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PloS One 2018Political participation (POP), social participation (SOP), and political interest (PI) are important indicators of social status and social inequality. Previous studies...
Political participation (POP), social participation (SOP), and political interest (PI) are important indicators of social status and social inequality. Previous studies on related trait differences yielded genetic and environmental contributions. However, focusing on adult samples, classical twin designs, and convenience samples often restricts parameter estimation and generalizability, and limits the understanding of age differences. We investigated sources of variance in POP, SOP, and PI in late adolescence and early adulthood with an extended twin family design (ETFD). We analyzed data from over 2,000 representative German twin families. Individual environments not shared by family members reflected the major source of variance for all variables, but genetic influences were also pronounced. Genetic effects were mostly higher for young adults, whereas effects of twins' shared environment were significant in adolescence. Our study deepens the understanding of the interplay between genetic and environmental factors in shaping differences in young persons' integration in society.
Topics: Adolescent; Adult; Female; Gene-Environment Interaction; Germany; Humans; Male; Political Activism; Politics; Social Environment; Twins, Dizygotic; Twins, Monozygotic; Young Adult
PubMed: 30142159
DOI: 10.1371/journal.pone.0202518 -
Fertility and Sterility Feb 2003To report the first conception and delivery following transfer of thawed human blastocysts maintained in extended in vitro culture with cryopreservation at day 6 and 7.
OBJECTIVE
To report the first conception and delivery following transfer of thawed human blastocysts maintained in extended in vitro culture with cryopreservation at day 6 and 7.
DESIGN
Case report.
SETTING
Major urban infertility referral center.
PATIENT(S)
A 26-year-old woman with pelvic endometriosis and two prior unsuccessful in vitro fertilization/embryo transfer (IVF-ET) attempts.
INTERVENTION(S)
The patient underwent controlled ovarian hyperstimulation using a combined FSH + hMG protocol, and 24 oocytes were retrieved.
MAIN OUTCOME MEASURE(S)
Dizygotic twin delivery after IVF and intracytoplasmic sperm injection (ICSI), assisted embryo hatching, and ultrasound-guided transfer of cryopreserved blastocysts.
RESULT(S)
After three embryos were subjected to assisted hatching, they were transferred fresh on day 3, but no implantation occurred. All nontransferred embryos (n = 11) were observed during extended in vitro culture and three blastocysts were selected for cryopreservation on day 6 and 7; thaw and transfer occurred the following month and a pregnancy was achieved. Dizygotic twins (female/female) were delivered by cesarean in the early third trimester.
CONCLUSION(S)
Substantial advancements have been made in the field of embryo cryogenics and in vitro fertilization, but controversy remains regarding the value of freezing late-developing human blastocysts. Here we describe the first reported live births with IVF after extended in vitro culture and cryopreservation at day 6 and 7 after fertilization.
Topics: Adult; Blastocyst; Cryopreservation; Delivery, Obstetric; Embryo Transfer; Female; Fertilization in Vitro; Humans; Infant, Newborn; Pregnancy; Sperm Injections, Intracytoplasmic; Twins, Dizygotic
PubMed: 12568858
DOI: 10.1016/s0015-0282(02)04687-3 -
Mutagenesis Nov 2011The primary aim of this study was to quantify genetic and environmental influences on the frequency of spontaneously occurring micronuclei in children and adults. To...
The primary aim of this study was to quantify genetic and environmental influences on the frequency of spontaneously occurring micronuclei in children and adults. To meet this aim, a total of 63 male and female twin pairs and 19 singletons (145 individuals) were evaluated, ranging in age from 7 to 85 years. Micronuclei frequencies significantly increased with age for both genders (r = 0.49, P < 0.001), with the lowest and highest rates being seen in the 7- to 9 (mean = 0.56%, SD = .28) and 60- to 69-year-olds (mean = 2.12%, SD = 1.0), respectively. This age effect was significantly more pronounced in females than males (P = 0.017). In addition to the main effect of age, the completion of puberty in either gender (P = 0.036) and menopause in females (P = 0.024) was associated with a significant increase in micronuclei frequencies. Genetic model fitting indicated that influences from both additive genetic (65.2% of variance) and unique environmental (34.8% of variance) sources best explained the observed micronuclei frequencies in monozygotic and dizygotic twin pairs. Self-reported health conditions associated with an increased frequency of micronuclei included a history of allergies (P < 0.007) and migraines (P = 0.026). Multivitamin use was also associated with increased micronuclei frequencies (P = 0.004). In contrast, significantly lower micronuclei frequencies were associated with arthritis (P = 0.002), as well as consuming fruit (P = 0.014), green, leafy vegetables (P < 0.001) and/or folate-enriched bread (P = 0.035). A sex-specific effect, resulting in a significantly increased frequency of micronuclei with tobacco usage, was observed for females (but not males). Gender differences also moderated the impact of vitamin D and calcium consumption. In conclusion, the frequency of spontaneously arising micronuclei in humans is a complex trait, being influenced by both heritable genetic and environmental components. Recognition of factors contributing to baseline levels of micronuclei should provide guidance to researchers in designing studies to evaluate agents hypothesised to influence chromosomal instability.
Topics: Adolescent; Adult; Age Distribution; Aged; Child; Female; Gene-Environment Interaction; Health; Humans; Male; Micronuclei, Chromosome-Defective; Middle Aged; Models, Genetic; Regression Analysis; Surveys and Questionnaires; Twins; Twins, Dizygotic; Twins, Monozygotic; Young Adult
PubMed: 21765037
DOI: 10.1093/mutage/ger042 -
Human Reproduction (Oxford, England) Jul 2020Does having a male co-twin influence the female twin's reproductive outcomes?
STUDY QUESTION
Does having a male co-twin influence the female twin's reproductive outcomes?
SUMMARY ANSWER
Women with a male co-twin had the same chances of being pregnant and having children compared to same-sex twin pairs.
WHAT IS KNOWN ALREADY
According to the twin testosterone transfer (TTT) hypothesis, in an opposite-sex twin pregnancy, testosterone transfer from the male to the female co-twin occurs. A large body of literature supports the negative impact of prenatal testosterone exposure on female's reproductive health in animal models; however, evidence from human studies remains controversial.
STUDY DESIGN, SIZE, DURATION
This cohort study included all dizygotic female twins in the Aberdeen Maternity and Neonatal Databank (Scotland) born before 1 January 1979. The 317 eligible women were followed up for 40 years for any pregnancies and the outcome of those pregnancies recorded in the same database.
PARTICIPANTS/MATERIALS, SETTING, METHODS
Fertility outcomes (number of pregnancies, number of livebirths and age at first pregnancy) were compared between women with a male co-twin (exposed group, n = 151) and those with a female co-twin (unexposed group, n = 166). Population averaged models were used to estimate odds ratios (OR) and 95% CI for all outcomes with adjusting for potential confounders.
MAIN RESULTS AND THE ROLE OF CHANCE
There were no differences in chances of having pregnancies (adj. OR 1.33; 95% CI 0.72, 2.45) and livebirths (adj. OR 1.22; 95% CI 0.68, 2.18) between women from same-sex and opposite-sex twin pairs. Women with a male co-twin were more likely to smoke during pregnancy and, in the unadjusted model, were younger at their first pregnancy (OR 2.13; 95% CI 1.21, 3.75). After adjusting for confounding variables (year of birth and smoking status) the latter finding was no longer significant (OR 1.67; 95% CI 0.90, 3.20).
LIMITATIONS, REASONS FOR CAUTION
The dataset was relatively small. For women without a pregnancy recorded in the databank, we assumed that they had not been pregnant.
WIDER IMPLICATIONS OF THE FINDINGS
Despite the evidence from animal studies concerning the adverse effects of prenatal testosterone exposure on female health, our results do not support the TTT hypothesis. The finding that women with a male co-twin are more likely to smoke during pregnancy highlights the importance of considering post-socialisation and social effects in twin studies.
STUDY FUNDING/COMPETING INTEREST(S)
European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie project PROTECTED (grant agreement No. 722634) and FREIA project (grant agreement No. 825100). No competing interests.
TRIAL REGISTRATION NUMBER
N/A.
Topics: Child; Cohort Studies; Female; Humans; Male; Pregnancy; Pregnancy, Twin; Scotland; Testosterone; Twins, Dizygotic
PubMed: 32558884
DOI: 10.1093/humrep/deaa091 -
BMC Oral Health Oct 2020DNA base identification is a proper and high specificity method. However, identification could be challenged in a situation where there is no database or the DNA...
BACKGROUND
DNA base identification is a proper and high specificity method. However, identification could be challenged in a situation where there is no database or the DNA sequence is almost identical, as in the case of monozygotic (MZ) twins. The aim of this study was to introduce a novel forensic method for distinguishing between almost identical MZ twins by means of an intraoral scanner using the 3D digital pattern of the human palate.
METHODS
The palatal area of 64 MZ twins and 33 same-sex dizygotic (DZ) twins (DZSS) and seven opposite-sex dizygotic twins (DZOS) were scanned three times with an intraoral scanner. From the scanned data, an STL file was created and exported into the GOM Inspect® inspection software. All scans within a twin pair were superimposed on each other. The average deviation between scans of the same subject (intra-subject deviation, ISD) and between scans of the two siblings within a twin pair (intra-twin deviation, ITD) was measured. One-sided tolerance interval covering 99% of the population with 99% confidence was calculated for the ISD (upper limit) and the ITD (lower limit).
RESULTS
The mean ISD of the palatal scan was 35.3 μm ± 0.78 μm. The calculated upper tolerance limit was 95 μm. The mean ITD of MZ twins (406 μm ± 15 μm) was significantly (p < 0.001) higher than the ISD, and it was significantly lower than the ITD of DZSS twins (594 μm ± 53 μm, p < 0.01) and the ITD of DZOS twins (853 μm ± 202 μm, p < 0.05).
CONCLUSION
The reproducibility of palatal intraoral scans proved to be excellent. The morphology of the palate shows differences between members of MZ twins despite their almost identical DNA, indicating that this method could be useful in forensic odontology.
Topics: Humans; Palate; Reproducibility of Results; Software; Twins, Dizygotic; Twins, Monozygotic
PubMed: 33008463
DOI: 10.1186/s12903-020-01261-w -
Twin Research and Human Genetics : the... Dec 2018The aim of this study was to examine the effects of genetic and environment influences and sex on injury involvement using two sets of Finnish twin data. The younger...
The aim of this study was to examine the effects of genetic and environment influences and sex on injury involvement using two sets of Finnish twin data. The younger participants were 955 twins born between 1983 and 1987, aged 20 to 24 years. The older participants were 12,428 twins born between 1930 and 1957, aged 33 to 60 years. Within-twin correlations in monozygotic and dizygotic twins suggested that genetic effects play no role in injury involvement among young twins, but do have some effect at older ages. The results indicated that environmental factors have greater importance in injury involvement than genetic factors in the younger twin data set (FT12), whereas in a middle-aged (33-60 years) twin data set, genetic effects explained about quarter of the variance in injury involvement. Sex was a strong contributing factor, with males being generally more prone to injuries than females.
Topics: Adolescent; Adult; Age Factors; Diseases in Twins; Environment; Female; Finland; Humans; Longitudinal Studies; Male; Middle Aged; Registries; Risk Factors; Sex Factors; Twins, Dizygotic; Twins, Monozygotic; Wounds and Injuries; Young Adult
PubMed: 30428952
DOI: 10.1017/thg.2018.61 -
Scientific Reports Aug 2023Previous studies on brain connectivity correlates of autism have often focused on selective connections and yielded inconsistent results. By applying global fiber...
Previous studies on brain connectivity correlates of autism have often focused on selective connections and yielded inconsistent results. By applying global fiber tracking and utilizing a within-twin pair design, we aimed to contribute to a more unbiased picture of white matter connectivity in association with clinical autism and autistic traits. Eighty-seven twin pairs (n = 174; 55% monozygotic; 24 with clinical autism) underwent diffusion tensor imaging. Linear regressions assessed within-twin pair associations between structural brain connectivity of anatomically defined brain regions and both clinical autism and autistic traits. These were explicitly adjusted for IQ, other neurodevelopmental/psychiatric conditions and multiple testing, and implicitly for biological sex, age, and all genetic and environmental factors shared by twins. Both clinical autism and autistic traits were associated with reductions in structural connectivity. Twins fulfilling diagnostic criteria for clinical autism had decreased brainstem-cuneus connectivity compared to their co-twins without clinical autism. Further, twins with higher autistic traits had decreased connectivity of the left hippocampus with the left fusiform and parahippocampal areas. These associations were also significant in dizygotic twins alone. Reduced brainstem-cuneus connectivity might point towards alterations in low-level visual processing in clinical autism while higher autistic traits seemed to be more associated with reduced connectivity in networks involving the hippocampus and the fusiform gyrus, crucial especially for processing of faces and other (higher order) visual processing. The observed associations were likely influenced by both genes and environment.
Topics: Child; Humans; Autism Spectrum Disorder; Autistic Disorder; Brain; Child Development Disorders, Pervasive; Diffusion Tensor Imaging; Twins, Dizygotic; Twins, Monozygotic
PubMed: 37573391
DOI: 10.1038/s41598-023-39876-y -
Twin Research and Human Genetics : the... Feb 2019This study uses novel approaches to examine genetic and environmental influences shared between childhood behavioral inhibition (BI) and symptoms of preadolescent...
This study uses novel approaches to examine genetic and environmental influences shared between childhood behavioral inhibition (BI) and symptoms of preadolescent anxiety disorders. Three hundred and fifty-two twin pairs aged 9-13 and their mothers completed questionnaires about BI and anxiety symptoms. Biometrical twin modeling, including a direction-of-causation design, investigated genetic and environmental risk factors shared between BI and social, generalized, panic and separation anxiety. Social anxiety shared the greatest proportion of genetic (20%) and environmental (16%) variance with BI with tentative evidence for causality. Etiological factors underlying BI explained little of the risk associated with the other anxiety domains. Findings further clarify etiologic pathways between BI and anxiety disorder domains in children.
Topics: Adolescent; Anxiety Disorders; Child; Female; Gene-Environment Interaction; Humans; Inhibition, Psychological; Male; Surveys and Questionnaires; Twins, Dizygotic; Twins, Monozygotic
PubMed: 30698127
DOI: 10.1017/thg.2018.73 -
Archives of Disease in Childhood. Fetal... May 1999To quantify the level of risk for stillbirth and infant death in singleton compared with twin pregnancies, using national data; to determine the independent effects of...
AIM
To quantify the level of risk for stillbirth and infant death in singleton compared with twin pregnancies, using national data; to determine the independent effects of zygosity, sex, and birthweight on these risks in twin pregnancies.
METHODS
A retrospective national study was carried out of all singleton and twin birth and death registrations in England and Wales 1982-91, according to sex and birthweight group. Weinberg's rule was applied to the twin pairs to differentiate mono- from dizygotic twins. Relative risks for mono- compared with dizygous twins for both twins being stillbirths and for one of the pair being a stillbirth were determined. For twins where one was stillborn and the other live born, the relative risk of neonatal and infant mortality in the surviving co-twin was determined.
RESULTS
There were 6 563 834 registered singletons and 70772 registered twin pairs for the period under study. Monozygotic twins had a relative risk of: 18.91 (95% CI 12.48-28.64) for both twins being stillborn; 1.63 (95% CI 1.48-1.79) for one twin being a stillbirth; and 2.26 (95% CI 1.45-3.52) for the live born co-twin dying as a neonate. When both twins were live born and among singletons, the odds ratio for neonatal mortality of being male was 1.41 (95% CI 1.37-1.45) and there was a highly significant negative association with birthweight. After adjusting for birthweight group and sex, twins had a reduced neonatal mortality compared with singletons: odds ratio 0.91 (95% CI 0.85-0.96).
CONCLUSIONS
Fetal death in one of monozygotic twins has serious implications for survival of the co-twin. Monochorionicity is probably the essential feature of the increased risk to the co-twin. It is imperative that all fetal deaths in multiple pregnancies are recorded and chorionicity determined if parents are to be adequately counselled.
Topics: Birth Weight; England; Female; Fetal Death; Humans; Infant Mortality; Infant, Newborn; Male; Odds Ratio; Risk Factors; Sex Factors; Twins, Dizygotic; Twins, Monozygotic; Wales
PubMed: 10212085
DOI: 10.1136/fn.80.3.f217 -
Twin Research and Human Genetics : the... Feb 2009The classical twin design uses data on the variation of and covariation between monozygotic and dizygotic twins to infer underlying genetic and environmental causes of... (Review)
Review
The classical twin design uses data on the variation of and covariation between monozygotic and dizygotic twins to infer underlying genetic and environmental causes of phenotypic variation in the population. By using data from additional relative classes, such as parents, extended twin family designs more comprehensively describe the causes of phenotypic variation. This article introduces an extension of previous extended twin family models, the Cascade model, which uses information on twins as well as their siblings, spouses, parents, and children to differentiate two genetic and six environmental sources of phenotypic variation. The Cascade also relaxes assumptions regarding mating and cultural transmission that existed in previous extended twin family designs. The estimation of additional parameters and relaxation of assumptions is potentially important, not only because it allows more fine-grained descriptions of the causes of phenotypic variation, but more importantly, because it can reduce the biases in parameter estimates that exist in earlier designs.
Topics: Environment; Family; Female; Humans; Male; Models, Genetic; Phenotype; Twins, Dizygotic; Twins, Monozygotic
PubMed: 19210175
DOI: 10.1375/twin.12.1.8