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PubMed1996

The inheritance of factors associated with joint mobility.

From a sample of 1,500 individuals belonging to 442 migrant nuclear families from northeastern Brazil, information on the interphalangial mobility was obtained: (a) the grades of extension of both the right and left thumbs and (b) the angle (in degrees) formed by the distant and proximal phalanx of the thumb. The first principal component of these variables was estimated and called "extensibility." A negative association of extensibility and age, as well as with inbreeding, was detected. Complex segregation analysis was applied to extensibility and both a multigenic mechanism and an extra transmissible component were detected. Mendelian inheritance was rejected, while a model with multifactorial inheritance, together with a factor that is inherited with a transmission probability different from 1/2 (tau = 0.63), was not rejected. These findings were supported by path analysis, which showed an important biologic inheritance (h2 = 0.675) and the existence of a small but significant cultural component (c2 = 0.003). The observed "inbreeding" effect, therefore, could not be attributed to a genetic mechanism and probably is the effect of concomitant environmental variability.

Brazil↗
PubMed2001

Consanguinity and congenital heart disease in Saudi Arabia.

First-cousin marriage may be a significant risk factor for specific types of congenital heart disease in a consanguineous population. Inbreeding studies suggest an autosomal recessive component in the cause of some congenital heart defects. We studied a large sample of patients with structural congenital heart defects (CHD) identified through the Congenital Heart Disease Registry at King Faisal Specialist Hospital in Riyadh, Saudi Arabia. After exclusions of chromosome abnormalities and non-participation, data were collected on 891 consecutive patients who were registered between January and August, 1998. Data on first-cousin consanguinity and type of CHD diagnosis were collected. A z test of proportions was used to determine the association between consanguinity and subtypes of CHD. Data indicate that the proportion of first cousins in the CHD sample is higher than the proportion in the general population, supporting a hypothesis of autosomal recessive gene involvement in congenital heart disease. When subgroups of CHD were analyzed, first-cousin consanguinity was significantly associated with ventricular septal defect (VSD), atrial septal defect (ASD), atrioventricular septal defect (AVSD), pulmonary stenosis (PS), and pulmonary atresia (PA). There was no relationship between consanguinity and tetralogy of Fallot (TOF), tricuspid atresia (TA), aortic stenosis (AS), co-arctation of the aorta (CoA), and patent ductus arteriosus (PDA). Thus, in a population with a high degree of inbreeding, consanguinity may exacerbate underlying genetic risk factors, particularly in the offspring of first cousins. There may be a recessive component in the causation of some cardiac defects.

Adolescent↗
PubMed2002

Genome-wide scan for linkage to schizophrenia in a Spanish-origin cohort from Costa Rica.

Genetic isolates have been useful cohorts in which to search for genes underlying disorders of unknown pathology. One such cohort is thought to exist in the Central Valley of Costa Rica surrounding the city of San Jose. Previous investigators identified a rare dominant gene for hereditary deafness in this population, and a suggestive linkage of severe bipolar psychosis has been reported in another study. Ninety-nine families with at least one pair of siblings affected with schizophrenia or a schizophrenia-spectrum diagnosis had clinical evaluations and DNA collected for genotyping. The Marshfield Medical Research Foundation (NHLBI) Mammalian Genotyping Service performed all genotyping using 404 short-tandem repeat polymorphic markers (STRPs) spaced on average 10 cM apart. Data were analyzed using the nonparametric program, GeneHunterPlus. The population structure was investigated using the STRUCT program. No region was found with genome-wide significance for linkage. Using a phenotype of schizophrenia plus schizoaffective disorder, the highest maximum likelihood score (MLS) observed was 1.78 (P < 0.004) at 176.6 cM from pter on chromosome 5q, an area previously implicated by some other groups. In addition, five regions on chromosomes 1p, 2p, 2q, 14p, and 8p had MLSs above 1.0. All other regions produced scores below 1.0. Population genetic analysis reveals no evidence for population substructure, for admixture with other populations, such as Amerindians, or for inbreeding in the parental generation. The latter casts some doubt on this population being an isolate, although there was evidence of inbreeding among the offspring.

Chromosome Mapping↗
PubMed1978

Alkaptonuria in the Trencín District of Czechoslovakia.

For several years the Clinical Genetics Research Laboratory at Martin, Czechoslovakia, has been studying alkaptonuria (AU) in the northern part of the District of Trencín in Slovakia. These affected individuals are part of a group of 103 alkaptonurics originated mostly in the mountainous parts of Slovakia. We report results of pedigree analyses; population and affected-family biochemical urine screening; estimation of inbreeding coefficient, of exogamy rate and of average marital distance and of calculation of the frequency of the AU allele, and of homozygotes and heterozygotes in this portion of the Trencín District. Twelve homozygotes were found, but seven originated from a single hamlet in which a founder effect - genetic drift and inbreeding - are thought to account for the high prevalence of AU.

Alkaptonuria↗
PubMed1985

Congenital anomalies in the Hutterite population: a preliminary survey and hypothesis.

The Alberta Provincial Congenital Anomaly (CA) Surveillance reporting forms were scanned for infants whose surnames and addresses identified them as belonging to the Hutterite Brethren. Death registrations (of infants up to 1 year) and stillbirth registrations were similarly scanned. While the overall percentage of total malformations (5%) and major malformations (2%) was no different from that of the total population of Alberta, closer examination of the actual entities showed a large number of monogenic disorders among the Hutterites. The frequency of multifactorial congenital anomalies was approximately 1%. The inbreeding coefficients, using a genealogic data base, were computed for each "case baby" and two Hutterite "control babies," the latter being births preceding and succeeding the case baby. There was no statistical difference in the distribution of inbreeding coefficients between the case and control groups. While the data are based on small numbers and therefore are preliminary, they suggest that the Hutterite lifestyle, of good nutrition (using largely home prepared foods), absence of tobacco and minimal alcohol consumption, may be one factor responsible for fewer multifactorial CAs whose occurrence is environmentally susceptible to such influences. Studies of populations with a low incidence of disorders are just as important as those with a high incidence.

Alberta↗
PubMed2001

Sources of variability in numbers of live births in wild golden lion tamarins (Leontopithecus rosalia).

We examined the effects of several variables on the number of live births in multiparous females in a wild population of golden lion tamarins (Leontopithecus rosalia). Independent variables included the number of infants born to a female the previous breeding season, the number of infants weaned the previous breeding season, the female's age and body mass, the number of adult males and helpers in the group, and the inbreeding coefficient of the offspring. We also tested the hypothesis that trapping and chemical immobilization during pregnancy affected the number of live births. Female body mass was the only statistically significant predictor of the number of live-born infants in the current season when both first and second peaks were included. Characteristics that predicted higher numbers of infants in the first peak of a season were the number of infants born the previous season and the body mass of the female. The greater the number of infants born the previous season, the greater the number of infants born in the first peak of the current season. Factors positively correlated with the number of live births in the second peak within a season included the number of infants born the previous season, as well as the number of available helpers. Due to sample size constraints, the analysis of litters in the second peak did not include body mass of the female as a variable. Inbreeding and handling did not affect the number of live births. We found no evidence that current reproduction negatively impacts future reproduction in this species. We also found no evidence for an age-related reduction in fertility.

Age Factors↗
PubMed2005

Color-vision polymorphism in wild capuchins (Cebus capucinus) and spider monkeys (Ateles geoffroyi) in Costa Rica.

New World monkeys are unique in exhibiting a color-vision polymorphism due to an allelic variation of the red-green visual pigment gene. This makes these monkeys excellent subjects for studying the adaptive evolution of the visual system from both molecular and ecological viewpoints. However, the allele frequencies of the pigments within a natural population have not been well investigated. As a first step toward understanding the relationship between vision and behavior, we conducted color-vision typing by analyzing fecal DNA from two wild groups of white-faced capuchin monkeys (Cebus capucinus) and one group of black-handed spider monkeys (Ateles geoffroyi) inhabiting Santa Rosa National Park of Costa Rica. All color-typed monkeys were individually identified. In C. capucinus and A. geoffroyi we found three and two pigment types, respectively, and the spectral mechanism that created one of the two Ateles pigments was found to be novel. In one Cebus group and the Ateles group, all alleles were present, whereas in the other Cebus group only two alleles were found, with one allele predominating. This was likely due to the effect of close inbreeding, indicating that wild populations can exhibit a variety of allele compositions. This result also suggests that the color-vision polymorphism can be easily distorted by natural factors, such as inbreeding, skewing the population structure.

Animals↗
PubMed1977

On the meaning of increased fluctuating dental asymmetry: a cross populational study.

Suarez reports a greater magnitude of fluctuating dental asymmetry for Neandertal sample when compared with a sample of modern Ohio whites. He postulates that this greater antimeric variance could be due to a greater degree of inbreeding in the Neandertal populations. In the present investigation, the magnitude of fluctuating dental asymmetry is evaluated for Eskimo and Pueblo populations. These populations were found to exhibit dental variance of equal magnitude to that of the Neandertal population. As these populations are not highly inbred, a stress related mechanism is suggested to explain these observations and the inbreeding hypothesis is rejected. The implications of this mechanism to Brace's Probable Mutation Effect are discussed.

Bicuspid↗
PubMed1986

Gene flow and variation in stature and craniofacial dimensions among indigenous populations of southern Mexico, Guatemala, and Honduras.

Populations with histories of outbreeding tend to be taller even in the face of seemingly unchanged health and nutritional circumstances, while inbreeding generally results in a negative correlation between body dimensions and level of inbreeding. Populations that have experienced a positive secular trend in stature and maturation typically have histories of higher outbreeding rates in combination with improved nutritional, health, and economic conditions, suggesting a genetic-environment interaction. In general, Middle American Indians have not experienced a secular trend in stature, nor a substantial increase in their standard of living, but they have experienced varying degrees of admixture with Spanish and African populations since the Spanish Conquest. The relationship between estimated gene flow and variation in several anthropometric dimensions is thus considered in indigenous Mesoamerican populations. Available data on height, sitting height, craniofacial dimensions, and admixture rate of Indian populations from southern Mexico, Guatemala, and Honduras were assembled from the literature. The population mean data on 3,371 adults from 23 populations for males and 18 for females were analyzed by regression with anthropometry as the dependent variable, and log10 of admixture as the independent variable. Admixture was less than or equal to 28.9% in this study and is suggestive of a primarily traditional Indian cultural and economic base. The results suggest that populations with higher admixture tend to be taller, and that the increase in stature is due to greater subischial length in both sexes. A decrease in nasion-menton height, and an increase in nasal breadth, nasal height, and the nasal index is suggested for the dimensions of the craniofacial complex.(ABSTRACT TRUNCATED AT 250 WORDS)

Anthropometry↗
PubMed1982

Correlates of ovarian morphology, estrous behavior, and cyclicity in an inbred strain of miniature swine.

Ovarian morphology and behavioral relationships were studied in a group of nine miniature pigs with a characteristically small litter size (-5) and an average coefficient of inbreeding of 0.39. The first day of standing estrus was designed as day 0, Laparoscopy was used to evaluate and photograph ovarian activity on days 1, 5, 11, 17, and day 2 of the subsequent estrous cycle. Mean (+/-SEM) duration of estrus and the estrous cycle was 3.1 +/- 0.2 and 22.6 +/- 0.3 days, respectively. An average of 9.0 +/- 0.4 vesicular follicles developed/estrous period and 96% of the follicles showed morphologic evidence of ovulation resulting in a mean of 8.6 +/- 0.3 corpora lutea (CL) per animal. There was no significant correlation between the degree of inbreeding and number of vesicular follicles (r = 0.27) or CL (r = 0.28) developing/cycle within the experimental group. Mature preovulatory follicle and CL size ranged from 6-12 mm and 8-12 mm in diameter, respectively, and 22.5% of the newly formed CL contained distinct postovulatory stigmata. These data indicated that 1) temporal relationships of sexual behavior and gross ovarian morphology in the miniature pig were similar to descriptions previously reported for the standard pig, and 2) the reduced litter sized characteristic to this particular strain is, at least in part, due to decreased number of vesicular follicles developing during the estrous cycle.

Animals↗
PubMed2026

Genetic (Genomic) and Morphological Evidence Suggest That the Korean Endemic Fat Minnow (Rhynchocypris kumgangensis) and the Deogyu Population Represent Distinct Species.

Geographically disconnected populations of freshwater fishes often show ecological and genetic divergence in response to opposing selection differentials in different habitat environments, sometimes leading to the formation of ecotypes and even speciation. Nevertheless, evidence for the speciation through allopatric processes in freshwater fish systems remains scarce. Kumkang fat minnow (Rhynchocypris kumgangensis), a Korean endemic coldwater fish, has recently been suggested to diverge into a separate species (Rhynchocypris deogyuensis). However, the level of their genetic and ecological divergence remains largely unknown. We analyzed population genetic structure of R. kumgangensis together with R. deogyuensis using mitochondrial DNA (mtDNA) and eight newly developed microsatellite markers. Genetic divergence at mitogenome level was further assessed between the presumed two species. Moreover, we examined morphology between two groups by analyzing morphometric traits and also conducted geometric morphometrics on body shape. We found distinct population structure between R. kumgangensis and R. deogyuensis at both mtDNA and microsatellites. One remnant population of R. deogyuensis harbored only a single haplotype and showed a very high level of inbreeding. Comparative analysis of the mitogenomes showed approximately 2.9% divergence between R. kumgangensis and R. deogyuensis, supporting the species-level divergence. The analyses of both morphometric traits and geometric morphometrics indicated significant morphological divergence between the two species. The observed low values of length-weight relationship and condition factor for R. deogyuensis are likely to be attributed to effects of the elevated level of inbreeding and depleted genetic diversity. Overall, our combined genetic/genomic and morphological analyses suggest the considerable divergence between R. kumgangensis and R. deogyuensis, supporting the hypothesis that they are distinct species. The mechanisms underpinning how they speciate still need to be studied further in detail.

Deogyu fat minnow↗
PubMed1999

Female reproductive strategies, paternity and community structure in wild West African chimpanzees.

Although the variability and complexity of chimpanzee behaviour frustrates generalization, it is widely believed that social evolution in this species occurs in the context of the recognizable social group or community. We used a combination of field observations and noninvasive genotyping to study the genetic structure of a habituated community of 55 wild chimpanzees, Pan troglodytes verus, in the Taï Forest, Côte d'Ivoire. Pedigree relationships in that community show that female mate choice strategies are more variable than previously supposed and that the observed social groups are not the exclusive reproductive units. Genetic evidence based on nuclear microsatellite markers and behavioural obser-vations reveal that females in the Taï forest actively seek mating partners outside their social unit; noncommunity males accounted for half the paternities over 5 years. This female mating strategy increases male gene flow between communities despite male philopatry, and negates the predicted higher relatedness among community males. Kin selection seems unlikely to explain the frequent cooperation and sharing observed among group males in this population. Similarly, inbreeding avoidance is probably not the sole cause of permanent adolescent female dispersal as a combination of extragroup mating and avoidance of incest with home group males would allow females to avoid inbreeding without the hazards associated with immigration into a new community. Extragroup mating as part of chimpanzee females' reproductive strategy may allow them to choose from a wider variety and number of males, without losing the resources and support provided by their male social group partners. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1994

Inherited enhancement of hydroxyl radical generation and lipid peroxidation in the S strain rats results in DNA rearrangements, degenerative diseases, and premature aging.

Previously by selection and inbreeding of Wistar rats susceptible or resistant to the cataractogenic effect of galactose the S and R rat strains differing in the intensity of hexose transport into the animal cells were developed. High level of OH-radical generation and enhanced lipid peroxidation are revealed in the liver and myocardium of the S rats in contrast to the R rats. Data are obtained supporting the view that enhanced generation of OH-radicals within the S rat tissues is due to oxidation and autooxidation of the abundant amounts of monosacharides intensely accumulating in the rat cells. In spite of continuous inbreeding for more than 40 generations and a high rate of homozygosity, numerous DNA rearrangements are revealed in the S rat genomes. Fragility of the S rat cell membranes is detected. Cataracts and other lens lesions, emphysema, tumors, cardiomyopathy-like changes in the myocardium, scoliosis, brain disfunctions are characteristic of the S rats, as well as low fertility and short life-span indicative of premature aging.

Aging↗
PubMed2001

Recombinant congenic strains derived from A/J and C57BL/6J: a tool for genetic dissection of complex traits.

Complex genetic traits can be dissected in mice, using well-defined sets of recombinant inbred strains, congenic strains, and recombinant congenic strains (RCS). We report the creation of a series of 37 independent RCS derived from the commonly used inbred strains of laboratory mouse A/J (A) and C57BL/6J (B6). These RCS were derived by systematic inbreeding of independent pairs of animals from a (F1 x A) x A and a (F1 x B) x B double backcross (N3), to create AcB and BcA strains, respectively. Fifteen AcB strains and 22 BcA strains at between 18 and 30 generations of inbreeding have been generated, are healthy, and show stable breeding performance. These strains have been genotyped for a total of 625 informative microsatellite DNA markers covering the entire genome, with an average spacing of 2.6 cM. Haplotype analyses indicate that on average, AcB and BcA strains contain 13.25% of the donor genome, a value close to the 12.5% expected from the breeding scheme used in their creation. In the AcB set, approximately 79% of the B6 genome has been transferred in independent strains, while in the BcA set approximately 84% of the A genome is represented on the B6 background. This represents an excellent coverage of congenic segments from both parental genomes in the two sets of strains, which can now be used to map simple and complex traits in a genome-wide fashion. As an example of the power of AcB/BcA strains as a mapping tool, the 37 strains were typed for susceptibility to infection with Legionella pneumophila, a monogenic trait controlled by the Lgn1 locus on Chromosome 13. Analysis of the strain distribution pattern of L. pneumophila susceptibility allowed direct mapping of Lgn1 to a 3-cM interval. The AcB/BcA set should prove a useful tool with which to investigate the complex genetic basis of known interstrain differences between A and B6 for many important diseases.

Animals↗
PubMed1996

Comparison of ribosomal DNA sites in Lolium species by fluorescence in situ hybridization.

The position of the 18S-5.8S-26S and 5S rRNA genes have been physically mapped on the chromosomes of seven Lolium taxa. 18S-5.8S-26S sites were seen on two pairs of chromosomes in the inbreeding taxa. In the outbreeding taxa six sites were found in the L. multiflorum, seven in L. perenne and nine in L. rigidum var. rigidum. Two 5S sites were found in each of the taxa. In the inbreeders, the 5S sites were found adjacent to the 18S-5.8S-26S sites on chromosome 2. In L. multifiorum and L.perenne the 5S sites were on the short arm of chromosome 3. However, in L. rigidum var. rigidum the 5S rDNA site was found in either of the two positions.

Chromosome Mapping↗
PubMed2002

Old-growth red spruce forests as reservoirs of genetic diversity and reproductive fitness.

Old-growth forests are assumed to be potential reservoirs of genetic diversity for the dominant tree species, yet there is little empirical evidence for this assumption. Our aim was to characterize the relationship of stand traits, such as age, height and stem diameter, with the genetic and reproductive status of old-growth and older second-growth stands of red spruce (Picea rubens Sarg.) in eastern Canada. We found strong relationships between height growth (a fitness trait) and measures of genetic diversity based on allozyme analyses in red spruce. The negative relationship between height and the proportion of rare alleles suggests that high proportions of these rare alleles may be deleterious to growth performance. Latent genetic potential, however, showed a significant and positive relationship with height. Stand age was not correlated to height, but was correlated to seedling progeny height. In late-successional species such as red spruce, age and size (e.g., height and stem diameter) relationships may be strongly influenced by local stand disturbance dynamics that determine availability of light, growing space, moisture and nutrients. In larger and older stands, age appeared to provide a good surrogate measure or indicator for genetic diversity and progeny height growth. However, in smaller and more isolated populations, these age and fitness relationships may be strongly influenced by the effects of inbreeding and genetic drift. Therefore, older populations or old-growth forests may represent superior seed sources, but only if they are also of sufficient size and structure (e.g., stem density and spatial family structure) to avoid the effects of inbreeding and genetic drift. Thus, larger and older forests appear to have an important evolutionary role as reservoirs of both genetic diversity and reproductive fitness. Given the rapid environmental changes anticipated (as a result of climate change, increasing population isolation through fragmentation, or following the introduction of exotic pests and diseases) these older populations of trees may have a valuable function in maintaining the adaptive potential of tree species.

Genetic Variation↗
PubMed2003

Genetic evaluation of alternative silvicultural systems in coastal montane forests: western hemlock and amabilis fir.

Genetic diversity and mating system were quantified for shelterwood, patch cut and green tree-retention silvicultural systems, and compared to adjacent old-growth. This is a component of a larger study conducted in montane old-growth forests of coastal British Columbia to evaluate the feasibility and ecological consequences of alternative silvicultural systems. The experiment includes replicated treatments representing a range of overstory removal adjacent to old-growth and clearcut areas. Based on 22 electrophoretically assayed loci, the effects of silvicultural systems on genetic parameters of amabilis fir (Abies amabilis and western hemlock (Tsuga heterophylla were assessed by comparing an average number of alleles per locus, the percent polymorphic loci, and observed and expected heterozygosity between parental populations and naturally regenerated progeny as well as among treatments. Genetic variation in natural regeneration was greater than in parental populations, especially for low-frequency alleles. Silvicultural treatments caused no significant differences in amabilis fir genetic-diversity parameters, while the shelterwood system resulted in lower observed and expected heterozygosity in western hemlock. Nei's genetic distance revealed that all parental populations were extremely similar. The two species had contrasting mating system dynamics with amabilis fir producing higher levels of correlated paternity and inbreeding with wider variation among individual tree outcrossing-rate estimates. Western hemlock had significant levels of correlated paternity only for the green tree and shelterwood treatments demonstrating family structuring inversely related to stand density. Inbreeding in western hemlock was significant but lower than that observed for amabilis fir with a J-shaped distribution for individual tree multilocus outcrossing-rate estimates. The pollination and dispersal mechanisms of the two species represent the most-likely factors causing these differences. Artificial regeneration may be utilized to augment the genetic resources of natural ingress.

Abies↗
PubMed1998

Genomic screen for QTLs underlying alcohol consumption in the P and NP rat lines.

Selective breeding for voluntary alcohol consumption was utilized to establish the alcohol-preferring (P) and alcohol-nonpreferring (NP) rat lines. Inbreeding was initiated after 30 generations of selection and, after 19 generations of inbreeding, 384 F2 intercross progeny were created to identify quantitative trait loci (QTLs) influencing alcohol consumption. We had reported previously a QTL on Chromosome (Chr) 4; additional markers genotyped on Chr 4 have increased the maximum lod score from 8.6 to 9.2. This QTL acts in an additive fashion and continues to account for approximately 11% of the phenotypic variability. The 95% confidence interval is 12.5 cM and includes the candidate gene, neuropeptide Y. Subsequent to the identification of the QTL on Chr 4, a genome scan was completed to identify additional QTLs influencing alcohol consumption. A lod score of 2.5 was obtained on Chr 3, syntenic to a region previously reported for alcohol preference in mice. Analysis of Chr 8 produced a lod score of 2.2 near the dopamine D2 and serotonin 1b receptors, which have been previously reported as candidate genes for alcohol preference. Evidence for linkage to alcohol consumption was not found on any other chromosome. It therefore appears likely that, in addition to the QTL on Chr 4, multiple loci of small to moderate effect, such as those on Chrs 3 and 8, underlie the difference in alcohol consumption in the P/NP lines.

Alcohol Drinking↗