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Additive Genes (additive + gene)
Selected AbstractsBody dissatisfaction and drive for thinness in young adult twinsINTERNATIONAL JOURNAL OF EATING DISORDERS, Issue 3 2005Anna Keski-Rahkonen MD Abstract Objective We explored correlates of the Eating Disorder Inventory subscales Body Dissatisfaction (BD) and Drive for Thinness (DT) and genetic and environmental influences on these traits. Method In a population-based sample of 4,667 Finnish twins aged 22,27 years, we conducted twin modeling to explore genetic and environmental contributions to body dissatisfaction and drive for thinness. Logistic regression was used for the correlational analysis. Results Various eating and body size-related factors and psychosomatic symptoms were significantly associated with high body dissatisfaction and drive for thinness in both genders. In women, early puberty onset, early initiation of sexual activity, and multiple sex partners were statistically significant risk factors of body dissatisfaction. In gender-specific univariate twin models, additive genes accounted for 59.4% (95% confidence interval [CI] = 53.2,64.7%) of the variance in body dissatisfaction and for 51.0% (95% CI = 43.7,57.5%) of the variance in drive for thinness among females, but for none of the variance among males. Discussion There are very distinct gender differences in the heritability patterns of body dissatisfaction and drive for thinness in young adults. © 2005 by Wiley Periodicals, Inc. [source] A quantitative genetic study of cephalometric variables in twinsORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 3 2001C. Carels This study aimed at determining the relative genetic and environmental impact on a number of well-known cephalometric variables in twins. In order to find a clue in the heritability pattern of some dentofacial characteristics and on the expected limits of the therapeutic impact on the dentofacial subparts they are representing. Cephalograms were collected from 33 monozygotic and 46 dizygotic twins, who did not undergo any orthodontic treatment. Nineteen linear and four angular variables were selected all representing a different definite subpart of the dentofacial complex. The reproducibility of the measurement of most of the linear variables was very high. A genetic analysis using model fitting and path analysis was carried out. First, data were checked on the fulfilment of the conditions for genetic analysis in twins reared together. The results show that the genetic determination is significantly higher for vertical (72%) than for horizontal (61%) variables. As far as the genetic component is concerned, all variables selected seem to be inherited by additive genes, except for mandibular body length, which was determined by dominant alleles. Sex differences in genetic determination were found for the anterior face height, showing a significantly higher genetic component for boys (91%) than for girls (68%). For the angular measurements, no genetic influence was found: only environmental influences common to both members of each pair could be demonstrated. [source] Error rate on the antisaccade task: Heritability and developmental change in performance among preadolescent and late-adolescent female twin youthPSYCHOPHYSIOLOGY, Issue 5 2002Stephen M. Malone We examined heritability of error rate on the antisaccade task among female twin youths. This task appears to be sensitive to prefrontal functioning, providing a measure of individual differences in inhibitory control associated with genetic risk for schizophrenia. The sample consisted of 674 11-year-olds and 616 17-year-olds, comprising the two cohorts of female twins from the Minnesota Twin Family Study, a population-based investigation of substance abuse and related psychopathology. We used biometric model-fitting methods to determine the relative magnitude of genetic and environmental influences on performance. In both age cohorts, the best fitting model contained additive genes and nonshared environment. Despite substantial age-related differences in mean performance levels (effect size = .81), additive genes accounted for greater than half the variance in performance in both age cohorts. These results are consistent with the hypothesis that antisaccade error rate might serve as an endophenotype for behavior disorders reflecting frontal lobe dysfunction or problems with inhibitory control. [source] Bladder neck mobility is a heritable traitBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 3 2005H.P. Dietz Objective Congenital connective tissue dysfunction may partly be responsible for female pelvic organ prolapse and urinary incontinence. We undertook a heritability study to determine whether mobility of the bladder neck, one of the main determinants of stress urinary incontinence, is genetically influenced. Design Heritability study using a twin model and structural equation modelling. Setting Queensland Institute of Medical Research, Brisbane, Australia. Population One hundred and seventy-eight nulliparous Caucasian female twins and their sisters (46 monozygotic pairs, 24 dizygotic pairs and 38 sisters) aged 18,24 years. Methods We performed translabial ultrasound, supine and after bladder emptying, for pelvic organ mobility. Urethral rotation and bladder neck descent were calculated using the best of three effective Valsalva manoeuvres. Main outcome measures Bladder and urethral mobility on Valsalva assessed by urethral rotation, vertical and oblique bladder neck descent. Results Genetic modelling indicated that additive genes accounted for up to 59% of the variance for bladder neck descent. All remaining variance appeared due to environmental influences unique to the individual, including measurement error. Conclusion A significant genetic contribution to the phenotype of bladder neck mobility appears likely. [source] | |||||||||||||