A School-based Twin Study of Handedness among Adolescents in Taiwan

Abstract

This study aimed to evaluate whether twinning might influence handedness and the relative contribution of genetic and environmental factors to handedness in a total of 321 pairs of twins, 36 same-sex sib-pairs, and 1020 singletons, aged 12-16 and systematically recruited from the junior high schools in Taipei. Twins' zygosity was determined by a combination of DNA typing and physical similarity. The direction and consistency of handedness in twins did not differ from that seen in singletons. Compared with the full model containing additive genes (A), shared (C), and non-shared (E) environment, both AE and CE models had equivalently acceptable fit. The contribution from additive genes in the AE model was estimated to be 16% (directional) to 13% (consistent) for the continuous handedness and 34-10% for the categorical one, whereas the corresponding contribution from shared environment in the CE model was 14-14% and 32-11%, respectively. Handedness in adolescents appears to be not influenced by twinning and not substantially heritable, whereas environmental factors, especially those not shared between siblings, are the most important ones for explaining individual variations.

Exploring gene–culture interactions: insights from handedness, sexual selection and niche-construction case studies

“…While isolated studies (e.g. Warren et al 2006) have reported positive heritabilities for some handedness measures, the overall picture across multiple studies remains that handedness, at least as measured in the vast majority of questionnaire and performance studies, does not exhibit strong heritability (McManus 1985;Neale 1988;Su et al 2005).…”

Genetic and Environmental Influences on Schizotypy among Adolescents in Taiwan: A Multivariate Twin/sibling Analysis

“…The sampling of the participants has been described in detail elsewhere (Kuo et al 2004;Su et al 2005). In brief, a list of twins was solicited from the 71 junior high schools in Taipei City.…”

The Taipei Adolescent Twin/Sibling Family Study I: Behavioral Problems, Personality Features, and Neuropsychological Performance

“…This study (Su et al, 2005) aimed to evaluate whether twinning influences handedness and the relative contribution of genetic and environmental factors to handedness. In total, we have complete handedness data from 357 twin/sibling pairs , consisting of 233 MZ twin pairs (128 female, 105 male), 46 same-sex DZ twin pairs (24 female, 22 male), 36 same-sex sibling pairs (23 female, 13 male), and 42 OS pairs.…”