title: Hand preference in humans is associated with testosterone levels and androgen receptor gene polymorphism.
abstract: Exposure of the central nervous system to androgens during the early developmental period has been proposed to play a role in the establishment of hand preference in males. Existing data, however, are inconclusive. In the present investigation, handedness was assessed in a large sample of left-, mixed-, and right-handed men (N=180) using a standardized handedness inventory. Saliva sampling was used to assay levels of bioavailable testosterone and DNA genotyping was carried out to quantify AR-CAG repeat length, a genetic marker of the capacity of the androgen receptor to respond to testosterone. Strongly left-handed males were found to have lower levels of bioavailable testosterone than right-handed males, while males with mixed handedness exhibited a weaker androgen receptor, but no significant difference from right-handers in circulating testosterone levels. These findings support the view that testosterone could play a role in the development of hand preference in males. Furthermore, because the AR gene lies on the X chromosome, it provides a potential theoretical bridge to genetic theories of handedness that postulate the existence of an X-linked locus important in the establishment of hand preference.
authors.affiliation: Department of Psychology, University of Western Ontario, London, ON, Canada N6A 5C2. ehampson@uwo.ca
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Hampson
authors.forename: Janani S
authors.initials: JS
authors.lastname: Sankar
mesh_terms: D000293:Adolescent; D015415:Biomarkers; D007839:Functional Laterality / Q000235:genetics* / Q000502:physiology; D050172:Genes, X-Linked / Q000235:genetics*; D005838:Genotype; D006801:Humans; D008297:Male; D011110:Polymorphism, Genetic; D011944:Receptors, Androgen / Q000235:genetics* / Q000502:physiology; D012463:Saliva / Q000737:chemistry; D013739:Testosterone / Q000032:analysis*; D019680:Trinucleotide Repeat Expansion; D055815:Young Adult
chemical_list: C410798:AR protein, human; D015415:Biomarkers; D011944:Receptors, Androgen; D013739:Testosterone