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PubMed1983

Yield and fertility relationships in dairy cattle.

Measures of yield and fertility were obtained from breeding receipts of artificial insemination and records of test-day yield. Estimates of heritability were by Henderson Method 3, maximum likelihood, and restricted maximum likelihood. Heritabilities for measures of yield varied, but most were within the range of earlier estimates. Measures of fertility had heritabilities from 0 to .03. Alternative upper bounds were placed on days open, number of services, and service period, and always the measure with the lesser bound had higher heritability for first parity. Measures of yield for early stages of lactation had slight positive phenotypic correlations with fertility whereas those for measures of cumulative yield later in lactation increased in relation to effect of gestation. Genetic correlations of first-parity yield and most measures of fertility were positive and less influenced by stage of lactation than phenotypic correlations. Antagonism moderated for second parity. Most genetic correlations were not significantly different from zero for third parity. Considerable genetic antagonism of yield and fertility may be of limited consequence because estimates of genetic variance of fertility were near zero.

Animals↗

PubMed1972

Long-term selection response for 12-day litter weight in mice.

Long-term selection for increased 12-day litter weight in two replicate lines (W(2), W(3)) of mice resulted in an apparent selection limit at about 17 generations. Quadratic polynomial and exponential models were fitted to the data in order to estimate the plateaued response and half-life of the selection process. Using the polynomial results, the half-life estimates were 4.5 and 8.6 generations for W(2) and W(3), respectively. The plateaued responses were 5.1 and 5.8 g which, when expressed in phenotypic standard deviation units, became 1.1 and 1.3. The exponential model provides similar estimates. A negative association between 12-day litter weight and fitness was not considered to be an adequate explanation for the plateau since there was no decrease in fertility of the selected lines. Evidence that exhaustion of genetic variability was not the cause of the plateau came from the immediate response to reverse selection. It was proposed that the plateau may be due to a negative genetic correlation between direct and maternal genetic effects, which would be expected to occur after many generations of selection. There were positive correlated responses in both replicates for adult body weight, which was in agreement with the positive genetic correlation between preweaning and postweaning body weight. The expected positive correlated response for number born was realized in only one of the replicates.

Animals↗

PubMed1994

Altered levels of erythrocyte calcium-binding proteins in essential hypertensives with genetic predisposition: correlation with ambulatory blood pressure.

OBJECTIVE: To examine whether changes in calcium-binding proteins, one of the components of the calcium ion handling mechanism, occur in humans with essential hypertension. DESIGN: We measured the levels of cytosolic calcium-binding proteins purified from human erythrocytes using a felodipine fluorescence assay, and examined the correlation between this parameter and the ambulatory blood pressure (ABP). We divided 127 subjects into four age-matched groups according to their mean ABP levels and whether they had a family history of both hypertension and stroke [group A hypertensives with a positive family history (n = 30), group B hypertensives with no family history (n = 31), group C normotensives with a family history (n = 31) and group D normotensives with no family history (n = 35) of hypertension and stroke]. RESULTS: The erythrocyte cytosolic level of calcium-binding proteins in group A was significantly lower than that in group B, as was that in group C compared with group D. There was no significant correlation between the erythrocyte level of calcium-binding proteins and casual blood pressure values in any group. However, in group A significant negative correlations between the erythrocyte level of calcium-binding proteins and systolic and mean ABP were observed (r = -0.34, P < 0.05 and r = -0.39, P < 0.05, respectively). No significant correlations between the ABP and erythrocyte levels of calcium-binding proteins were observed in the other groups. When each group was subdivided according to sex, there were significant negative correlations between the erythrocyte level of calcium-binding proteins and the systolic and mean ABP in the males of groups A and C, but no correlations were found in any of the female subgroups or the males of groups B and D. Reducing the blood pressure by antihypertensive drug therapy did not affect the erythrocyte calcium-binding proteins level in 13 patients from groups A and B. Analysis using anion-exchange fast-performance liquid chromatography on a Mono-Q column and sodium dodecyl sulphate-polyacrylamide gel electrophoresis revealed that the calcium-binding proteins in human erythrocytes, the levels of which were low in group A, formed a single protein band with a molecular weight of 17,000, which was assumed to be a calmodulin. CONCLUSIONS: These results suggest that there are subgroups of hypertensive patients with low erythrocyte cytosolic levels of calcium-binding proteins, which are genetically determined. Furthermore, our data suggest that the erythrocyte level of calcium-binding proteins and ABP in male subjects with hypertension and normotensives with a genetic predisposition are correlated strongly, whereas no such correlation was observed in any female subgroup. This indicates that the regulatory mechanism or mechanisms involved in the control of blood pressure in men and women may be different.

Aging↗

PubMed1998

The U.S. National Sheep Improvement Program: across-flock genetic evaluations and new trait development.

The U.S. National Sheep Improvement Program (NSIP) began in 1987 to provide within-flock genetic evaluations for the American sheep industry. An evaluation of operating procedures and methodology for NSIP began in 1993 and has resulted in across-flock, multiple-trait EPD for three breeds: Targhee, Suffolk, and Polypay. Traits reported in the across-flock analyses included direct and maternal effects on weaning weight in all breeds, postweaning weight at 120 d in Suffolk and Polypay and at 365 d in Targhee, greasy fleece weight in Targhee and Polypay, and wool fiber diameter in Targhee. Number born per ewe lambing was also evaluated in single-trait analyses for all breeds. Genetic parameters were derived separately for each breed. Important genetic antagonisms include an unfavorable genetic correlation of .51 between fleece weight and fiber diameter in Targhee and a genetic correlation of -.55 between direct and maternal effects on weaning weight in Polypay. Estimates of genetic trends between 1987 and 1995 were consistent with perceived breed roles. In Targhee, direct and maternal effects on body weights increased, fiber diameter declined, fleece weight was maintained, and number born declined. In Suffolk, direct effects on body weight increased, but number born and maternal effects on weaning weight did not change. In Polypay, number born and maternal contributions to weaning weight increased, but direct genetic merit for body weight declined. Prospective enhancements to NSIP include methods for genetic evaluation of performance in accelerated lambing and of carcass leanness and development of breeding objectives and selection aids for various production systems.

Animals↗

PubMed2001

Genetic variation in stimulated GH release and in IGF-I of young dairy cattle and their associations with the leucine/valine polymorphism in the GH gene.

Genetic variations in plasma GH concentrations before and following thyrotropin-releasing hormone (TRH) stimulation and in IGF-I concentrations were studied in 11-mo-old Polish Friesian cattle (104 heifers and 110 bulls). A possible association between stimulated GH release, IGF-I, and the polymorphism in the GH gene causing substitution of leucine-Leu to valine-Val at amino acid position 127 of the protein was also investigated. The GH concentrations were determined in serial plasma samples collected every 15 min from 15 min before to 135 min after intravenous administration of 0.15 microg TRH/kg live weight. The analysis was performed on three variables: baseline (mean of samples at -15 and 0 min), peak (sample at 15 min after injection) and rate (peak minus sample at 60 min, divided by 45 min). The IGF-I concentrations were measured in plasma samples taken before the TRH stimulation. Additionally, first lactation records from the 75 cows earlier tested for GH release and IGF-I were used to study a possible association of milk production traits with GH genotypes. The data were analyzed by multivariate mixed linear models. The heritability of IGF-I reached a higher value (0.35) than variables baseline, peak, and rate (0.02, 0.14, and 0.14, respectively). The GH variables were positively genetically correlated with each other (0.22 to 0.93), whereas they had negative genetic correlations with IGF-I (-0.26). The Val/Val genotypes reached the highest peak value compared with other GH genotypes (P > 0.01), whereas the Leu/Leu genotypes had the highest IGF-I concentrations (P < or = 0.05). Moreover, the Leu/Val heterozygotes were superior to others in milk and protein yields, whereas the Leu/Leu homozygotes reached the highest fat yield (P > or = 0.01). We conclude that GH peak, GH rate, and IGF-I are heritable traits in young dairy cattle and are affected by the Leu/Val polymorphism in the GH gene.

Alleles↗

PubMed1992

Genetic and environmental relationships among somatic cell count, bacterial infection, and clinical mastitis.

Incidence of bacterial infection in 9784 lactations of 7763 cows in 31 herds, SCC in 32,448 lactations of 19,764 cows from 54 herds, and incidence of first parity mastitis recorded in the first lactations of 148,143 cows in 828 herds were analyzed. Bacterial infection was analyzed dichotomously by both threshold and linear models. The effects of parity, season, stage of lactation, and parity by stage of lactation interaction on SCC were estimated. Heritability of mean lactation log SCC--corrected for the effects of parity, season, and stage of lactation--varied from .13 to .27 for all parities in different data sets. Heritability of bacterial infection was .04 for the threshold model and .02 for the linear models. Heritability of field-recorded mastitis was .01. The genetic correlation between bacterial infection and SCC was near unity, but the genetic correlation between SCC and mastitis was .3. Selection for lowered SCC should reduce incidence of bacterial infection by 2% per unit of selection intensity.

Animals↗

PubMed2005

Mitochondrial genetic effects on latent class variables associated with susceptibility to alcoholism.

We report the results of statistical genetic analyses of data from the Collaborative Study on the Genetics of Alcoholism prepared for the Genetic Analysis Workshop 14 to detect and characterize maternally inherited mitochondrial genetic effects on variation in latent class psychiatric/behavioral variables employed in the diagnosis of alcoholism. Using published extensions to variance decomposition methods for statistical genetic analysis of continuous and discrete traits we: 1) estimated the proportion of the variance in each trait due to the effects of mitochondrial DNA (mtDNA), 2) tested for pleiotropy, both mitochondrial genetic and residual additive genetic, between trait pairs, and 3) evaluated whether the simultaneous estimation of mitochondrial genetic effects on these traits improves our ability to detect and localize quantitative trait loci (QTL) in the nuclear genome. After correction for multiple testing, we find significant (p < 0.009) mitochondrial genetic contributions to the variance for two latent class variables. Although we do detect significant residual additive genetic correlations between the two traits, there is no evidence of a residual mitochondrial genetic correlation between them. Evidence for autosomal QTL for these traits is improved when linkage screens are conditioned on significant mitochondrial genetic effects. We conclude that mitochondrial genes may contribute to variation in some latent class psychiatric/behavioral variables associated with alcoholism.

Alcoholism↗

PubMed2025

The genetic architecture of fibromyalgia across 2.5 million individuals.

Fibromyalgia is a common and debilitating chronic pain syndrome of poorly understood etiology. Here, we conduct a multi-ancestry genome-wide association study meta-analysis across 2,563,755 individuals (54,629 cases and 2,509,126 controls) from 11 cohorts, identifying the first 26 risk loci for fibromyalgia. The strongest association was with a coding variant in HTT, the causal gene for Huntington's disease. Gene prioritization implicated the HTT regulator GPR52, as well as diverse genes with neural roles, including CAMKV, DCC, DRD2/NCAM1, MDGA2, and CELF4. Fibromyalgia heritability was exclusively enriched within brain tissues and neural cell types. Fibromyalgia showed strong, positive genetic correlation with a wide range of chronic pain, psychiatric, and somatic disorders, including genetic correlations above 0.7 with low back pain, post-traumatic stress disorder and irritable bowel syndrome. Despite large sex differences in fibromyalgia prevalence, the genetic architecture of fibromyalgia was nearly identical between males and females. This work provides the first robust genetic evidence defining fibromyalgia as a central nervous system disorder, thereby establishing a biological framework for its complex pathophysiology and extensive clinical comorbidities.

Journal Article↗

PubMed2005

Study of codes of disposal at different parities of Large White sows using a linear censored model.

To study the genetic relationship between three grouped reasons for sow removal (SR) in consecutive parities, accounting for censoring, 13,838 records from Large White sows were analyzed. Data were from seven pure-line farms having, on average, 5.9% unknown SR. Three traits were subjectively defined, each corresponding to a classification of SR (reproductive [RR], nonreproductive [RN], and others [RO]). Records for each trait could take one of five categories, according to parity at removal (0 to 4 or later). A multivariate linear censored model was implemented. The model to estimate (co)variance components and parameters included the effects of year-season, region, contemporary group, and additive genetic effects. The most common SR was related to reproduction (48.5%). Diseases of different origin and cause, old age/parity, and sow death or loss accounted for about 18, 7, and 4% of total culls, respectively. Estimates of variance components showed heterogeneity of additive genetic and residual variances for the three traits. Estimates of heritability were 0.18, 0.13, and 0.15 for RR, RN, and RO, respectively. Genetic correlations between removal codes were high (> or =0.90). Results suggest sizeable additive genetic variances exist for parity at removal and different codes of removal. Different SR reasons seem to operate similarly or as a closely related genetic trait associated with fitness. In particular, RN and RO seem to be genetically indistinguishable. Data structure, definition, and volume are major limitations in studies of sow survival. A multiple-trait censored model is preferred to evaluate reasons of sow disposal. Grouped removal causes seem to be strongly genetically correlated but with heterogeneous variances, suggesting that combining all removal causes and treating the trait as parity at disposal is an alternative approach.

Animal Husbandry↗

PubMed1981

Quantitative genetics of skeletal nonmetric traits in the rhesus macaques on Cayo Santiago. II. Phenotypic, genetic, and environmental correlations between traits.

The general lack of phenotypic correlation among skeletal nonmetric traits has been interpreted as indicating a lack of genetic correlation among these traits. Nonmetric traits scored on animals in the skeletal collection of rhesus macaques from Cayo Santiago are used to calculate phenotypic, genetic, and environmental correlations between traits. The results show that even when phenotypic correlations are low, there may be large, significant genetic correlations among these traits. The genetic correlation pattern suggests that genes which affect nonmetric trait variation act primarily at a local level in the cranium, even though there are genes with pleiotropic effects on skeletal nonmetric traits throughout the cranium. Environmental and phenotypic correlations do not show this neighborhood pattern of correlation.

Animals↗

PubMed2006

Foot pad dermatitis and hock burn in broiler chickens and degree of inheritance.

A total of 2,118 birds from 2 strains were allocated to 12 groups of 93 to 100 each in 2 time-separated replicates. The development of foot pad dermatitis (FPD) and hock burn (HB) were recorded weekly from d 8 to slaughter on a set sample of live animals (7 per group). In addition, feet and hocks of all birds were investigated at slaughter at either 4, 6 (fast-growing strain), 8, or 10 (slow-growing strain) wk of age. Lesions were scored for both the left and right foot and classified according to a scale from 1 (no lesion) to 9 (very severe lesions) for FPD and from 1 (no lesion) to 3 (very severe lesions) for HB. No FPD lesions and very few low-grade HB lesions were found in chickens from the slow-growing strain. In the fast-growing strain, the first signs of FPD and HB were seen in wk 2. The incidence of both types of lesions increased thereafter. Foot pad dermatitis was more frequent in females (49 vs. 36%, P < 0.05). Body weight did not affect FPD, but more HB were found at higher BW (P < 0.01). Egg weight influenced neither FPD nor HB. Variance and covariance components were analyzed using a multivariate animal model, in which scores for FPD and HB were transformed into logarithmic scale. The analyses were carried out using restricted maximum likelihood algorithm. Heritabilities were estimated to be 0.31 +/- 0.12 (SE) for FPD, 0.08 +/- 0.08 for HB, and 0.38 +/- 0.13 for BW. Genetic correlations among these traits were low and nonsignificant. Phenotypic correlation between BW and FPD was low and nonsignificant and between BW and HB was 0.17 +/- 0.05 (P < 0.01). The relative high heritability of FPD and the low genetic correlation to BW suggested that genetic selection against susceptibility to FPD should be possible without negative effects on BW gain.

Analysis of Variance↗

PubMed1992

Divergent selection for exponential growth rate at fourteen or forty-two days of age. 1. Early responses.

Athens-Canadian randombred chickens were divergently selected for exponential growth rate (EGR) to 14 or 42 days of age, resulting in four unique populations: 14L, 14H, 42L, and 42H. Exponential growth rate was calculated as: EGR = [ln b-ln a] + t; where a = hatching weight; b = weight at age of selection; and t = age of selection. In the S4 generation, 14H chicks had significantly greater EGR than 42H chicks at 14 but not 42 days. Chicks from the 42H line had significantly greater EGR than 14H chicks from 14 to 42 days. This meant that 14H chicks were significantly heavier than 42H chicks at 14 but not 42 days. Indeed, 14H chicks were consistently 5 to 10% heavier than the 42H chicks in each generation. Selection for EGR at 14 days was at least as effective in altering 42-day body weight as selection for growth rate at that age during the early generations of selection. Evidence of asymmetry existed for selection for EGR at 14 but not 42 days. Realized heritability of fast EGR14 was .29 +/- .08 (SE) whereas that of fast EGR42 was .15 +/- .09. Genetic correlation between fast EGR14 and fast EGR42 was 1.45, whereas the converse genetic correlation was .67. This would suggest that all the genes that influence 14-day growth influence 42-day growth, but not vice versa. Growth curve analysis supported the general hypothesis of growth, in that instantaneous growth rate was fastest in the 14H line, as was the decay of growth. Indeed, 14H birds were smaller at and beyond sexual maturity than 42H chickens.

Aging↗

PubMed2026

Common genetic variants are associated with increased likelihood of latent co-occurring neurodevelopmental and mental health factors among autistic individuals.

Autistic individuals show elevated rates of co-occurring neurodevelopmental and mental health conditions, yet the genetic architecture of those comorbidities remains unclear. Using phenotypic (N = 74,204) and genetic (N = 17,582) data from the SPARK study, we investigated the factor structure, heritability, genetic correlation with autism (pleiotropy) and corresponding conditions in the general population (additivity). First, confirmatory factor analysis identified three correlated factors mirroring general population patterns: behavioural (ADHD, disruptive behaviour disorders), cothymic (depression, anxiety), and thought disorder (schizophrenia, bipolar). Second, all three factors had significant SNP heritabilities whilst rare variants were not associated with the tested factors in our sample. Third, polygenic scores and genetic correlations revealed positive shared genetics between the three factors and corresponding conditions in the general population but not with autism, supporting the additivity hypothesis. Fourth, within-family analyses (N = 5236 trios) demonstrated direct but not indirect genetic effects for the behavioural and cothymic factors. In sum, we find evidence for additive effects of other genetic factors in contributing to some latent co-occurring neurodevelopmental and mental health conditions in autism.

Journal Article↗

PubMed1985

Influencing prolificacy of sows by selection for physiological factors.

The potential to improve prolificacy, with major emphasis on selection for components of litter size, ovulation rate and prenatal survival, and selection for physiological factors are reviewed. Response to selection for physiological factors is superior to direct selection if physiological factors have moderate heritabilities and moderate to high genetic correlations with the trait to be improved. There are very few estimates of the genetic parameters needed to calculate the relative efficiency of direct and indirect selection. Testis size is highly heritable and positively correlated genetically with ovulation rate in both mice and pigs and may be potentially useful in an index with litter size to improve ovulation rate and prenatal survival. Selection for growth, ovulation rate or litter size has increased ovulation rate in mice, but the physiological explanations are different. Selection for litter size in a line of pigs previously selected for ovulation rate was effective; the realized heritability was 0.18 +/- 0.06. Potential improvements in litter size from index selection for ovulation rate and prenatal survival are discussed and compared to direct selection for litter size.

Animals↗

PubMed2004

A twin study of early cannabis use and subsequent use and abuse/dependence of other illicit drugs.

INTRODUCTION: Cannabis use is strongly associated with the use and abuse/dependence of other illicit drugs. Gateway and common liabilities models have been employed to explain this relationship. We sought to examine this association using a combination of the discordant twin design and modeling methods. METHOD: We assess the relationship between early cannabis use and the subsequent use and abuse/ dependence of other illicit drugs in a population-based sample of male and female twin pairs using four analyses: (i) analysis of the association between early cannabis use and other illicit drug use and abuse/dependence in the entire sample of twins, (ii) assessment of the influence of early cannabis use in twin 1 on twin 2's use or abuse/dependence of other illicit drugs, (iii) use of twin pairs discordant for early cannabis use in a discordant twin design and (iv) a model-fitting procedure. RESULTS: We found: (i) a strong association between early cannabis use and use and abuse/dependence of other illicit drugs in the sample, (ii) twin 1's early cannabis use is significantly associated with the twin 2's other illicit drug use, (iii) the role of correlated genetic factors with some evidence for a causal influence, and (iv) the correlated liabilities model fits the data well. CONCLUSIONS: Early cannabis use is strongly associated with other illicit drug use and abuse/dependence. The relationship arises largely due to correlated genetic and environmental influences with persisting evidence for some causal influences.

Adult↗

PubMed2001

Resistance or emigration: response of the high-alpine plant Eritrichium nanum (L.) Gaudin to the ice age within the Central Alps.

Two main possibilities regarding glacial survival of the mountain flora of the Alps during the Quaternary have been discussed: the tabula rasa and the nunatak hypotheses. Eritrichium nanum (L.) Gaudin (Boraginaceae) is a perennial cushion plant, occurring at high elevations of the Central Alps and having a preference for extreme habitats. It belongs to a group of high-alpine plants, for which in situ glacial survival on nunataks is ecologically possible. By investigating 20 populations of E. nanum of potential nunatak and peripheral refugial regions using amplified fragment length polymorphism, considerable genetic differences between populations from the Central Alps and populations from peripheral refugia were detected; hence, the latter probably did not serve as potential sources for the re-colonization of the Central Alps after glaciation. Genetic variation was hierarchically structured (AMOVA), and three genetically distinct regions could be identified in the Central Alps. Two of these, the Penninic and Rhaetic Alps, correspond to nunatak regions proposed in the biogeographic literature. Populations from the Lepontic Alps formed a third genetic group. Genetic correlation (Mantel statistics) was highest within populations, with a modest decline among populations within specific nunatak regions and a negative correlation outside the genetic influence of specific nunatak regions. In situ glacial survival in E. nanum could be a model for the Quaternary history of other alpine plants, especially those that also occur at high elevations and in similar habitats.

Altitude↗

PubMed1997

Gender-specific regional changes in genetic structure of muscularity in early adolescence.

Genetic and environmental influences on muscle circumference measurements of the extremities were estimated in 105 pairs of twins between 10 and 14 yr of age. Four circumferences, extended upper arm (EAC), forearm (FC), thigh (TC), and calf (CC), were measured. Univariate model fitting revealed that the largest part (87-95%) of the variance for all circumferences at most ages was explained by additive genetic factors. Sex differences were observed for some age categories. Multivariate analyses showed a different pattern evolving according to age and gender. In boys from 10 to 12 yr of age, one general genetic factor influenced all four circumferences. With increasing age, an arm-leg model emerged, one genetic factor influencing the arm and another genetic factor the leg circumferences. In young girls one genetic factor loaded on the proximal (EAC, TC) and another on the distal (FC, CC) circumferences. With subjects at age 14 yr, an arm-leg model was observed. High genetic correlations indicated that genetic factors related to EAC, FC, TC, and CC did not act independently. The age-and gender-specific changes in the genetic structure suggest pubertal influences. This study shows that muscle circumferences are highly heritable characteristics and are therefore a promising starting point at which to locate their genes. Gene mapping could validate the gender-specific change of the genetic structure with age and region.

Adolescent↗

PubMed2004

Evidence for genetic control of adult weight plasticity in the snail Helix aspersa.

Phenotypic plasticity and canalization are important topics in quantitative genetics and evolution. Both concepts are related to environmental sensitivity. The latter can be modeled using a model with genetically structured environmental variance. This work reports the results of a genetic analysis of adult weight in the snail Helix aspersa. Several models of heterogeneous variance are fitted using a Bayesian, MCMC approach. Exploratory analyses using posterior predictive model checking and model comparisons based on the deviance information criterion favor a model postulating a genetically structured heterogeneous environmental variance. Our analysis provides a strong indication of a positive genetic correlation between additive genetic values affecting the mean and those affecting environmental variation of adult body weight. The possibility of manipulating environmental variance by selection is illustrated numerically using estimates of parameters derived from the snail data set.

Animals↗