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At least 235 records · Page 13Linked to original sources
PubMed1982

Quantitative genetics of skeletal nonmetric traits in the rhesus macaques of Cayo Santiago. III. Relative heritability of skeletal nonmetric and metric traits.

This study addresses the long-standing controversy in skeletal biology concerning the relative utility of skeletal metric and nonmetric traits for studies of biological relationship. This controversy centers on the relative heritability of these two trait sets. This paper presents heritabilities for a series of skeletal metric and nonmetric traits measured with the same sample of mother-offspring pairs from the Cayo Santiago skeletal collection of rhesus macaques. Skeletal nonmetric traits display significantly greater heritability estimates than metric traits. This difference is due primarily to the high heritability estimates of hyperostotic nonmetric traits. Foraminal traits are not significantly more heritable than skeletal metric traits. The generality of this pattern of heritability values, in which hyperostotic nonmetric traits are more highly heritable than foraminal nonmetric and metric traits, depends on future empirical study of the correlation of heritability values in populations and theoretical work.

Animals↗
PubMed1986

Quantitative genetics of cranial nonmetric traits in randombred mice: heritability and etiology.

Cheverud and Buikstra (1981) demonstrated a tendency for nonmetric traits representing the number of foramina to have lower heritabilities than those representing hyperstotic or hypostotic traits in a sample of rhesus macaques. Based on this observation, Cheverud and Buikstra hypothesize that differences in the heritability of the two sets of traits may be due to differences in trait etiology. This study addresses the proposed relationship between trait heritability and etiology. Heritability values are calculated for 35 cranial nonmetric traits in a sample of 320 randombred mice using analysis of variance. The results are minimally consistent with the etiological hypothesis, but only 4 of the 35 traits showed statistically significant heritability values. These results are discussed with reference to the assumption that nonmetric traits have a strong genetic component. It is concluded that the developmental pathways that genetic variation traverses before being expressed in the form of nonmetric traits must be understood before variation in nonmetric traits can be used to its fullest potential.

Animals↗
PubMed2006

Sifaka positional behavior: ontogenetic and quantitative genetic approaches.

In many primate species, hands and feet are large relative to neonatal body weight, and they subsequently exhibit negative allometric growth during ontogeny. Here, data are presented showing that this pattern holds for a wild population of lemur, Verreaux's sifaka (Propithecus verreauxi verreauxi). Using morphometric data collected on this population, it is shown that younger animals possess relatively large hands and feet. This ontogenetic pattern suggests a simple behavioral test: do juvenile animals with their larger, almost adult-sized hands and feet locomote on similarly sized substrates as adult animals? Using locomotor bout sampling, this question was tested by collecting positional behavior data on this population. Results from this test find no differences in locomotor behaviors or substrate use between yearlings and adult animals. To place these results in a broader evolutionary context, heritabilities and selection gradients of hands, feet, and other limb elements for animals in this population were estimated. Among limb elements, heritabilities range from 0.16-0.44, with the foot having the lowest value. Positive directional selection acts most strongly on the foot (directional selection gradient = 0.119). The low heritability and positive selection coefficient indicate that selection has acted, and continues to act, on foot size in young animals. These results are interpreted within a functional context with respect to the development of locomotor coordination: larger feet enable young animals to use "adult-sized" substrates when they move through their habitat. It is suggested that the widespread pattern of negative allometry of the extremities in sifaka and other primates is maintained by selection, and does not simply reflect a primitive developmental pathway that has no adaptive basis.

Animals↗
PubMed1992

The use of quantitative genetics for estimating the non-inherited and inherited contributions to metastasis formation.

The contribution of both non-inherited (stochastic, random, environmental, and other non-inherited influences) and inherited factors (genetic and inherited epigenetic factors) to the variability of spontaneous lung metastasis formation in over 100 metastatic lines from each of three murine tumors was measured. The contribution of inherited and genetic sources of variability to metastasis formation was significantly greater than 0 in all cases, but only in the lines of sarcoma SANH was it the major influence on metastatic variability. In the sarcoma SA4020 and hepatocarcinoma HCA-1 lines, non-inherited factors accounted for the majority of the variation in spontaneous lung metastasis formation. A similar situation was also observed in the variability of the tumors with respect to the diameter doubling time. In conclusion, both non-inherited and genetic/inherited factors significantly influenced the formation of spontaneous metastases in the tumors examined. The significance of this finding for the cloning of metastatic genes is discussed.

Animals↗
PubMed1991

A quantitative genetic analysis of tissue-specific catalase activity in Mus musculus.

Tissue-specific catalase activity in 3-week-old animals from inbred mouse strains 129/ReJ, BALB/c, C3H/HeAnl/Cas-1b, C3H/HeSnJ, C3H/S, C57BL/6J, and Swiss-Webster was found to be highly variable by analysis of variance (P = 0.01). Appropriate crosses were made among strains which were classified as normal (BALB/c, C3H/HeSnJ, C3H/S), hypocatalasemic (129/ReJ, C57BL/6J), and acatalasemic (C3H/HeAnl/Cas-1b) with respect to blood catalase activity to study the inheritance of the blood, kidney, liver, and lung catalase activity levels in a number of generations (reciprocal F1's, F2, two backcrosses--BC1 and BC2--and some RI lines). Segregation analysis and statistical methods which tested different models of inheritance as well as calculations of heritability were used in an effort to assess and evaluate genetic parameters that affect catalase activity. Results indicate that the inheritance of blood catalase activity in the cross involving acatalasemic and normal (BALB/c, C3H/HeSnJ) strains is compatible with the single-locus difference between the parental strains; however, the difference between the acatalasemic and the hypocatalasemic strain (C57BL/6J) would require additional genetic interaction for a satisfactory explanation. A similar pattern of generalization also applies to the inheritance of kidney catalase activity. The segregation pattern for the liver and lung catalase activity in most crosses is significantly different from the expectations of the single locus model. These results are compatible with the concept that a number of genes must affect tissue-specific catalase activity in mice. These may include previously described (e.g., Ce-1 and Ce-2) or novel genetic regulators/modifiers which interact with a single structural gene (Cas-1) or its product to produce the catalase phenotype characteristic of specific tissues in each strain.

Acatalasia↗
PubMed1989

Quantitative genetic analysis of longitudinal trends in adoption designs with application to IQ in the Colorado Adoption Project.

A factor model is presented that provides for either multivariate or developmental specification of longitudinal genetic and environmental effects in the presence of assortative mating and cultural transmission. Delta path methods are employed for the treatment of assortative mating and selective placement effects. The proportions of genetic and environmental variance and covariance attributable to assortative mating and cultural transmission are modeled explicitly. The model was applied to cognitive ability data on 493 families in the Colorado Adoption Project by means of maximum-likelihood pedigree analysis. A test of the assumption of multivariate normality of error provided an additional model criterion beyond the log-likelihood ratio statistic. No significant effects were found for cultural transmission, genetic-environmental covariance, or selective placement. The results suggest that the phenotypic stability of IQ during early childhood is largely, if not entirely, genetic in origin and that these longitudinal genetic effects can be represented most parsimoniously in the form of developmental transmission.

Adoption↗
PubMed1992

Quantitative genetic analysis of IQ development in young children: multivariate multiple regression with orthogonal polynomials.

The study of psychological development has recently benefited from innovative analytic methods for estimating and examining the correlates of individual growth curves. These methods are more consistent with a conceptualization of development as an ongoing, continuous process, rather than as increases or decreases in a trait between two discrete time points. Recent developmental behavior genetic models have focused on continuity and change in the genetic and environmental influences underlying phenotypes. In contrast, we present a model for genetic and environmental influences on phenotypic development per se. In this model, we adapted multiple regression methods developed for twin designs (DeFries and Fulker, 1985) to a parent-offspring adoption design and to a multivariate framework in which repeated measurements are decomposed into orthogonal polynomial trends. We applied these analyses to the development of IQ during infancy and early childhood using parent-offspring data from adoptive and nonadoptive families in the Colorado Adoption Project. The results suggested familial environmental influences on children's mean IQ for ages 1-4 but environmental influences specific to fathers' cognitive ability on children's IQ development. We also discuss advantages and disadvantages of the multivariate multiple regression method for studying genetic and environmental influences on development.

Adoption↗
PubMed2003

Quantitative-genetic analysis of wing form and bilateral asymmetry in isochromosomal lines of Drosophila subobscura using Procrustes methods.

Fluctuating asymmetry (FA) is often used as a measure of underlying developmental instability (DI), motivated by the idea that morphological variance is maladaptive. Whether or not DI has evolutionary potential is a highly disputed topic, marred by methodological problems and fuzzy prejudices. We report here some results from an ongoing study of the effects of karyotype, homozygosity and temperature on wing form and bilateral asymmetry using isochromosomal lines of Drosophila subobscura. Our approach uses the recently developed methodologies in geometric morphometrics to analyse shape configurations of landmarks within the standard statistical framework employed in studies of bilateral asymmetries, and we have extended these methods to partition the individual variation and the variation in asymmetries into genetic and environmental causal components. The analyses revealed temperature-dependent expression of genetic variation for wing size and wing shape, directional asymmetry (DA) of wing size, increased asymmetries at suboptimal temperature, and a transition from FA to DA in males as a result of increase in the rearing temperature. No genetic variation was generally detected for FA in our samples, but these are preliminary results because no crosses between lines were carried out and, therefore, the contribution of dominance was not taken into account. In addition, only a subset of the standing genetic variation was represented in the experiments.

Animals↗
PubMed2002

Pedigree-based quantitative genetic analysis of interindividual variation in circulating levels of IGFBP-3.

Circulating levels of insulin-like growth factor binding protein-3 (IGFBP-3) vary greatly between normal individuals, but until now little attention has been given to the study of the genetic factors involved in IGFBP-3 variability in healthy populations. The present study investigated the extent and pattern of the possible genetic influences on plasma levels of IGFBP-3 in 91 nuclear and more complex families, totaling 396 individuals (201 males and 195 females) of Caucasian ethnic origin. The variance decomposition analysis, was performed using the FISHER statistical package. In the second stage of the analysis, we used complex segregation analysis as implemented in the statistical package MAN. Significant negative correlation was revealed between age and plasma levels of IGFBP-3 in both sexes ( r=-0.49; r=-0.23; P<0.001). Multivariate analysis identified age, body weight, and height as significant covariates in men, but for women only age had a considerable effect. It has been demonstrated that about 57.7% of IGBP-3 variation adjusted for significant confounding factors was attributable to genetic factors. The results of bivariate variance decomposition analysis showed no significant genetic and phenotypic correlation between the mineral density of hand bones and IGFBP-3. Segregation analysis revealed the existence of a potential major gene effect that was able to explain some 27.5% of IGFBP-3 variation. Multifactorial effects, likely, unknown minor genes, contributed an additional 30% to IGFBP-3 variation. The segregation analysis also provided evidence of significant genotype X sex interaction in the determination of plasma levels of IGFBP-3.

Adolescent↗
PubMed1986

Quantitating genetic and nongenetic factors that determine plasma sex steroid variation in normal male twins.

We have observed that familial factors have a decided influence on the plasma content of sex steroids in men both in the general population and in men of families with prostatic cancer. The contribution of genetic and nongenetic familial factors on the variation of plasma sex steroid content and action has now been investigated in 75 pairs of normal male monozygotic (MZ) twins and 88 pairs of dizygotic (DZ) twins. Zygosity was determined by measuring ten blood proteins and enzymes. The mean plasma values for testosterone (T), dihydrotestosterone (DHT), estradiol (E2), estrone (E1), and 3 alpha-androstanediol glucuronide (3 alpha-diol G), free T, LH, FSH, SHBG, age, and degree of adiposity were all similar between the groups of twins. Familial factors (P less than 0.01) accounted for 50% or more of the variation in plasma hormone levels in MZ twins (3 alpha-diol G, 84%; T/DHT, 70%; T, 63%; E1, 63%; free T, 61%; E2, 57%; DHT, 56%; LH, 55%; and FSH, 54%) except for SHBG, which was 30%. The familial influence was greater in MZ twins than in DZ twins for all measurements except for SHBG. The heritability of the variation of hormone levels in plasma was determined from the equation: 2[rMZ(intraclass correlation) - rDZ]. Genes regulate 25% to 76% of the total variation of plasma content of the hormones except for DHT (12%) and SHBG (less than 1%). Genetic regulation of tissue DHT formation was suggested by observing a 48% genetic effect on the plasma content of 3 alpha-diol G.(ABSTRACT TRUNCATED AT 250 WORDS)

Dihydrotestosterone↗
PubMed2005

Quantitative genetic analysis of cellular adhesion molecules: the Fels Longitudinal Study.

Circulating concentrations of inflammatory markers predict cardiovascular disease (CVD) risk and are closely associated with obesity. However, little is known concerning genetic influences on serum levels of inflammatory markers. In this study, we estimated the heritability (h2) of soluble cellular adhesion molecule (sCAM) concentrations and examined the correlational architecture between different sCAMs. The study population included 234 men and 270 women aged 18-76 years, belonging to 121 families participating in the Fels Longitudinal Study. Serum levels of soluble intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), E-selectin (sESEL-1) and P-selectin (sPSEL-1) were assayed using commercially available kits. A variance components-based maximum likelihood method was used to estimate the h2 of the different serum inflammatory markers while simultaneously adjusting for the effects of known CVD risk factors, such as age and smoking. Additionally, we used bivariate extensions of these methods to estimate genetic and random environmental correlations among sCAMs. Levels of sCAMs were significantly heritable: h2=0.24+/-0.10 for sICAM-1, h2=0.22+/-0.10 for sVCAM-1, h2=0.50+/-0.11 for sESEL-1, and h2=0.46+/-0.10 for sPSEL-1. In addition, a significant genetic correlation (rho(G)=0.63) was found between sICAM-1 and sVCAM-1 indicating some degree of shared genetic control. In the Fels Longitudinal Study, the levels of four sCAMs are significantly influenced by genetic effects, and sICAM-1 shares a common genetic background with sVCAM-1.

Adolescent↗
PubMed1997

Quantitative genetics of serum sex hormone-binding globulin levels in participants in the San Antonio Family Heart Study.

Sex hormone-binding globulin (SHBG) is a steroid-binding plasma protein with a high affinity for testosterone that has been inversely associated with cardiovascular disease risk in many populations. SHBG may also act as a receptor in some tissues. Although the function of SHBG is relatively well understood, comparatively little is known about genetic factors contributing to the normal variation of serum SHBG levels. We estimated the heritability (h2) of serum SHBG levels in 717 related Mexican-Americans participating in the San Antonio Family Heart Study (SAFHS). We found a significant heritability (h2 = 0.31, P < .0001) for serum SHBG levels; age, exogenous hormones, smoking status, diabetic status, and adiposity showed significant associations (P < .05) with mean levels of SHBG. Sex was associated with mean SHBG levels but not with genetic or environmental variance in SHBG levels; heritability estimates were the same for males and females. These results indicate a significant genetic influence on SHBG in Mexican-Americans. Thus, SHBG may prove to be an important indicator of genetic risk for cardiovascular disease in this population, as well as others.

Adolescent↗