Meiosis in mammals: recombination, non-disjunction and the environment

2006 ◽  
Vol 34 (4) ◽  
pp. 574-577 ◽  
Author(s):  
P.A. Hunt
Keyword(s):  
Environmental Factors ◽  
Meiotic Recombination ◽  
Maternal Age ◽  
Control Mechanisms ◽  
Human Female ◽  
Meiotic Process ◽  
A Cell ◽  
Males And Females ◽  
Genetic And Environmental Factors ◽  
Combined Data

By comparison with other species, the meiotic process in the human female is extraordinarily error-prone. In addition to the well-known effect of advancing maternal age, recent studies have demonstrated that the number and location of meiotic recombination events influences the likelihood of meiotic non-disjunction in our species. Although this association extends to many other organisms, the factors that influence the number and placement of exchanges within a cell remain poorly understood. Like other aspects of meiosis, the control of recombination is likely to be subject to variation among species. In this review we summarize data from recent studies in mammals; the combined data suggest that both genetic and environmental factors influence recombination in mammals and, importantly, that control mechanisms probably differ between males and females.

The Heritability of Mortality Due to Heart Diseases: A Correlated Frailty Model Applied to Danish Twins

Twin Research ◽  
2001 ◽  
Vol 4 (4) ◽  
pp. 266-274 ◽  
Author(s):  
Andreas Wienke ◽  
Niels V. Holm ◽  
Axel Skytthe ◽  
Anatoli I. Yashin
Keyword(s):  
Environmental Factors ◽  
Parametric Analysis ◽  
Structural Equation ◽  
Heart Diseases ◽  
Frailty Model ◽  
Equation Model ◽  
Shared Environment ◽  
Males And Females ◽  
Genetic And Environmental Factors

AbstractData of the Danish Twin Registry on monozygotic and dizygotic twins are used to analyse genetic and environmental influences on susceptibility to heart diseases for males and females, respectively. The sample includes 7955 like-sexed twin pairs born between 1870 and 1930. Follow-up was from 1 January 1943 to 31 December 1993 which results in truncation (twin pairs were included in the study if both individuals were still alive at the beginning of the follow-up) and censoring (nearly 40% of the study population was still alive at the end of the follow-up). We use the correlated gamma-frailty model for the genetic analysis of frailty to account for this censoring and truncation. During the follow-up 9370 deaths occurred, 3393 deaths were due to heart diseases in general, including 2476 deaths due to coronary heart disease (CHD). Proportions of variance of frailty attributable to genetic and environmental factors were analyzed using the structural equation model approach. Different standard biometric models are fitted to the data to evaluate the magnitude and nature of genetic and environmental factors on mortality. Using the best fitting model heritability of frailty (liability to death) was found to be 0.55 (0.07) and 0.53 (0.11) with respect to heart diseases and CHD, respectively, for males and 0.52 (0.10) and 0.58 (0.14) for females in a parametric analysis. A semi-parametric analysis shows very similar results. These analyses may indicate the existence of a strong genetic influence on individual frailty associated with mortality caused by heart diseases and CHD in both, males and females. The nature of genetic influences on frailty with respect to heart diseases and CHD is probably additive. No evidence for dominance and shared environment was found.

Genetic and Environmental Overlap Between Substance Use and Delinquency in Adolescence: An Analysis by Same-Sex Twins

2018 ◽  
Vol 17 (2) ◽  
pp. 154-173 ◽  
Author(s):  
Danielle L. Boisvert ◽  
Eric J. Connolly ◽  
Jamie C. Vaske ◽  
Todd A. Armstrong ◽  
Brian B. Boutwell
Keyword(s):  
Substance Use ◽  
Environmental Factors ◽  
Delinquent Behavior ◽  
Adult Health ◽  
Same Sex ◽  
National Longitudinal Study ◽  
Offending Behavior ◽  
Genetic Overlap ◽  
Males And Females ◽  
Genetic And Environmental Factors

During adolescence, many teens begin to experiment with substances and engage in delinquent behavior. The current study seeks to examine whether and to what extent genetic and environmental factors contribute to the association between substance use (i.e., marijuana and alcohol) and different forms of delinquent offending (i.e., violent and nonviolent) across males and females. Analyses were based on same-sex twins ( N = 1,072) from the sibling subsample of the National Longitudinal Study of Adolescent to Adult Health (Add Health). The results revealed moderate to large genetic overlap between substance use and delinquent behavior for males. Much of the covariation between alcohol use and offending behavior for females was attributable to common environmental factors, while common genetic factors explained a large portion of the overlap between marijuana use and offending in males and females. The implications of these findings for sex differences in prevention and intervention efforts are discussed from a biosocial perspective.

The B chromosomes of Locusta migratoria. II. Effects on chiasma frequency

Genome ◽  
1988 ◽  
Vol 30 (2) ◽  
pp. 118-123 ◽  
Author(s):  
Esther Viseras ◽  
F. Javier Salcedo ◽  
Juan Pedro M. Camacho
Keyword(s):  
Environmental Factors ◽  
Genetic Relationship ◽  
Chiasma Frequency ◽  
Locusta Migratoria ◽  
B Chromosomes ◽  
A Cell ◽  
Genetic And Environmental Factors ◽  
Close Genetic Relationship ◽  
Accessory Chromosomes

The effects of accessory chromosomes of Locusta migratoria have been tested at intra- and inter-individual levels. Intraindividual analysis demonstrated that chiasma frequency of a cell is independent of the number of B-chromosomes that it contains. Interindividual analysis was done using males with a close genetic relationship (brother–brother and father–son) as well as males not showing such relationship. This analysis demonstrated the importance of both genetic and environmental factors in determining chiasma frequency. It was concluded that B chromosomes have no influence on this character.Key words: Locusta, B chromosomes, chiasma frequency.

scholarly journals Individual Differences in Personality Masculinity-Femininity: Examining the Effects of Genes, Environment, and Prenatal Hormone Transfer

2016 ◽  
Vol 19 (2) ◽  
pp. 87-96 ◽  
Author(s):  
Karin J. H. Verweij ◽  
Miriam A. Mosing ◽  
Fredrik Ullén ◽  
Guy Madison
Keyword(s):  
Individual Differences ◽  
Environmental Factors ◽  
Big Five Personality ◽  
Same Sex ◽  
Personality Score ◽  
Opposite Sex ◽  
Males And Females ◽  
Genetic And Environmental Factors ◽  
Underlying Mechanisms ◽  
The Individual

Males and females score differently on some personality traits, but the underlying etiology of these differences is not well understood. This study examined genetic, environmental, and prenatal hormonal influences on individual differences in personality masculinity–femininity (M-F). We used Big-Five personality inventory data of 9,520 Swedish twins (aged 27 to 54) to create a bipolar M-F personality scale. Using biometrical twin modeling, we estimated the influence of genetic and environmental factors on individual differences in a M-F personality score. Furthermore, we tested whether prenatal hormone transfer may influence individuals’ M-F scores by comparing the scores of twins with a same-sex versus those with an opposite-sex co-twin. On average, males scored 1.09 standard deviations higher than females on the created M-F scale. Around a third of the variation in M-F personality score was attributable to genetic factors, while family environmental factors had no influence. Males and females from opposite-sex pairs scored significantly more masculine (both approximately 0.1 SD) than those from same-sex pairs. In conclusion, genetic influences explain part of the individual differences in personality M-F, and hormone transfer from the male to the female twin during pregnancy may increase the level of masculinization in females. Additional well-powered studies are needed to clarify this association and determine the underlying mechanisms in both sexes.

scholarly journals Exploring the inter-relationship of smoking age-at-onset, cigarette consumption and smoking persistence: genes or environment?

2007 ◽  
Vol 37 (9) ◽  
pp. 1357-1367 ◽  
Author(s):  
KATHERINE I. MORLEY ◽  
MICHAEL T. LYNSKEY ◽  
PAMELA A. F. MADDEN ◽  
SUSAN A. TRELOAR ◽  
ANDREW C. HEATH ◽  
...  
Keyword(s):  
Sex Differences ◽  
Environmental Factors ◽  
Age At Onset ◽  
Smoking Behaviour ◽  
Cigarette Consumption ◽  
Males And Females ◽  
Genetic And Environmental Factors ◽  
Relationship Of ◽  
Modelling Methods ◽  
Insight Into

ABSTRACTBackgroundWe investigated the genetic and environmental contributions to covariation between smoking age-at-onset, cigarette consumption and smoking persistence.MethodMultivariate biometrical modelling methods were applied to questionnaire data from Australian twins and their siblings (14 472 individuals from 6247 families). The contributions of genetic and environmental factors to covariation between the three traits were estimated, allowing for sex differences in both trait prevalence and the magnitude of genetic and environmental effects.ResultsAll traits were moderately heritable in males and females (estimates between 0·40 and 0·62), but there were sex differences in the extent to which additive genetic influences were shared across traits. Twin-specific environmental factors accounted for a substantial proportion of the variance in smoking age-at-onset in females (0·19) and males (0·12), but had little influence (<0·08) on other traits. Unique environmental factors were estimated to have a moderate influence on smoking age-at-onset (0·17 for females, 0·19 for males), but a stronger influence on other traits (between 0·39 and 0·49).ConclusionsThese results provide some insight into observed sex differences in smoking behaviour, and suggest that searching for pleiotropic genes may prove fruitful. However, further work on phenotypic definitions of smoking behaviour, particularly persistence, is warranted.

Reductionist thinking and animal models in neuropsychiatric research

2019 ◽  
Vol 42 ◽  
Author(s):  
Nicole M. Baran
Keyword(s):  
Animal Models ◽  
Mental Disorders ◽  
Environmental Factors ◽  
Neuropsychiatric Disorders ◽  
Model Organisms ◽  
Developmental Genetic ◽  
Term Study ◽  
Genetic And Environmental Factors ◽  
Mechanisms Of Plasticity

AbstractReductionist thinking in neuroscience is manifest in the widespread use of animal models of neuropsychiatric disorders. Broader investigations of diverse behaviors in non-model organisms and longer-term study of the mechanisms of plasticity will yield fundamental insights into the neurobiological, developmental, genetic, and environmental factors contributing to the “massively multifactorial system networks” which go awry in mental disorders.

The dual nature of obesity in metabolic programming: quantity versus quality of adipose tissue

2020 ◽  
Vol 134 (18) ◽  
pp. 2447-2451
Author(s):  
Anissa Viveiros ◽  
Gavin Y. Oudit
Keyword(s):  
Adipose Tissue ◽  
Environmental Factors ◽  
Maternal Obesity ◽  
Metabolic Programming ◽  
Dual Nature ◽  
Prevalence Of Obesity ◽  
Adipose Tissue Volume ◽  
Males And Females ◽  
Metabolically Healthy

Abstract The global prevalence of obesity has been rising at an alarming rate, accompanied by an increase in both childhood and maternal obesity. The concept of metabolic programming is highly topical, and in this context, describes a predisposition of offspring of obese mothers to the development of obesity independent of environmental factors. Research published in this issue of Clinical Science conducted by Litzenburger and colleagues (Clin. Sci. (Lond.) (2020) 134, 921–939) have identified sex-dependent differences in metabolic programming and identify putative signaling pathways involved in the differential phenotype of adipose tissue between males and females. Delineating the distinction between metabolically healthy and unhealthy obesity is a topic of emerging interest, and the precise nature of adipocytes are key to pathogenesis, independent of adipose tissue volume.

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