Twin Research And Human Genetics[JOURNAL]
Sun
200 papers
THG volume 28 issue 1 Cover.
Twin Res Hum Genet · 2025 Feb · PMID 42253030 · Publisher ↗
Abstract loading — click title to view on PubMed.
Report of the 19th International Congress on Twin Studies, 26-28 September 2024, Assisi, Italy.
Craig JM, Segal N, Tarnoki AD … +1 more , Tarnoki DL
Twin Res Hum Genet · 2025 Feb · PMID 39881603 · Publisher ↗
The International Society for Twin Studies (ISTS) held its 19th scientific congress in Assisi, Italy, from September 26 to 28, 2024. This prestigious event, which was the seventh joint meeting with the World Congress on...
The International Society for Twin Studies (ISTS) held its 19th scientific congress in Assisi, Italy, from September 26 to 28, 2024. This prestigious event, which was the seventh joint meeting with the World Congress on Twin Pregnancy, brought together researchers from various fields, including psychology, biology and medicine. Representatives from ICOMBO (the International Consortium of Multiple Birth Organisations), which supports multiple-birth families worldwide, were also in attendance. Many twin researchers consider this event to be the highlight of their professional year, as it brings together experts and parents alike to discuss the latest advancements in twin studies.
Directional Selection and Evolution of Polygenic Traits in Eastern Eurasia: Insights from Ancient DNA.
Piffer D
Twin Res Hum Genet · 2025 Feb · PMID 39881595 · Publisher ↗
This study explores directional selection on physical and psychosocial phenotypes in Eastern Eurasian populations, utilizing a dataset of 1245 ancient genomes. By analyzing polygenic scores (PGS) for traits including hei...
This study explores directional selection on physical and psychosocial phenotypes in Eastern Eurasian populations, utilizing a dataset of 1245 ancient genomes. By analyzing polygenic scores (PGS) for traits including height, educational attainment (EA), IQ, autism, schizophrenia, and others, we observed significant temporal trends spanning the Holocene era. The results suggest positive selection for cognitive-related traits such as IQ, EA and autism spectrum disorder (ASD), alongside negative selection for anxiety and depression. The results for height were mixed and showed nonlinear relationships with Years Before Present (BP). These trends were partially mediated by genetic components linked to distinct ancestral populations. Regression models incorporating admixture, geography, and temporal variables were used to account for biases in population composition over time. Latitude showed a positive effect on ASD PGS, EA and height, while it had a negative effect on skin pigmentation scores. Additionally, latitude exhibited significant nonlinear effects on multiple phenotypes. The observed patterns highlight the influence of climate-mediated selection pressures on trait evolution. Spline regression revealed that several polygenic scores had nonlinear relationships with years BP. The findings provide evidence for complex evolutionary dynamics, with distinct selective pressures shaping phenotypic diversity across different timescales and environments.
Artificial Intelligence in Predicting Postpartum Hemorrhage in Twin Pregnancies Undergoing Cesarean Section.
Dogru S, Ezveci H, Akkus F … +3 more , Bahçeci P, Karanfil Yaman F, Acar A
Twin Res Hum Genet · 2025 Feb · PMID 39810500 · Publisher ↗
This study aimed to create a risk prediction model with artificial intelligence (AI) to identify patients at higher risk of postpartum hemorrhage using perinatal characteristics that may be associated with later postpart...
This study aimed to create a risk prediction model with artificial intelligence (AI) to identify patients at higher risk of postpartum hemorrhage using perinatal characteristics that may be associated with later postpartum hemorrhage (PPH) in twin pregnancies that underwent cesarean section. The study was planned as a retrospective cohort study at University Hospital. All twin cesarean deliveries were categorized into two groups: those with and without PPH. Using the perinatal characteristics of the cases, four different machine learning classifiers were created: Logistic regression (LR), support vector machine (SVM), random forest (RF), and multilayer perceptron (MLP). LR, RF, and SVM models were created a second time by including class weights to manage the underlying imbalances in the data. A total of 615 twin pregnancies were included in the study. There were 150 twin pregnancies with PPH and 465 without PPH. Dichorionity, PAS, and placenta previa were significantly higher in the PPH-positive group ( = .045, = .004, = .001 respectively). In our model, LR with class weight was the best model with the highest negative predictive value. The AUC in our LR with class weight model was %75.12 with an accuracy of 70.73%, a PPV of 47.92%, and an NPV of 85.33% in our data. Although the application of machine learning to create predictive models using clinical risk factors and our model's 70% accuracy rate are encouraging, it is not sufficient. Machine learning modeling needs further study and validation before being incorporated into clinical use.
The Mechanisms Underlying the Intergenerational Transmission of Substance Use and Misuse: An Integrated Research Approach.
Luo M, Trindade Pons V, Thomas NS … +5 more , Drake J, Su MH, Vladimirov V, van Loo HM, Gillespie NA
Twin Res Hum Genet · 2024 Dec · PMID 39710930 · Publisher ↗
Substance use and substance use disorders run in families. While it has long been recognized that the etiology of substance use behaviors and disorders involves a combination of genetic and environmental factors, two key...
Substance use and substance use disorders run in families. While it has long been recognized that the etiology of substance use behaviors and disorders involves a combination of genetic and environmental factors, two key questions remain largely unanswered: (1) the intergenerational transmission through which these genetic predispositions are passed from parents to children, and (2) the molecular mechanisms linking genetic variants to substance use behaviors and disorders. This article aims to provide a comprehensive conceptual framework and methodological approach for investigating the intergenerational transmission of substance use behaviors and disorders, by integrating genetic nurture analysis, gene expression imputation, and weighted gene co-expression network analysis. We also additionally describe two longitudinal cohorts - the Brisbane Longitudinal Twin Study in Australia and the Lifelines Cohort Study in the Netherlands. By applying the methodological framework to these two unique datasets, our future research will explore the complex interplay between genetic factors, gene expression, and environmental influences on substance use behaviors and disorders across different life stages and populations.
Tribute to Dr Milton Diamond: Twin Studies of Transsexuality/Twin Research Reviews: Loss of a Twin Brother (Recent Memoir); Oxytocin Adminstration During Twin Delivery; Models of Monochorionic Twinning; Twins' Brain Responses to Watching Films/Human Interest: Oldest Conjoined Twins Pass Away; Twins Discordant for Child Abuse; Twins Married to Twins; Rare Quadruplet Set Delivered; Questions of Coincidence; Reared-Apart Twin Valedictorians.
Segal NL
Twin Res Hum Genet · 2024 Aug · PMID 39704314 · Publisher ↗
A tribute to the life and career of Dr Milton Diamond, a leading figure in twin studies of transsexuality and gender identity, is presented. Dr Diamond is famous for revealing the truth about the unsuccessful effort to c...
A tribute to the life and career of Dr Milton Diamond, a leading figure in twin studies of transsexuality and gender identity, is presented. Dr Diamond is famous for revealing the truth about the unsuccessful effort to change a monozygotic male Canadian twin into a female, following accidental ablation of his penis during circumcision. A short summary of recent twin research on human sexuality and transsexuality, focused on Dr Diamond's contributions, is then presented. The tribute and overview are followed by research reviews involving the loss of a twin brother; oxytocin adminstration during twin delivery; models of monochorionic twinning; and twins' brain responses to watching films. The final section of this article covers topics of human interest, including the passing of the world's oldest conjoined twins; twins discordant for child abuse; twins married to twins; the delivery of a rare quadruplet set; questions of coincidence; and reared-apart twin valedictorians.
THG volume 27 issue 4-5 Cover.
Twin Res Hum Genet · 2024 Aug · PMID 39704313 · Publisher ↗
Abstract loading — click title to view on PubMed.
Recollections and Reflections on the Reimer Twin Case in Canada: Interview with Dr H. Keith Sigmundson/Tribute and Twin Research Review: Remembering John L. Hopper; Nonhuman Primate Twinning/Human Interest: film; Different Looking Identical Twin Newborns.
Segal NL
Twin Res Hum Genet · 2024 Dec · PMID 39702945 · Publisher ↗
Dr H. Keith Sigmundson co-authored a seminal article (with the late Dr Milton Diamond) that revealed the truth about a highly controversial twin case. Specifically, the genitals of an infant male monozygotic twin were ac...
Dr H. Keith Sigmundson co-authored a seminal article (with the late Dr Milton Diamond) that revealed the truth about a highly controversial twin case. Specifically, the genitals of an infant male monozygotic twin were accidentally destroyed during a medical procedure performed to alleviate his difficult urination. The child's parents were advised to physically and psychologically transform their twin son into a girl. Occasional reports about the case indicated that the plan was successful, but some members of the medical community were doubtful. An interview with Dr H. Keith Sigmundson, for the purpose of obtaining his unique perspective on this case, is presented. The interview is followed by a tribute to our late twin research colleague, Dr John L. Hopper, of Melbourne, Australia. A review of research on nonhuman primate twinning, an overview of a 2024 documentary film, , and a story of different looking identical twin newborns are also provided.
Late Age at First Birth is a Protective Factor for Preterm Labor and Delivery: The Evidence From the Genetic Study.
Zou J, Li C, Wu H … +3 more , Xue A, Yan L, Zhang Y
Twin Res Hum Genet · 2024 Dec · PMID 39676580 · Publisher ↗
The objective of this study was to investigate the genetic link between the age at first birth (AFB) and the occurrence of preterm labor and delivery, utilizing Mendelian randomization (MR) data alongside genomewide asso...
The objective of this study was to investigate the genetic link between the age at first birth (AFB) and the occurrence of preterm labor and delivery, utilizing Mendelian randomization (MR) data alongside genomewide association analysis (GWAS). We obtained AFB-related GWAS summary data from the European Bioinformatics Institute database and preterm labor and delivery data was sourced from the FinnGen Consortium. The study considered AFB as exposure variables, with the incidence of preterm labor and delivery serving as the outcome variable. Several MR analysis methods, such as inverse-variance weighted (IVW), MR Egger, weighted median, simple, and weighted mode were utilized. Besides MR-Egger intercepts, Cochrane's Q test evaluated heterogeneity in the MR data, while MR-PRESSO test checked for horizontal pleiotropy. To assess the association's sensitivity, A leave-one-out approach was utilized to evaluate the sensitivity of the association. The IVW analysis validated that AFB is an independent risk factor for preterm labor and delivery ( < .001). Horizontal pleiotropy was unlikely to bias causality ( > .05). The likelihood of horizontal pleiotropy affecting causality was low ( > .05), and there was no indication of heterogeneity among the genetic variants ( > .05). Ultimately, a leave-one-out analysis confirmed the stability and reliability of this correlation. Our research indicated that AFB is a protective factor for preterm labor and delivery. Further research is required to clarify the possible mechanisms.
Risk Factor for Child Maltreatment at 3 Years of Age in Japanese Multiples and Singletons: A Population-Based Study.
Yokoyama Y, Ogata Y, Silventoinen K
Twin Res Hum Genet · 2024 Dec · PMID 39639461 · Publisher ↗
We evaluated the prevalence and risk factors for child maltreatment in multiples aged 3 years and compared them to singletons in Japanese population-based data. Records on child maltreatment and health check-ups at 3 yea...
We evaluated the prevalence and risk factors for child maltreatment in multiples aged 3 years and compared them to singletons in Japanese population-based data. Records on child maltreatment and health check-ups at 3 years of age from 17,125 singletons, 488 twins and 18 triplets were collected from a Public Health Center between April 2007 and March 2011. The associations of child maltreatment with potential risk factors were analyzed using the logistic regression model. Out of all children, 76 (4.31 per 1000) children had documented maltreatment including 69 (4.03 per 1000) singletons and seven (14.31 per 1000) twins. All of the cases in twins were physical abuse (100%) and nearly half of the cases (43%) included emotional abuse. Among twins, 86% of the biological mothers were suspected. The alleged perpetrators of twins showed a significantly higher rate of maternal depression compared to those of singletons. After adjusting the results for a number of potential biological and social risk factors, twins or triplets had a higher risk for maltreatment than singletons ( 3.39, 95% CI [1.17, 9.83]). Healthcare providers should be aware that a multiple birth can place considerable stress on a family leading to child maltreatment and should provide appropriate support and intervention for mothers with multiples.
Polygenic Selection and Environmental Influence on Adult Body Height: Genetic and Living Standard Contributions Across Diverse Populations.
Piffer D, Kirkegaard EOW
Twin Res Hum Genet · 2024 Dec · PMID 39639460 · Publisher ↗
We analyzed whole-genome sequencing (WGS) data from 51 populations and combined WGS and array data from 89 populations. Multiple types of polygenic scores (PGS) were employed, derived from multi-ancestry, between-family...
We analyzed whole-genome sequencing (WGS) data from 51 populations and combined WGS and array data from 89 populations. Multiple types of polygenic scores (PGS) were employed, derived from multi-ancestry, between-family genome-wide association study (GWAS; MIX-Height), European-ancestry, between-family GWAS (EUR-Height), and European-ancestry siblings GWAS (SIB-Height). Our findings demonstrate that both genetic and environmental factors significantly influence adult body height between populations. Models that included both genetic and environmental predictors best explained population differences in adult body height, with the MIX-Height PGS and environmental factors (Human Development Index [HDI] + per capita caloric intake) achieving an of .83. Our findings shed light on Deaton's 'African paradox', which noted the relatively tall stature of African populations despite poor nutrition and childhood health. Contrary to Deaton's hypotheses, we demonstrate that both genetic differences and environmental factors significantly influence body height in countries with high infant mortality rates. This suggests that the observed tall stature in African populations can be attributed, in part, to a high genetic predisposition for body height. Furthermore, tests of divergent selection based on the Q (i.e., standardized measure of the genetic differentiation of a quantitative trait among populations) and F (neutral marker loci) measures exceeded neutral expectations, reaching statistical significance ( < .01) with the MIX-Height PGS but not with the SIB-Height PGS. This result indicates potential selective pressures on body height-related genetic variants across populations.
The Role of Sibling Patterns in the Educational Attainment of Hungarian Twins.
Pári A, Engler Á
Twin Res Hum Genet · 2024 Aug · PMID 39523894 · Publisher ↗
Studies concerning twins with a sociological focus are scarce in Hungary as well as international research, although the number of twin births has increased dramatically worldwide. The raising and education of twins are...
Studies concerning twins with a sociological focus are scarce in Hungary as well as international research, although the number of twin births has increased dramatically worldwide. The raising and education of twins are tasks demanding special attention from both the family and institutions. In our study we examine these aspects, looking back from adulthood, using the narrow scope of the available data from research based on the 'Hungarostudy 2021' database ( total: 7000; twins: 106). Our results, corresponding to the hypotheses of educational sociology, demonstrate how the relationships between family size and school career and increasing number of siblings reduces the chances of high educational attainment. A regression analysis confirmed that both the number of siblings and a later position in the birth order reduces the chance of obtaining a higher education. For the second child in a family, the chance of earning a university degree is reduced to to 0.743. The role of a large family concerning higher education showed a stronger relationship in the case of twins compared to nontwins. For twins, the sibling pattern has a decisive effect in educational attainment. Twins themselves have a 1.449 times higher chance of obtaining a higher education compared to nontwins ( = 0.101), and fraternal twins have half (0.517) the chance of obtaining a higher education compared to identical twins; but both results are not significant ( = 0.156).
Placental Vascular Anastamoses and Associated Pathologies in Dichorionic Twin Gestations.
Dave E, Ozan Bahtiyar M, Campbell W … +2 more , Morotti R, Kohari K
Twin Res Hum Genet · 2024 Aug · PMID 39508257 · Publisher ↗
Placental vascular anastomoses are traditionally thought to exist exclusively in monochorionic pregnancies. However, they have been reported in dichorionic twin pregnancies as well. In turn, twin to twin transfusion synd...
Placental vascular anastomoses are traditionally thought to exist exclusively in monochorionic pregnancies. However, they have been reported in dichorionic twin pregnancies as well. In turn, twin to twin transfusion syndrome (TTTS) and twin anemia polycythemia sequence (TAPS) have also been noted to impact some of these gestations. Through discussion of one such case at our institution along with a review of the available literature, we review the proposed pathophysiology of placental vascular anastamoses in dichorionic twin gestations, and aim to raise awareness of the possibility of associated pathologies in dichorionic gestations. This is an emerging area of literature that will require future study to guide prenatal surveillance and mitigate morbidity.
Trends in Twin Births and Survival in Rural Spain: Evidence from 18th to 20th Century.
Marco-Gracia FJ
Twin Res Hum Genet · 2024 Nov · PMID 39506863 · Publisher ↗
This study examines the changes over time of the twinning rate and infant and child mortality across 17 rural villages in the province of Zaragoza (Spain) over a span of 200 years. The aim is to understand how the twinni...
This study examines the changes over time of the twinning rate and infant and child mortality across 17 rural villages in the province of Zaragoza (Spain) over a span of 200 years. The aim is to understand how the twinning rate evolved in conjunction with the processes of economic and social modernization, as well as the demographic transition. During the period analyzed, the twinning rate increased by 10%, rising from 1.26 per 1000 births in the second half of the 18th century to 1.38 per 1000 births in the first half of the 20th century. This rate varied due to hereditary issues, biological factors such as the mother's age and parity, and socioeconomic features like family occupation and the mother's education level. In terms of child mortality, twins historically faced a significantly higher mortality rate. However, they benefited greatly from the mortality transition, at least in absolute numbers. While nearly 60% of twins did not survive beyond 5 years of age in earlier periods, the mortality rate for twins decreased to 40% by the first half of the 20th century. The excess mortality was particularly severe for girls, driven by a widespread preference for sons, which led to higher mortality rates for girls in the first 5 years of life, especially in the earliest months. These findings help us understand the improvements in uterine and childhood survival rates for contemporary twins, which can be attributed to the socioeconomic and medical advancements of the 20th century.
Common Genetic Influence on the Relationship Between Gaming Addiction and Attention Deficit Hyperactivity Disorder in Young Adults: A Twin Study.
Lee SA, Hur YM
Twin Res Hum Genet · 2024 Aug · PMID 39463167 · Publisher ↗
Although the relationship between gaming addiction (GA) and attention deficit hyperactivity disorder (ADHD) is well established, the causal mechanism of this relationship remains ambiguous. We aimed to investigate whethe...
Although the relationship between gaming addiction (GA) and attention deficit hyperactivity disorder (ADHD) is well established, the causal mechanism of this relationship remains ambiguous. We aimed to investigate whether common genetic and/or environmental factors explain the GA-ADHD relationship. We recruited 1413 South Korean adult twins (837 monozygotic [MZ], 326 same-sex dizygotic [DZ], and 250 opposite-sex DZ twins; mean age = 23.1 ± 2.8 years) who completed an online survey on GA and related traits. Correlational analysis and bivariate model-fitting analysis were conducted. Phenotypic correlation between GA and ADHD in the present sample was 0.55 (95% CI [0.51, 0.59]). Bivariate model-fitting analysis revealed that genetic variances were 69% (95% CI [64%, 73%]) and 68% (95% CI [63%, 72%]) for ADHD and GA respectively. The remaining variances (ADHD: 31%; GA: 32%) were associated with nonshared environmental variances, including measurement error. Genetic and nonshared environmental correlations between ADHD and GA were 0.68 (95% CI [0.62, 0.74]) and 0.22 (95% CI [0.13, 0.30]) respectively, which indicates that shared genes can explain 82% of the phenotypic correlation between ADHD and GA. Our study demonstrated that the ADHD-GA association was largely due to shared genetic vulnerability.
Chorionicity and Psychomotor Development From Infancy to Childhood: The Japan Environment and Children's Study.
Silventoinen K, Honda C, Tomizawa R … +8 more , Sakai N, Ikehara S, Miyazaki J, Tanigawa K, Kimura T, Kawasaki R, Iso H, Japan Environment and Children’s Study Group
Twin Res Hum Genet · 2024 Oct · PMID 39463157 · Publisher ↗
Twins lag behind singletons in their early psychomotor development, but little is known about how chorionicity affects this difference. We compared early psychomotor development in singletons, monochorionic (MC) twins an...
Twins lag behind singletons in their early psychomotor development, but little is known about how chorionicity affects this difference. We compared early psychomotor development in singletons, monochorionic (MC) twins and dichorionic (DC) twins. Our longitudinal data from the Japan Environment and Children's Study (JECS; see Appendix) included 98,042 singletons, 577 MC twins and 1051 DC twins representing the general Japanese population. Chorionicity was evaluated by ultrasound images and complemented by postnatal pathological examinations. Five domains of psychomotor development were evaluated at 6 time points from 6 months to 3 years of age using the Ages and Stages Questionnaires (ASQ-3). The data were analyzed using linear regression models. Twins lagged behind singletons in all areas of psychomotor development during infancy. This gap decreased over time but was still noticeable at 3 years of age. More than half of this difference was attributed to twins having lower birth weight and being born earlier in gestation. MC twins showed slightly delayed development compared to DC twins, but this difference was minor compared to the overall gap between twins and singletons. Twins delay singletons in their early psychomotor development, and this delay is not specific to MC twinning.
Exploring the Link Between Parental Sociodemographic Characteristics and Multiple Births: Insights from National Birth Data in Japan, 1995-2020.
Okui T, Nakashima N
Twin Res Hum Genet · 2024 Aug · PMID 39360484 · Publisher ↗
This present study investigated the parental characteristics of multiple births using national birth data in Japan. This study included birth data from Vital Statistics: Occupational and Industrial Aspects every five fis...
This present study investigated the parental characteristics of multiple births using national birth data in Japan. This study included birth data from Vital Statistics: Occupational and Industrial Aspects every five fiscal years from 1995 to 2020. The multiple birth rates were defined as the number of live-birth deliveries with multiple fetuses (e.g., twins, triplets) per total live-birth deliveries. Parental ages, nationalities, occupations and household occupation (occupation of the top earner of the household) were considered as parental characteristics. The multiple birth rates were calculated based on parental characteristics for each year, and a log-binomial regression model was used to assess the association between parental characteristics and multiple births. The multiple birth rate for Japanese mothers consistently exceeded that for non-Japanese mothers over the years, and the rate increased progressively from manual workers to lower non-manual workers and then to upper non-manual workers for both maternal and paternal occupations. The regression results indicated that the risk ratio (RR) for multiple births among non-Japanese mothers was significantly lower than that among Japanese mothers. Moreover, concerning household occupation, the RRs of self-employed individuals, full-time employees at smaller companies, others, and the unemployed were significantly lower than those of full-time employees at larger companies. Furthermore, the RRs of lower non-manual and manual workers were significantly lower than those of upper non-manual workers in maternal and paternal occupations. The results suggested an association between multiple births and parental socioeconomic status in Japan.
Breastfeeding Practices in the Twin Town of India - A Cross-Sectional Study.
Bhardwaj G, Smitha MV
Twin Res Hum Genet · 2024 Aug · PMID 39355965 · Publisher ↗
The global rise in twinning rates poses health challenges due to increased risks for infants and mothers. Despite the benefits, breastfeeding rates among multiples are low, with exclusive breastfeeding (EBF) particularly...
The global rise in twinning rates poses health challenges due to increased risks for infants and mothers. Despite the benefits, breastfeeding rates among multiples are low, with exclusive breastfeeding (EBF) particularly scarce compared to singletons. Our study focuses on the mothers of twins in a unique population in Kodinhi village, Kerala, India, known for its high twinning rates, which aims to contribute to existing knowledge of breastfeeding practices and perspectives in a high twinning environment and offer valuable insights to promote optimal breastfeeding among mothers of twins. A retrospective cross-sectional survey was adopted. Seventy-five mothers with twins under 3 years of age from Kodinhi and neighboring areas were interviewed face to face using structured validated tools. Data collection focused on quantitative data supplemented by narrative descriptions. Most women delivered preterm (57.3%), operative delivery (58.7%), and had a late initiation of breastfeeding (32.9% within 24 hours). Colostrum feed was common (86.7%). The EBF rate was 4%, with 47.9% initiating nonexclusive breastfeeding before 3 months, and most of the twins (46.6%) were breastfed for 1-2 years. Fatigue (69.9%) and low milk supply (38.7%) were chief concerns. While 16.4% of mothers opted for a tandem breastfeeding technique, many preferred consecutive feeding as tandem was challenging. Mothers in Kodinhi demonstrated commendable efforts in breastfeeding twins; despite the low rate of EBF, breastfeeding extended to 1-2 years. Evidence-based interventions and personalized support, primarily focusing on maternal perspectives of milk insufficiency, fatigue and breastfeeding techniques, are crucial for sustaining optimal breastfeeding practices among mothers of twins.
Zygosity Effects on Human Voice: Fundamental Frequency Analysis of Brazilian Twins' Speech.
Luchesi LC, Cavalcanti JC, Lucci TK … +3 more , David VF, Otta E, Monticelli PF
Twin Res Hum Genet · 2024 Aug · PMID 39355961 · Publisher ↗
Voice production can be influenced by interindividual variations related to genetic, physiological, behavioral, and several environmental factors. Here we examined the effect of zygosity on speaking fundamental frequency...
Voice production can be influenced by interindividual variations related to genetic, physiological, behavioral, and several environmental factors. Here we examined the effect of zygosity on speaking fundamental frequency (F0) statistical descriptors. Our aims were: (1) to determine whether the genetic similarity between monozygotic (MZ) and dizygotic (DZ) twins affects F0 characteristics, and (2) to quantify the contribution of genetic factors to these characteristics. The study involved 79 same-sex twin pairs of Brazilian Portuguese speakers, comprising 65 MZ and 14 DZ twins, aged 18 to 66 years (31.7 ± 11.6 years), with 21 male and 58 female pairs. Participants were recorded while uttering a greeting phrase and the Brazilian Portuguese version of the 'Happy Birthday to You' song. Speech segments were analyzed using Praat free software, and F0 measures were automatically extracted in both Hertz and semitone scales. Statistical descriptors, including centrality, dispersion, and extreme values of F0 were examined, and the ACE model (i.e., total genetic effects, A; shared environmental influences, C; and nonshared environmental influences, E) was employed to estimate the additive effect;ts of monozygosity. As anticipated, we observed a zygosity effect on several F0 parameters, with more similarity between MZ twins compared to DZ twins. We discuss the genetic influences on F0 parameters and the absence of a monozygosity effect in two of them. Additionally, we briefly address potential biases associated with the selected measurement scale for statistical modeling. Finally, we explore the influence of genetic factors on F0 patterns, as well as environmental, life history and linguistic factors, particularly concerning F0 variation in speech.
Genetic Influence on Social Support: A Twin Study.
Gonggrijp BMA, van de Weijer SGA, van Dongen J … +2 more , Bijleveld CCJH, Boomsma DI
Twin Res Hum Genet · 2024 Aug · PMID 39355956 · Publisher ↗
Social support is often considered an environmental factor affecting health, especially in aging populations. However, its genetic underpinnings suggest a more complex origin. This study investigates the heritability of...
Social support is often considered an environmental factor affecting health, especially in aging populations. However, its genetic underpinnings suggest a more complex origin. This study investigates the heritability of social support through applying a threshold model on data of a large adult sample of twins ( = 8019) from the Netherlands Twin Register, collected between 2009 and 2011. The study employed the Duke - UNC Functional Social Support Questionnaire to assess social support quality. Our analysis revealed genetic contributions to social support, with heritability estimated at 37%, without a contribution of shared environment and no differences between men and women in heritability. The study's results underscore the complexity of social support as a trait influenced by genetic and environmental factors, challenging the notion that it is solely an environmental construct.
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