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Twin Research and Human Genetics : the... Feb 2024There are sex-dependent differences in hematological and biochemical variables in adulthood attributed to the predominant effects of testosterone in males and estrogen...
There are sex-dependent differences in hematological and biochemical variables in adulthood attributed to the predominant effects of testosterone in males and estrogen in females. The Twin Testosterone Transfer (TTT) hypothesis proposes that opposite-sex females may develop male-typical traits due to exposure to relatively higher levels of prenatal testosterone than same-sex females. Additionally, prenatal testosterone exposure has been suggested as a correlate of current circulating testosterone levels. Consequently, opposite-sex females might exhibit male-typical patterns in their hematological and biochemical variables. Despite this hypothesis, routine laboratory investigations assign the same reference range to all females. Our cross-sectional study, conducted in Tamale from January to September 2022, included 40 twins, comprising 10 opposite-sex (OS) males (25%), 10 OS females (25%), and 20 same-sex (SS) females (50%), all aged between 18 and 27 years. Fasting venous blood samples were collected and analyzed using automated hematology and biochemistry laboratory analyzers. Results indicated that levels of hemoglobin, serum creatinine, gamma-glutamyl transferase, total protein, globulins, and total testosterone were significantly higher in OS males than OS females. Conversely, total cholesterol and low-density lipoprotein cholesterol were significantly higher in OS females than OS males. Unexpectedly, levels of low-density lipoprotein cholesterol and total testosterone were significantly higher in SS females than OS females. Contrary to expectations, opposite-sex females did not exhibit male-typical patterns in their hematological and biochemical variables. This suggests that the TTT effect may not occur or may not be strong enough to markedly affect hematological and biochemical variables in OS females.
Topics: Humans; Female; Male; Adult; Ghana; Testosterone; Cross-Sectional Studies; Adolescent; Twins, Dizygotic; Twins, Monozygotic; Young Adult
PubMed: 38444332
DOI: 10.1017/thg.2024.7 -
Communications Biology Jan 2024The aesthetic values that individuals place on visual images are formed and shaped over a lifetime. However, whether the formation of visual aesthetic value is solely...
The aesthetic values that individuals place on visual images are formed and shaped over a lifetime. However, whether the formation of visual aesthetic value is solely influenced by environmental exposure is still a matter of debate. Here, we considered differences in aesthetic value emerging across three visual domains: abstract images, scenes, and faces. We examined variability in two major dimensions of ordinary aesthetic experiences: taste-typicality and evaluation-bias. We build on two samples from the Australian Twin Registry where 1547 and 1231 monozygotic and dizygotic twins originally rated visual images belonging to the three domains. Genetic influences explained 26% to 41% of the variance in taste-typicality and evaluation-bias. Multivariate analyses showed that genetic effects were partially shared across visual domains. Results indicate that the heritability of major dimensions of aesthetic evaluations is comparable to that of other complex social traits, albeit lower than for other complex cognitive traits. The exception was taste-typicality for abstract images, for which we found only shared and unique environmental influences. Our study reveals that diverse sources of genetic and environmental variation influence the formation of aesthetic value across distinct visual domains and provides improved metrics to assess inter-individual differences in aesthetic value.
Topics: Humans; Australia; Benchmarking; Environmental Exposure; Esthetics; Individuality
PubMed: 38184755
DOI: 10.1038/s42003-023-05710-4 -
Equine Veterinary Journal Jul 2024Transvaginal ultrasound-guided aspiration (TUA) is used for post-fixation twin reduction in mares. However, there is limited information regarding factors that influence...
BACKGROUND
Transvaginal ultrasound-guided aspiration (TUA) is used for post-fixation twin reduction in mares. However, there is limited information regarding factors that influence pregnancy outcome after TUA.
OBJECTIVES
To evaluate the effect of day of gestation on which TUA is performed, aspiration volume, puncture of the conceptus, medication administered before and after TUA, embryo location, mare age and parity and operator experience on pregnancy and foaling rates after TUA.
STUDY DESIGN
Retrospective case series.
METHODS
Data were collected from case records of 464 TUAs performed by 14 operators in 422 mares diagnosed pregnant with dizygotic twins in two different facilities between 2010 and 2019. Pregnancy status was determined by ultrasonography at 5-7 days and 3-4 weeks after the TUA was performed. Subsequent pregnancy and foaling results were obtained by follow-up communication. The effects of mare, gestation- and TUA-related variables on pregnancy and foaling rates were analysed by the chi-square-test for homogeneity and Fisher's exact test and logistic regression.
RESULTS
TUA was performed between 21 and 82 days of gestation in unilaterally (267/359 [74.4%]) and bilaterally fixed (92/359 [25.6%]) twin pregnancies. A singleton pregnancy (218/381 [57.2%]), persistent twin pregnancy (60/381 [15.8%]), or the loss of both conceptuses (103/381 [27%]) was confirmed 5-7 days after TUA was performed. At 3-4 weeks post TUA 50.3% (163/324) of mares were diagnosed with a single viable pregnancy and 40.1% (127/317) went on to deliver a live single foal. TUA performed early in gestation (D 25-35) resulted in the birth of a live singleton foal in 49.3% (74/150) of mares.
MAIN LIMITATIONS
Missing retrospective data despite extensive follow-up.
CONCLUSION
This is the first large scale study to demonstrate that acceptable pregnancy and foaling rates can be achieved in mares diagnosed with twins when TUA is performed early in gestation (<40 days).
Topics: Horses; Pregnancy; Female; Animals; Retrospective Studies; Pregnancy Reduction, Multifetal; Pregnancy Outcome; Ultrasonography, Interventional
PubMed: 38353172
DOI: 10.1111/evj.14071 -
PloS One 2024Alcohol intent (the susceptibility to initiating alcohol use) and alcohol sips (the initiation of alcohol) in youth are a multifactorial puzzle with many components....
INTRODUCTION
Alcohol intent (the susceptibility to initiating alcohol use) and alcohol sips (the initiation of alcohol) in youth are a multifactorial puzzle with many components. This research aims to examine the connection between genetic and environmental factors across sex, race and ethnicity.
METHODS
Data was obtained from the twin hub of the Adolescent Brain Cognitive Development (ABCD) study at baseline (2016-2018). Variance component models were conducted to dissect the additive genetic (A), common (C) and unique environmental (E) effects on alcohol traits. The proportion of the total alcohol phenotypic variation attributable to additive genetic factors is reported as heritability (h2).
RESULTS
The sample (n = 1,772) included an approximately equal male-female distribution. The 886 same-sex twin pairs were 60.4% dizygotic (DZ), 39.6% monozygotic (MZ), 65.4% non-Hispanic Whites, 13.9% non-Hispanic Blacks, 10.8% of Hispanics with a mean age of 121.2 months. Overall, genetic predisposition was moderate for alcohol intent (h2 = 28%, p = .006) and low for alcohol initiation (h2 = 4%, p = 0.83). Hispanics (h2 = 53%, p < .0001) and Blacks (h2 = 48%, p < .0001) demonstrated higher alcohol intent due to additive genetic factors than Whites (h2 = 34%, p < .0001). Common environmental factors explained more variation in alcohol sips in females (c2 = 63%, p = .001) than in males (c2 = 55%, p = .003). Unique environmental factors largely attributed to alcohol intent, while common environmental factors explained the substantial variation in alcohol initiation.
CONCLUSION
Sex and racial/ethnic disparities in genetic and environmental risk factors for susceptibility to alcohol initiation can lead to significant health disparities. Certain populations may be at greater risk for alcohol use due to their genetic and ecological factors at an early age.
Topics: Adolescent; Child; Female; Humans; Male; Alcohol Drinking; Ethnicity; Twins; Racial Groups
PubMed: 38359015
DOI: 10.1371/journal.pone.0298456 -
Journal of Personality Aug 2024This study examined whether phenotypic correlations between psychopathological dimensions and personality traits of different hierarchical levels originate from common...
OBJECTIVE
This study examined whether phenotypic correlations between psychopathological dimensions and personality traits of different hierarchical levels originate from common genetic and environmental sources of variance.
METHOD
Participants were 386 monozygotic and 204 dizygotic twins. The Psychiatric Diagnostic Screening Questionnaire (PDSQ) was applied along with the Revised NEO Personality Inventory (NEO-PI-R). The results of the CFA confirmed the hypothesis of the internalizing and externalizing dimensions underlying PDSQ scales.
RESULTS
The results indicated a significantly greater role of genetic compared to environmental factors in the relationship between internalizing psychopathology and personality traits. Facets of neuroticism showed positive genetic links with internalizing disorders, while negative genetic links were shown for all facets of extraversion except excitement-seeking, competence, self-discipline, achievement striving, actions, and trust. Lower-order personality traits were shown to be associated with internalizing disorders more intensively than the broader domains to which they belong, both at the phenotypic and genetic levels.
CONCLUSIONS
High neuroticism, together with several facets from the domain of extraversion and conscientiousness seems to represent an increased genetic susceptibility to the disorders from the internalizing spectrum. Results also suggest that specific environmental factors which are not shared with personality traits contribute to the internalizing symptoms.
Topics: Humans; Male; Female; Adult; Personality; Mental Disorders; Personality Inventory; Middle Aged; Young Adult; Gene-Environment Interaction; Neuroticism; Phenotype; Twins, Monozygotic; Personality Disorders; Twins, Dizygotic; Extraversion, Psychological
PubMed: 37614221
DOI: 10.1111/jopy.12878 -
Science Immunology Apr 2024Although human twin studies have revealed the combined contribution of heritable and environmental factors in shaping immune system variability in blood, the...
Although human twin studies have revealed the combined contribution of heritable and environmental factors in shaping immune system variability in blood, the contribution of these factors to immune system variability in tissues remains unexplored. The human uterus undergoes constant regeneration and is exposed to distinct environmental factors. To assess uterine immune system variation, we performed a system-level analysis of endometrial and peripheral blood immune cells in monozygotic twins. Although most immune cell phenotypes in peripheral blood showed high genetic heritability, more variation was found in endometrial immune cells, indicating a stronger influence by environmental factors. Cytomegalovirus infection was identified to influence peripheral blood immune cell variability but had limited effect on endometrial immune cells. Instead, hormonal contraception shaped the local endometrial milieu and immune cell composition with minor influence on the systemic immune system. These results highlight that the magnitude of human immune system variation and factors influencing it can be tissue specific.
Topics: Female; Humans; Twins, Dizygotic; Twins, Monozygotic; Endometrium; Uterus; Immune System
PubMed: 38579017
DOI: 10.1126/sciimmunol.adj7168 -
Applied Neuropsychology. Child 2024In 2005, the 3q29 deletion syndrome was identified and defined as a rare chromosomal anomaly that effects approximately one in 30,000-40,000 children. It has a complex...
In 2005, the 3q29 deletion syndrome was identified and defined as a rare chromosomal anomaly that effects approximately one in 30,000-40,000 children. It has a complex neuropsychiatric profile, often resulting in developmental delays, intellectual disabilities, attentional deficits, classic physical traits, and behavioral health disturbances, including social and emotional issues. Rarely has this syndrome been seen and evaluated in fraternal twins, only one of whom has the 3q29 deletion syndrome. This case study highlights Twin 1's strengths and weaknesses and compares her 2020 neuropsychological data, including a comparison of her Reitan-Indiana Neuropsychological Battery (RINB) results to her 2022 profile, which reveals a failure-to-thrive profile.
Topics: Child; Female; Humans; Developmental Disabilities; Chromosome Deletion; Twins, Dizygotic; Chromosome Disorders; Intellectual Disability
PubMed: 37480577
DOI: 10.1080/21622965.2023.2235707 -
Multivariate Behavioral Research Jul 2023One type of genotype-environment interaction occurs when genetic effects on a phenotype are moderated by an environment; or when environmental effects on a phenotype are...
One type of genotype-environment interaction occurs when genetic effects on a phenotype are moderated by an environment; or when environmental effects on a phenotype are moderated by genes. Here we outline these types of genotype-environment interaction models, and propose a test of genotype-environment interaction based on the classical twin design, which includes observed genetic variables (polygenic scores: PGSs) that account for part of the genetic variance of the phenotype. We introduce environment-by-PGS interaction and the results of a simulation study to address statistical power and parameter recovery. Next, we apply the model to empirical data on anxiety and negative affect in children. The power to detect environment-by-PGS interaction depends on the heritability of the phenotype, and the strength of the PGS. The simulation results indicate that under realistic conditions of sample size, heritability and strength of the interaction, the environment-by-PGS model is a viable approach to detect genotype-environment interaction. In 7-year-old children, we defined two PGS based on the largest genetic association studies for 2 traits that are genetically correlated to childhood anxiety and negative affect, namely major depression (MDD) and intelligence (IQ). We find that common environmental influences on negative affect are amplified for children with a lower IQ-PGS.
PubMed: 37439516
DOI: 10.1080/00273171.2023.2228763 -
Journal of Child Psychology and... Feb 2024Children with developmental language disorder (DLD) experience higher levels of peer victimization than their peers. However, it is not known if such associations...
BACKGROUND
Children with developmental language disorder (DLD) experience higher levels of peer victimization than their peers. However, it is not known if such associations reflect genetic and environmental confounding. We used a co-twin control design to investigate the association of language difficulties (DLD and separately poor pragmatic language) with peer victimization and compare the developmental trajectories of peer victimization across adolescence for those with and without language difficulties.
METHODS
Participants were 3,400 pairs of twins in the Twins Early Development Study (TEDS), a UK-based population birth cohort. Language abilities were assessed via online tests at age 11 and peer victimization was self-reported at ages 11, 14 and 16. Language difficulties were defined as language abilities at least -1.25 SD below the mean of the TEDS sample. We performed linear regressions and latent growth curve modeling at a population level and within monozygotic and same-sex dizygotic twin pairs.
RESULTS
At population level, youth with DLD experienced higher levels of peer victimization at ages 11 (β = 0.27, 95% Confidence Interval (CI) 0.20-0.35), 14 (β = 0.15, 95% CI 0.03-0.27) and 16 (β = 0.17, 95% CI 0.03-0.32) and a sharper decline in peer victimization between ages 11 and 16 compared to their peers without DLD. The associations between DLD and peer victimization were reduced in strength and not statistically significant in within-twin models. Moreover, there was no difference in the rate of change in peer victimization between twin pairs discordant for DLD. Results were similar for the association of poor pragmatic language with peer victimization.
CONCLUSIONS
Associations between language difficulties (DLD and separately, poor pragmatic language) and peer victimization were confounded by genetic and shared environmental factors. Identifying specific factors underlying these associations is important for guiding future work to reduce peer victimization among adolescents with language difficulties.
PubMed: 38425078
DOI: 10.1111/jcpp.13969 -
Cancer Epidemiology, Biomarkers &... Feb 2024Cirrus is an automated risk predictor for breast cancer that comprises texture-based mammographic features and is mostly independent of mammographic density. We...
BACKGROUND
Cirrus is an automated risk predictor for breast cancer that comprises texture-based mammographic features and is mostly independent of mammographic density. We investigated genetic and environmental variance of variation in Cirrus.
METHODS
We measured Cirrus for 3,195 breast cancer-free participants, including 527 pairs of monozygotic (MZ) twins, 271 pairs of dizygotic (DZ) twins, and 1,599 siblings of twins. Multivariate normal models were used to estimate the variance and familial correlations of age-adjusted Cirrus as a function of age. The classic twin model was expanded to allow the shared environment effects to differ by zygosity. The SNP-based heritability was estimated for a subset of 2,356 participants.
RESULTS
There was no evidence that the variance or familial correlations depended on age. The familial correlations were 0.52 (SE, 0.03) for MZ pairs and 0.16(SE, 0.03) for DZ and non-twin sister pairs combined. Shared environmental factors specific to MZ pairs accounted for 20% of the variance. Additive genetic factors accounted for 32% (SE = 5%) of the variance, consistent with the SNP-based heritability of 36% (SE = 16%).
CONCLUSION
Cirrus is substantially familial due to genetic factors and an influence of shared environmental factors that was evident for MZ twin pairs only. The latter could be due to nongenetic factors operating in utero or in early life that are shared by MZ twins.
IMPACT
Early-life factors, shared more by MZ pairs than DZ/non-twin sister pairs, could play a role in the variation in Cirrus, consistent with early life being recognized as a critical window of vulnerability to breast carcinogens.
Topics: Female; Humans; Breast; Breast Neoplasms; Mammography; Risk Factors; Twins, Dizygotic; Twins, Monozygotic
PubMed: 38059829
DOI: 10.1158/1055-9965.EPI-23-1012