scholarly journals ANALYSIS OF THE COVARIANCE STRUCTURE OF DIGITAL RIDGE COUNTS IN THE OFFSPRING OF MONOZYGOTIC TWINS

Genetics ◽  
1983 ◽  
Vol 103 (3) ◽  
pp. 495-512
Author(s):  
Rita M Cantor ◽  
Walter E Nance ◽  
Lindon J Eaves ◽  
Phyllis M Winter ◽  
Marsha M Blanchard
Keyword(s):  
Model Fitting ◽  
Monozygotic Twins ◽  
Covariance Structure ◽  
Monozygotic Twin ◽  
Analysis Of Covariance ◽  
General Factor ◽  
Fitting Procedure ◽  
Rigorous Testing ◽  
The Individual ◽  
Nested Analysis

ABSTRACT Improved methods for analysis of covariance structures now permit the rigorous testing of multivariate genetic hypotheses. Using Jöreskog's Lisrel IV computer program we have conducted a confirmatory factor analysis of dermal ridge counts on the individual fingers of 509 offspring of 107 monozygotic twin pairs. Prior to the initiation of the model-fitting procedure, the sex-adjusted ridge counts for the offspring of male and female twins were partitioned by a multivariate nested analysis of variance yielding five 10 ×10 variance-covariance matrices containing a total of 275 distinctly observed parameters with which to estimate latent sources of genetic and environmental variation and test hypotheses about the factor structure of those latent causes. To provide an adequate explanation for the observed patterns of covariation, it was necessary to include additive genetic, random environmental, epistatic and maternal effects in the model and a structure for the additive genetic effects which included a general factor and allowed for hand assymmetry and finger symmetry. The results illustrate the value of these methods for the analysis of interrelated metric traits.

scholarly journals The heritability of coronal and sagittal phenotype in idiopathic scoliosis: a report of 12 monozygotic twin pairs

2020 ◽  
Vol 9 (1) ◽  
pp. 51-55
Author(s):  
Tom P. C. Schlösser ◽  
Ane Simony ◽  
Paul Gerdhem ◽  
Mikkel Ø. Andersen ◽  
René M. Castelein ◽  
...  
Keyword(s):  
The Netherlands ◽  
Idiopathic Scoliosis ◽  
Lumbar Lordosis ◽  
Thoracic Kyphosis ◽  
Monozygotic Twins ◽  
Monozygotic Twin ◽  
Sagittal Profile ◽  
Curve Type ◽  
Sagittal Parameters ◽  
The Individual

Abstract Purpose One of the pathways through which genetics may act in the causation of idiopathic scoliosis is inheritance of a specific sagittal profile that predisposes for its development. In this study, coronal and sagittal parameters were compared in an international collection of monozygotic twins with idiopathic scoliosis. Methods Twelve monozygotic twin pairs who underwent biplanar radiography for idiopathic scoliosis were systematically identified in existing scoliosis databases in The Netherlands, Sweden, and Denmark. On the first available radiographs, the coronal and sagittal curve parameters (Roussouly and Abelin types, thoracic kyphosis, lumbar lordosis and length of the posteriorly inclined segment) were determined. Results In all 12 monozygotic twin pairs, both twins were affected by AIS. Four (33%) twin pairs had similar coronal and sagittal spinal phenotype, whereas two (17%) had different coronal phenotype and similar sagittal profiles, and six (50%) pairs had different coronal as well as sagittal phenotype. Conclusions Analysis of biplanar curve characteristics in monozygotic twins showed that all twin pairs were affected by idiopathic scoliosis. However, only 33% of the pairs had similar coronal and sagittal spinal phenotypes. Based on this limited dataset, the hypothesis can be formulated that besides genetic pre-disposition, the individual (inherited) sagittal profile plays a role in the development of different coronal curve type.

Effects of Maternal Nutrient Restriction During Gestation on LH Production in the Female Bovine Fetus

2021 ◽  
Vol 99 (Supplement_2) ◽  
pp. 25-26
Author(s):  
Sterling H Fahey ◽  
Sarah West ◽  
John M Long ◽  
Carey Satterfield ◽  
Rodolfo C Cardoso
Keyword(s):  
Protein Content ◽  
Fetal Development ◽  
Monozygotic Twins ◽  
Late Gestation ◽  
Nutrient Restriction ◽  
Western Blots ◽  
Physiological Processes ◽  
Individual Potential ◽  
The Individual

Abstract Gestational nutrient restriction causes epigenetic and phenotypic changes that affect multiple physiological processes in the offspring. Gonadotropes, the cells in the anterior pituitary that secrete luteinizing hormone (LH) and follicle-stimulating hormone (FSH), are particularly sensitive to nutritional changes during fetal development. Our objective herein was to investigate the effects of gestational nutrient restriction on LH protein content and number of gonadotropes in the fetal bovine pituitary. We hypothesized that moderate nutrient restriction during mid to late gestation decreases pituitary LH production, which is associated with a reduced number of gonadotropes. Embryos were produced in vitro with X-bearing semen from a single sire then split to generate monozygotic twins. Each identical twin was transferred to a virgin dam yielding four sets of female twins. At gestational d 158, the dams were randomly assigned into two groups, one fed 100% NRC requirements (control) and the other fed 70% of NRC requirements (restricted) during the last trimester of gestation, ensuring each pair of twins had one twin in each group. At gestational d 265, the fetuses (n = 4/group) were euthanized by barbiturate overdose, and the pituitaries were collected. Western blots were performed using an ovine LH-specific antibody (Dr. A.F. Parlow, NIDDK). The total LH protein content in the pituitary tended to be decreased in the restricted fetuses compared to controls (P < 0.10). However, immunohistochemistry analysis of the pituitary did not reveal any significant changes in the total number of LH-positive cells (control = 460±23 cells/0.5 mm2; restricted = 496±45 cells/0.5 mm2, P = 0.58). In conclusion, while maternal nutrient restriction during gestation resulted in a trend of reduced LH content in the fetal pituitary, immunohistological findings suggest that these changes are likely related to the individual potential of each gonadotrope to produce LH, rather than alterations in cell differentiation during fetal development.

scholarly journals The genetical analysis of covariance structure

Heredity ◽  
1977 ◽  
Vol 38 (1) ◽  
pp. 79-95 ◽  
Author(s):  
N G Martin ◽  
L J Eaves
Keyword(s):  
Covariance Structure ◽  
Analysis Of Covariance ◽  
Genetical Analysis

scholarly journals Effectiveness of the Nutritional App “MyNutriCart” on Food Choices Related to Purchase and Dietary Behavior: A Pilot Randomized Controlled Trial

Nutrients ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1967 ◽  
Author(s):  
Cristina Palacios ◽  
Michelle Torres ◽  
Desiree López ◽  
Maria Trak-Fellermeier ◽  
Catherine Coccia ◽  
...  
Keyword(s):  
Controlled Trial ◽  
Intervention Group ◽  
Smartphone Application ◽  
Analysis Of Covariance ◽  
Baseline Body Mass Index ◽  
Traditional Group ◽  
Face To Face ◽  
Cured Meats ◽  
Food Recalls ◽  
The Individual

Objective: To pilot test the effectiveness of “MyNutriCart”, a smartphone application (app) that generates healthy grocery lists, on diet and weight. Methods: A pilot randomized trial was conducted to test the efficacy of using the “MyNutriCart” app compared to one face-to-face counseling session (Traditional group) in Hispanic overweight and obese adults. Household food purchasing behavior, three 24-h food recalls, Tucker’s semi-quantitative food frequency questionnaire (FFQ), and weight were assessed at baseline and after 8 weeks. Statistical analyses included t tests, a Poisson regression model, and analysis of covariance (ANCOVA) using STATA. Results: 24 participants in the Traditional group and 27 in the App group completed the study. Most participants were women (>88%), with a mean age of 35.3 years, more than a high school education (>80%), a family composition of at least three members, and a mean baseline body mass index (BMI) of 34.5 kg/m2. There were significant improvements in household purchasing of vegetables and whole grains, in individual intakes of refined grains, healthy proteins, whole-fat dairies, legumes, 100% fruit juices, and sweets and snacks; and in the individual frequency of intake of fruits and cold cuts/cured meats within the intervention group (p < 0.05). However, no significant differences were found between groups. No changes were detected in weight. Conclusions: “MyNutriCart” app use led to significant improvements in food-related behaviors compared to baseline, with no significant differences when compared to the Traditional group. Cost and resource savings of using the app compared to face-to-face counseling may make it a good option for interventionists.

Associations between insulin-like growth factor-I (IGF-I), IGF-binding protein-1, insulin and other metabolic measures after controlling for genetic influences: results from middle-aged and elderly monozygotic twins

1997 ◽  
Vol 153 (2) ◽  
pp. 251-257 ◽  
Author(s):  
Y Hong ◽  
K Brismar ◽  
K Hall ◽  
N L Pedersen ◽  
U de Faire
Keyword(s):  
Genetic Variation ◽  
Growth Factor ◽  
Monozygotic Twins ◽  
Monozygotic Twin ◽  
Genetic Influences ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Igf Binding ◽  
Igf Binding Protein

Abstract It has previously been shown that the serum levels of insulin-like growth factor-I (IGF-I), IGF-binding protein-1 (IGFBP-1), and insulin are influenced by genetic effects to various degrees. From a clinical and preventive point of view, however, it is important to identify potentially modifiable non-genetic factors influencing the levels of these measures. Because monozygotic twin pairs share the same genetic background, differences in phenotypic levels within monozygotic twin pairs are believed to be due to non-genetic influences. Accordingly, the associations between intrapair differences in one phenotype and intrapair differences in another phenotype are also due to non-genetic influences. The present sample of 97 pairs of monozygotic twins from the population-based Swedish Adoption/Twin Study of Aging (SATSA) provided the opportunity to assess non-genetic influences on the levels of IGF-I, IGFBP-1, and insulin. Several metabolic measures were found to account for the variation of IGF-I, IGFBP-1, and insulin after controlling for the genetic influences. IGFBP-1 and glucose were significant predictors for the levels of IGF-I. IGFBP-1 and glucose together explained about one quarter of the non-genetic variation of IGF-I. However, when IGFBP-1 was dropped from the regression model, insulin was the only independent predictor of IGF-I, and explained about 19% of the non-genetic variation for IGF-I. For IGFBP-1, insulin and IGF-I were the significant non-genetic predictors. Insulin and IGF-I explained about 28 and 8% respectively of the non-genetic variation for IGFBP-1, while for insulin, IGF-I, triglycerides, body height, glucose, and body mass index (BMI) explained approximately 20, 12, 6, 5 and 5% respectively of the non-genetic variation. Journal of Endocrinology (1997) 153, 251–257

scholarly journals A Reevaluation of the 1990 “Minnesota Study of Twins Reared Apart” IQ Study

2022 ◽  
Author(s):  
Jay Joseph
Keyword(s):  
Cognitive Ability ◽  
Genetic Factors ◽  
Model Fitting ◽  
Monozygotic Twin ◽  
Cohort Effects ◽  
Genetic Influences ◽  
Control Group ◽  
Dizygotic Twin ◽  
Full Sample ◽  
Iq Scores

In 1990, Thomas J. Bouchard, Jr. and colleagues published the widely cited 1990 “Minnesota Study of Twins Reared Apart” (MISTRA) Science IQ study. To arrive at the conclusion that “IQ is strongly affected by genetic factors,” Bouchard and colleagues omitted their control group reared-apart dizygotic twin (“DZA”) IQ-score correlations. Near-full-sample correlations published after the study’s 2000 endpoint show that the reared-apart monozygotic twin (“MZA”) and DZA group IQ correlations did not differ at a statistically significant level, suggesting that the study failed the first step in determining that IQ scores are influenced by heredity. After bypassing the model-fitting technique they used in most non-IQ MISTRA studies, the researchers assumed that the MZA group IQ-score correlation alone “directly estimates heritability.” This method was based on unsupported assumptions by the researchers, and they largely overlooked the confounding influence of cohort effects. Bouchard and colleagues then decided to count most environmental influences they did recognize as genetic influences. I conclude that the MISTRA IQ study failed to discover genetic influences on IQ scores and cognitive ability across the studied population, and that the study should be evaluated in the context of psychology’s replication problem.

scholarly journals Articulatory and acoustic inter-speaker variability in the production of German vowels

2010 ◽  
Vol 52 ◽  
pp. 19-42
Author(s):  
Melanie Weirich
Keyword(s):  
Genetic Similarity ◽  
Strong Influence ◽  
Monozygotic Twins ◽  
Monozygotic Twin ◽  
Shared Environment ◽  
Acoustic Similarity ◽  
Speaker Variability ◽  
Electromagnetic Articulography ◽  
Shared Time ◽  
The Impact

This study examines articulatory and acoustic inter-speaker variability in the production of the German vowels /i/, /u/ and /a/. Our subjects are 3 monozygotic twin pairs (2 female and 1 male pair) and 2 dizygotic female twin pairs. All of them were born, raised and are still living in Berlin and see their twin brother or sister regularly. We assume that monozygotic twins that are genetically identical and share the same physiology should be more similar in their articulation than dizygotic twins but that the shared time and social environment of twins, regardless of their genetic similarity, also plays a crucial role in the acoustic similarity of twins. Articulatory measurements were made with EMA (Electromagnetic Articulography) and the target positions of the produced vowels were analyzed. Additionally, the formants F1-F4 of each vowel were measured and compared within the twin pairs. Our data seems to point out the importance of a shared environment and the strong influence of learning over the anatomical identity of the monozygotic twins regarding the production of vowels. But, additional results suggest (1) the impact of physiology on the production of a vowel following a velar consonant and (2) the interaction of physiology and stress in inter-speaker variability.  

On the Statistical Significance of one Pair of Monozygotic Twins in Clinical Genetics

1963 ◽  
Vol 12 (4) ◽  
pp. 317-323
Author(s):  
L. Gedda
Keyword(s):  
Twin Pair ◽  
Statistical Significance ◽  
Statistical Treatment ◽  
Monozygotic Twins ◽  
Monozygotic Twin ◽  
Clinical Genetics ◽  
Pair Comparison ◽  
Monozygotic Twin Pair ◽  
Development Result

SUMMARYA case of one twin pair concordant or discordant as to a given disease is always very important for Clinical Genetics, especially when it is monozygotic. In Clinical Genetics, isolated pairs occur to the physician, and the diagnosis must therefore be based on intra-pair comparison. The statistical treatment of the case must consider the fact that a concordant monozygotic twin pair represents a statistical universe rather than a statistical unit. This entails taking into account many traits concerning the time of onset, the symptoms, development, result of treatment, etc. Suggestions are made for the statistical treatment of such cases.

Mental and Motor Development in Monozygotic Co-Twins With Dissimilar Birth Weights

PEDIATRICS ◽  
1974 ◽  
Vol 53 (6) ◽  
pp. 884-889
Author(s):  
Toshio Fujikura ◽  
Luz A. Froehlich
Keyword(s):  
Birth Weight ◽  
Human Brain ◽  
Motor Development ◽  
Monozygotic Twins ◽  
Monozygotic Twin ◽  
Mental Development

Developmental measures in 125 monozygotic twin sets with unequal birth weights between co-twins were studied. There were no significant differences between co-twins in the Bayley Mental and Motor Scores at 8 months nor the Stanford-Binet IQ at 4 years. A reportedly higher IQ for the heavier of monozygotic twins was not confirmed in this study, even among pairs with large birth-weight differences. Although the effects of nutrition on the mental development of the fetus are currently of great concern, these data suggest that the developing human brain seems to have a strong resistance to intrauterine deprivation.

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