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PubMed1984

Inbreeding effect on morbidity: III. A review of the world literature.

A review of the international literature on the inbreeding effect on morbidity is presented. For anomalies in general, the estimates of B vary from 0.2 to 5.8, of A from 0.01 to 0.23, and of B/A from 3 to 77. The respective modal estimates are roughly around 0.5, 0.03, and 20. A review of the estimates for specific anomalies also shows a wide range of values; from B = 0.0008, A = 68 X 10(-8), and B/A = 1,176 (for acheiropodia) to B = 2.9, A = 0.24, and B/A = 12 (for "incapacity for military service"). Some estimates of B/A lower than 12 have been obtained for congenital malformations in some countries. An overall analysis of the whole body of data suggests that most of the anomalies are either entirely or predominantly mutational in origin.

Brazil↗
PubMed1992

Inbreeding effect on morbidity: IV. Further data in Brazilian populations.

The analysis of the data on 5677 children of 1063 couples from a fourth sample of consanguineous and nonconsanguineous marriages among whites and nonwhites living in the State of Minas Gerais, Brazil led to the following estimates: B (number of abnormal equivalents per gamete) around 0.5; A (morbidity in the non-inbred subsamples) 2-3 percent; B/A 13, 15, and 27 (this suggests that the morbidity disclosed by inbreeding may predominantly represent a mutational load); RR (relative risk) about 2 (this means that among the children of consanguineous marriages there is about double the frequency of abnormalities than in those with nonconsanguineous marriages); AR (attributable risk) for the whole sample about 7% (5% for nonwhites and 15% for whites). These last values show the amount that the frequency of abnormalities would decrease in the population if the risk factor (consanguineous marriages) would be eliminated. AR is higher in whites because the frequency of the risk factor is higher among whites.

Brazil↗
PubMed1998

Inbreeding and divorce in blue and great tits.

In blue tits, Parus caeruleus, and other wild birds, matings between close relatives or between genetically similar individuals are associated with fitness costs, often in terms of lower hatching success of the eggs. If individuals cannot assess their genetic similarity to potential mates, those fitness costs may be hard to avoid; however, they may use the proportion of unhatched eggs in their clutch as a cue for their mate choice in the next season. We tested this hypothesis using data from a long-term population study on blue and great tits, Parus major. Divorce in response to inbreeding depression can be considered a special case of the 'incompatibility hypothesis'. As predicted from this hypothesis, both male and female blue tits benefited from divorce when part of their clutch failed to hatch. There was no evidence however, that divorce in blue or great tits was related to the presence of unhatched eggs in the nest. Copyright 1998 The Association for the Study of Animal Behaviour

Journal Article↗
PubMed1977

Inbreeding in recessive diseases.

The consanguinity of parents (born in France) of individuals who have a recessive disease has been studied. The frequency of first cousin marriages is less than 0.2% in the general French population. Among the parents of affected individuals the following frequencies of first cousin matings were observed: cystic fibrosis: 1.4% cystinosis: 7.1% nephronophtisis: 5.6% spinal muscular atrophy: 4.5% albinism: 5.0% achromatopsia: 12.5% (Albinism and spinal muscular atrophy are heterogeneous conditions). The increase in the frequency of first cousin marriage relative to that of the general population is much greater, as expected, in cystinosis, which is a rare disease, than in cystic fibrosis, which is the most frequent recessive disorder in France. Inbreeding in cystinosis and cystic fibrosis was also studied by computing the distance between parental birth places. This distance is smaller in cystinosis than in cystic fibrosis.

Albinism↗
PubMed1993

Inbreeding depression and intelligence quotient among north Indian children.

This study presents the assessment of inbreeding depression on the intelligence quotient among north Indian Muslim Children of school age. The Wechsler Intelligence Scale for Children (WISC-R)-74 was given to the children in both groups (50 each non-inbred and inbred of the first-cousin status), aged 6 to 11 years and from the same socio-economic status. The change of the mean follows genetic theory; however, the nature of the change in variance seems to be somewhat different.

Child↗
PubMed1995

The effects of inbreeding on DNA profile frequency estimates using PCR-based loci.

Estimates of inbreeding were determined using Wright's FST for loci used for PCR-based forensic analyses. The populations analyzed were African Americans, Caucasians, Hispanics, and Orientals. In most cases the FST values at each locus were less than 0.01. The FST values over all loci for African Americans, Caucasians, and Orientals ranged from 0.0015 to 0.0048. No substantial differences were observed for DNA profile frequency estimates when calculated under the assumption of independence or with the incorporation of FST.

Consanguinity↗
PubMed2002

Inbreeding and true seed in tetrasomic potato. IV. Synthetic cultivars.

A true potato seed (TPS) synthetic cultivar from open pollination may broaden the genetic base in potato. A synthetic cultivar can also reduce the effect of inbreeding and maintain the productivity from generation to generation. Selected tetraploid parental genotypes, based on combining-ability tests, were chosen for isolated polycrosses to obtain tetraploid offspring. A series of experiments were undertaken to investigate the development of these TPS synthetic populations in two Peruvian locations: San Ramon, a rainfed, humid, mid-altitude environment, and La Molina, an arid, coastal environment under irrigation. Natural open-pollinated synthetics or control-mixture synthetics, involving two to six parents, had a similar tuber set but plant survival and tuber weight were higher in control synthetics including two or six parents. The results suggest that two-parent open-pollinated TPS synthetics may be a feasible option by selecting the right parents for the base population. A subsequent experiment showed that four-parent control synthetics (i.e. double crosses) were the best for tuber weight and size, followed by the two-parent control synthetics. Synthetic breeding populations could be shared with other breeders, who in cooperation with their local farmers may select promising genotypes for further cultivar release.

Journal Article↗
PubMed1978

Inbreeding effects in a coastal village and other parts of Andhra Pradesh.

A survey was carried out among fisher-women in Pallepalam, in Nellore District of Andhra Pradesh, to determine the prevalence and pattern of consanguinity and its effects on fertility, mortality, and morbidity. Of the 106 marriages investigated, 54.72% were consanguineous with predominant proportions of first cousin (36.79%) and uncle-niece (13.21%) marriages. The average inbreeding coefficients for autosomal and sex-linked genes were found to be 0.0405 and 0.0448 respectively. The differences between consanguineous and nonconsanguineous marriages were studied with respect to fertility, mortality and morbidity.

Child↗
PubMed2000

Equivalence by descent: pedigree analysis with inbreeding and gametic phase disequilibrium.

In the presence of gametic phase disequilibrium and inbreeding, multiple locus genotype frequencies cannot be written solely in terms of identity by descent (IBD) probabilities. Following Cockerham & Weir (1973) we introduce the concept of 'equivalence by descent' (EBD), an extension of the concept of IBD to include non-allelic genes. Two genes are said to be EBD if they derive ultimately from the same founding gamete of a pedigree. Allelic genes that are EBD are also IBD. For two loci 11 EBD probabilities, the 'J-coefficients,' are required and for three loci 117 J-coefficients are required to write genotype probabilities. It is shown how the 117 J-coefficients for three loci can be reduced to a basic set of 37. Computer programs, written in the algebraic programming language, MAPLE, are described which are capable of calculating the two- and three-locus J-coefficients for any pedigree, subject only to size limitations. The MAPLE packages are available from the author upon request.

Chromosome Mapping↗
PubMed1989

Consanguinity in the Archbishopric of Toledo, Spain, 1900-79. I. Types of consanguineous mating in relation to premarital migration and its effects on inbreeding levels.

This study, the first of a series on consanguinity in the Archbishopric of Toledo from 1900 to 1979, analyses in detail the types of consanguineous mating in a population of considerable size, some 650,000 persons, in Central Spain. During the period covered, very important transformations occurred in Spanish society. The data relate to 21,464 consanguineous marriages. They were divided into two groups, according to the premarital migration of the couple. Significant differences in the frequencies of the types of consanguineous matings, and their secular evolution, are found for the two groups. The expected trend in inbreeding in the total area shows two different tendencies: constancy till the end of the 1950s, followed by a fast decline during the last two decades.

Catholicism↗
PubMed2003

Multiple new phenotypic taxa from trees and riparian ecosystems in Phytophthora gonapodyides-P. megasperma ITS Clade 6, which tend to be high-temperature tolerant and either inbreeding or sterile.

Phytophthora isolates associated with Phytophthora major ITS Clade 6 were grouped into 11 phenotypic taxa. These comprised the described morphospecies P. gonapodyides, P. megasperma s. str. and P. humicola; four previously identified but so far undescribed taxa, informally designated here P. sp. O-group, P. sp. Apple-cherry, P. taxon Pgchlamydo, and P. taxon Walnut; and four previously unknown taxa, designated P. taxon Oaksoil, P. taxon Raspberry, P. taxon Forestsoil, and P. taxon Riversoil. With the exception of P. gonapodyides, each phenotypic taxon represented an unique ITS lineage. Two isolates morphologically identical to P. gonapodyides comprised a separate lineage and probably represent another taxon, designated here P. taxon Salixsoil, P. humicola, P. sp. O-group, P. sp. Apple-cherry and P. taxon Walnut grouped together as subclade I. Within subclade II, P. taxon Oaksoil, P. taxon Raspberry, P. taxon Forestsoil, P. taxon Riversoil and P. taxon Pgchlamydo formed a cluster of closely related but phenotypically distinct lineages basal to P. gonapodyides and P. megasperma, P. taxon Salixsoil being the most basal member. The taxonomy, adaptation and breeding systems of Clade 6 taxa are discussed. They show a strong association with forests and riparian ecosystems, only a limited association with agriculture and an ability to tolerate high temperatures. Also, in contrast to most other Phytophthora clades, Clade 6 taxa are predominantly sterile or inbreeding in culture. Only one taxon, P. sp. O-group, appears classically A1/A2 heterothallic.

DNA Restriction Enzymes↗
PubMed1979

Endogenous mammary tumour virus DNA varies among wild mice and segregates during inbreeding.

Proviruses of the mouse mammary tumour virus (MMTV) endogenous to normal mice can be identified by molecular hybridisation and distinguished using restriction endonucleases. Feral mice display marked heterogeneity with respect to the number of copies and the sites of insertion of endogenous MMTV-specific DNA, with occasional mice apparently free of MMTV DNA. Several different MMTV proviruses present in laboratory mice have segregated like stable, independent genetic elements during the inbreeding which followed a cross between Bagg albino and DBA mice 60 years ago. The results favour the hypothesis that endogenous proviruses have been established by multiple, independent infections of germ cells rather than by somatic mutation of ancestral proviruses or of cellular genes.

Animals↗
PubMed2003

Fluctuating asymmetry in a secondary sexual trait: no associations with individual fitness, environmental stress or inbreeding, and no heritability.

It has been suggested that fluctuating asymmetry (FA) in secondary sexual traits may be a useful indicator of either individual quality or environmental stress. We tested this concept using a series of analyses of FA in male antler size in a wild red deer (Cervus elaphus) population, using four measures of size repeated across successive years on the same individuals. We found no consistent evidence of correlations between traits in levels of FA, nor of any associations between known environmental or developmental conditions. None of the four measures of FA showed a significant heritability (average h2 = 0.041), nor was there any evidence of inbreeding depression. For three of the four traits, fluctuating asymmetry did not predict either annual or lifetime breeding success. However there were significant associations between breeding success and FA in antler length. Given the series of null results in our other tests, it seems likely that this was a direct mechanistic effect rather than because measures of FA were indicative of individual quality or condition.

Animals↗
PubMed1977

Inbreeding, marital movement, and genetic isolation of a rural Appalachian population.

Genealogical, marital, birthplace and age-at-marriage data were collected on a random sample of 275 reproducing couples from the population of a rural Appalachian county in north-eastern Tennessee. Genealogies covering the three extant generations provided the data for a surname isonymy analysis to determine the amount of inbreeding prevalent, while the marital, birthplace and age at marriage data were used to ascertain the components of marital movement, i.e., marital distance, orientation of marital movement, spatial exogamy, and "diffusion". The effective breeding population and effective immigration rate were calculated for the county population and these in turn were used to compute the coefficient of breeding isolation for the currently reproduction population. Our conclusions agree with those of an earlier genetic and demographic study on one segment of the same population. The more extensive demographic analysis illustrates the value of such studies as this for providing background for interpretations of genetic variation.

Consanguinity↗
PubMedDate not supplied

Genetic composition of Jewish populations: diversity and inbreeding.

Genetic diversity and F statistics analysis, using 9 and 5 blood group loci, respectively, were carried out on 16 Jewish populations from 5 geographic regions: East Europe, Central Europe, South Europe, Middle East and North Africa. The proportion of total diversity found within populations was 98.9% while that between populations, within geographic groups and between groups altogether was only 1.1%. The average heterozygosity between geographic groups ranged from 0.3867 to 0.4150. There were no significant differences between geographic groups of populations in heterozygosity or in its variance. Average estimates of inbreeding were as follows: Fis = 0.0419, Fst = 0.0084 and Fit = 0.0498. Because the heterogeneity and relative proportion of diversity were less between Jewish populations than between non-Jewish ones, we conclude that genetic similarity between Jews is higher than between Gentiles. The findings are in agreement with our previously obtained calculations of genetic distances (Kobyliansky, Micle, Goldschmidt-Nathan, Arensburg and Nathan 1982).

Africa, Northern↗
PubMedDate not supplied

Inbreeding coefficients from isonymy in the Italian-Greek villages.

There are four Italian-Greek communes in one area of Calabria and nine in an area of Apulia. The communes are too small to give good information on marital isonymy for each, but in the Calabrian area the weighted mean inbreeding coefficient and its random and non-random components are F = 0.01442, Fr = 0.00450 and Fn = 0.00997, respectively. The weighted means in the more populous Apulian area are significantly lower, F = 0.00423, Fr = 0.00379, Fn = 0.00045.

Consanguinity↗