male European bison born in each decade was recorded, as well as the number of cryptorchidism cases identified through necropsy in these animals. The percentage of incidence of cryptorchidism among them was calculated for every decade. Subsequently, the Pearson correlation coefficient was calculated between the number of cryptorchidism cases and the coefficient of inbreeding. In 461 male European bison older than 1 year, there were 18 cases of cryptorchidism. In the animals born in the first decade, two autopsical cases of cryptorchidism (0.045%) were recorded, and 4 cases of cryptorchidism (0.03%) were found in the animals from the second decade. Among the bison born in the third decade, there were no cases of cryptorchidism. In the fourth decade, 7 cases of cryptorchidism (0.071%) were diagnosed, and among the bison born during the fifth decade, there were 5 cases (0.111%). The Pearson correlation coefficient suggests that, as the value of the coefficient of inbreeding rises, there is an increase in cryptorchidism cases in male European bison.


2013 ◽  
Vol 46 (5) ◽  
pp. 698-701 ◽  
Author(s):  
AFTAB ALAM STHANADAR ◽  
ALAN H. BITTLES ◽  
MUHAMMAD ZAHID

SummaryInformation on the current prevalence and types of consanguineous marriages in Malakand District, Khyber Pakhtunkhwa Province (KPK), Pakistan, was collected from 1192 rural couples. Some 66.4% of marriages were between couples related as second cousins or closer (F≥0.0156), equivalent to a mean coefficient of inbreeding (α) of 0.0338. The data suggest that the prevalence of consanguineous unions in Malakand has been increasing during the last decade, in response to the high levels of violence across KPK.


2012 ◽  
Vol 45 (6) ◽  
pp. 799-805 ◽  
Author(s):  
MOSTAFA SAADAT ◽  
KHADIJEH TAJBAKHSH

SummaryThe prevalence of consanguinity in eight provinces of Afghanistan has recently been reported by Saify & Saadat (2012). The present cross-sectional study was done in order to illustrate the prevalence and types of consanguineous marriages among other populations of Afghanistan. Data on types of marriages were collected using a simple questionnaire. The total number of couples in this study was 5200 from the following provinces: Farah, Ghazni, Herat, Hilmand, Kabul, Kandahar, Logar, Parwan and Wardak. 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 α in the country was 0.0226, ranging from 0.0203 in Farah province to 0.0246 in Herat province. There were significant differences between provinces for frequencies of different types of marriages (p<0.001). First cousin marriages (21.7%) were the most common type of consanguineous marriages, followed by second cousins (16.0%), first cousins once removed (14.0%), beyond second cousins (6.9%) and double first cousins (1.6%). There was significant difference between ethnic groups for the types of marriages (p<0.001). Tajiks (Soni) and Sadats showed the lowest (α=0.0215) and highest (α=0.0242) levels of consanguinity among ethnic groups in Afghanistan, respectively. The present study shows that the Afghani populations, the same as other Islamic populations, have high levels of consanguinity.


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