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Browsing by Subject "Twin study"

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  • Seesjärvi, Erik (2014)
    The aim of the study was to estimate the proportional effects of genetic and environmental factors on individual differences in music perception. Previous research has demonstrated that genetic effects explain a substantial amount of these differences, and that common environmental effects have been low or have not been examined because of methodological constraints. However, in defining the accuracy of music perceptual skills, most previous studies have used somewhat simple auditory stimuli this choice limiting their generalizability. In order to reliably determine the proportional effects of genetic and environmental factors on perception of more complex musical stimuli, the present study utilized unfamiliar melodies, the classical twin design, and structural equation modelling. The participants of the current study were 384 twins from the longitudinal FinnTwin16 study, aged 32–38 years. They performed an online music perception test that consists of two subtests with pitch-related tasks (Scale and Out-of-key subtests) and one subtest with a time-related task (Off-beat subtest). The test includes 30 unfamiliar melodies. The participants also answered a short questionnaire regarding their educational background and self-assessed musical ability. The results showed that genetic factors explained about half of the interindividual variance in ability to detect pitch changes in repeated melodies (Scale subtest), whereas common environmental factors had only marginal effect on this ability. Furthermore, genetic factors explained about a quarter or less of the interindividual variance in ability to detect a timing delay that was disrupting the meter or rhythm of melody (Off-beat subtest). There were no common environmental effects. In contrast, a different pattern of results was obtained for ability to detect a tone that violated the established scale expectations (Out-of-key subtest) in which there were only marginal genetic effects whereas common environmental factors explained over half of the interindividual variance. Together with the previous research, these results show that genetic factors explain a significant portion of the individual differences in music perception tasks especially when the task is sufficiently demanding cognitively. However, when the task demands explicit or implicit knowledge of musical scales, genetic effects disappear and the individual differences can mostly be explained by common environmental factors.
  • Jukarainen, Sakari; Heinonen, Sini; Rämö, Joel; Rinnankoski-Tuikka, Rita; Rappou, Elisabeth; Tummers, Mark; Muniandy, Maheswary; Hakkarainen, Antti; Lundbom, Jesper; Lundbom, Nina; Kaprio, Jaakko; Rissanen, Aila; Pirinen, Eija; Pietiläinen, Kirsi (2016)
    Context: Sirtuins (SIRTs) regulate cellular metabolism and mitochondrial function according to the energy state of the cell reflected by NAD+‚ levels. Objective: Our aim was to determine whether expressions of SIRTs and NAD+‚ biosynthesis genes are affected by acquired obesity and how possible alterations are connected with metabolic dys-function while controlling for genetic and familial factors. Design and Participants: We studied a cross-sectional sample of 40 healthy pairs of monozygotic twins, including 26 pairs who were discordant for body mass index (within-pair difference +ƒ 3 kg/m2), from the FinnTwin12 and FinnTwin16 cohorts. Main Outcome Measures: Subcutaneous adipose tissue (SAT) transcriptomics was analyzed by using Affymetrix U133 Plus 2.0 chips, total SAT (poly-ADP) ribose polymerase (PARP) activity by an ELISA kit, body composition by dual-energy x-ray absorptiometry and magnetic resonance imaging/spectroscopy, and insulin sensitivity by an oral glucose tolerance test. Results: SIRT1, SIRT3, SIRT5, NAMPT, NMNAT2, NMNAT3, and NRK1 expressions were significantly down-regulated and the activity of main cellular NAD+‚ consumers, PARPs, trended to be higher in the SAT of heavier cotwins of body mass index–discordant pairs. Controlling for twin-shared factors, SIRT1, SIRT3, NAMPT, NMNAT3, and NRK1 were significantly negatively correlated with adiposity, SIRT1, SIRT5, NMNAT2, NMNAT3, and NRK1 were negatively correlated with inflammation, and SIRT1 and SIRT5 were positively correlated with insulin sensitivity. Expressions of genes involved in mitochondrial unfolded protein response were also significantly down-regulated in the heavier cotwins. Conclusions: Our data highlight a strong relationship of reduced NAD+‚/SIRT pathway expression with acquired obesity, inflammation, insulin resistance, and impaired mitochondrial protein homeostasis in SAT.