Browsing by Subject "Twins"

Now showing 1 - 4 of 4
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    A longitudinal study of epigenetic variation in twins.
    (Epigenetics, 2010-08-16) Wong, Chloe Chung Yi; Caspi, Avshalom; Williams, Benjamin; Craig, Ian W; Houts, Renate; Ambler, Antony; Moffitt, Terrie E; Mill, Jonathan
    DNA methylation is a key epigenetic mechanism involved in the developmental regulation of gene expression. Alterations in DNA methylation are established contributors to inter-individual phenotypic variation and have been associated with disease susceptibility. The degree to which changes in loci-specific DNA methylation are under the influence of heritable and environmental factors is largely unknown. In this study, we quantitatively measured DNA methylation across the promoter regions of the dopamine receptor 4 gene (DRD4), the serotonin transporter gene (SLC6A4/SERT) and the X-linked monoamine oxidase A gene (MAOA) using DNA sampled at both ages 5 and 10 years in 46 MZ twin-pairs and 45 DZ twin-pairs (total n=182). Our data suggest that DNA methylation differences are apparent already in early childhood, even between genetically identical individuals, and that individual differences in methylation are not stable over time. Our longitudinal-developmental study suggests that environmental influences are important factors accounting for interindividual DNA methylation differences, and that these influences differ across the genome. The observation of dynamic changes in DNA methylation over time highlights the importance of longitudinal research designs for epigenetic research.
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    Disputes over memory ownership: What memories are disputed?
    (Genes Brain Behav, 2006) Sheen, M; Kemp, S; Rubin, DC
    The ownership of memories is sometimes disputed, particularly by twins. Examination of 77 disputed memories, 71 provided by twins, showed that most of the remembered events are negative and that the disputants appear to be self-serving. They claim for themselves memories for achievements and suffered misfortunes but are more likely to give away memories of personal wrongdoing. The research suggests that some of the memories in which we play a leading role might in fact have been the experiences of others.
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    Influence of host genetics and environment on nasal carriage of staphylococcus aureus in danish middle-aged and elderly twins.
    (J Infect Dis, 2012-10) Andersen, Paal Skytt; Pedersen, Jacob Krabbe; Fode, Peder; Skov, Robert L; Fowler, Vance G; Stegger, Marc; Christensen, Kaare
    BACKGROUND: Nasal carriage is a major risk factor for Staphylococcus aureus infection. Approximately, one-quarter of adults carry S. aureus. However, the role of host genetics on S. aureus nasal carriage is unknown. METHODS: Nasal swabs were obtained from a national cohort of middle-aged and elderly Danish twins. Subjects colonized with S. aureus were identified by growth on selective plates and spa typing. A second sample was obtained from twins initially concordant for carriage. Twins found to again be colonized with S. aureus were defined as persistent carriers. RESULTS: The prevalence of S. aureus carriage among 617 twin pairs (monozygotic/dizygotic pairs: 112/505) was 26.3% (95% confidence interval [CI], 24.0%-28.9%). The concordance rate for carriage did not differ significantly between pairs of monozygotic (37.5%; 95% CI, 22.3%-53.8%) twins and same sex (24.2%; 95% CI, 15.4%-34.5%), and opposite sex (21.4%; 95% CI, 12.0%-33.4%) dizygotic twins. Despite shared childhoods, only 1 of 617 pairs was concordant with respect to lineage. Although heritability increased for S. aureus and lineage persistency, no significant heritability was detected. CONCLUSION: In this study, host genetic factors exhibited only a modest influence on the S. aureus carrier state of middle-aged and elderly individuals.
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    The Danish Twin Registry: linking surveys, national registers, and biological information.
    (Twin Res Hum Genet, 2013-02) Skytthe, Axel; Christiansen, Lene; Kyvik, Kirsten Ohm; Bødker, Frans L; Hvidberg, Lars; Petersen, Inge; Nielsen, Morten MF; Bingley, Paul; Hjelmborg, Jacob; Tan, Qihua; Holm, Niels V; Vaupel, James W; McGue, Matt; Christensen, Kaare
    Over the last 60 years, the resources and the research in the Danish Twin Registry (DTR) have periodically been summarized. Here, we give a short overview of the DTR and a more comprehensive description of new developments in the twenty-first century. First, we outline our experience over the last decade of combining questionnaire and survey data with national demographic, social, and health registers in Statistics Denmark. Second, we describe our most recent data collection effort, which was conducted during the period 2008-2011 and included both in-person assessments of 14,000+ twins born 1931-1969 and sampling of biological material, hereby expanding and consolidating the DTR biobank. Third, two examples of intensively studied twin cohorts are given. The new developments in the DTR in the last decade have facilitated the ongoing research and laid the groundwork for new research directions.