1. ¹Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Australia
2. ²Department of Paediatrics, The University of Melbourne, Melbourne, Victoria 3052, Australia
3. ³Australian Genome Research Facility, Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria 3052, Australia
4. ⁴Department of Molecular Genetics, Flanders Interuniversity Institute for Biotechnology (VIB), University of Antwerp (UIA), 2610 Antwerpen, Belgium

Correspondence: Dr Van Agtmael, MRC Human Genetics Unit, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK. Tel: +44 131 332 2471; Fax: +44 131 467 8456; E-mail: tom.vanagtmael@hgu.mrc.ac.uk

Received 28 January 2003; Revised 16 April 2003; Accepted 7 May 2003.

Abstract

We have performed a genome scan using 25 nuclear families consisting of right-handed parents with at least two left-handed children. Handedness was assessed as a qualitative trait using a laterality quotient. Laterality quotients indicate the direction of handedness, which is hand preference for performing unimanual tasks. Both parametric and nonparametric linkage analyses were applied. The parametric analysis using the single-locus genetic model of Klar resulted in four different regions with LOD scores higher than 1. The region on chromosome 10q26 gave a suggestive LOD score of 2.02 at a recombination fraction of 0.05. Nonparametric analysis gave an NPL score for this region of 2.16. However, further fine mapping of the region on chromosome 10q26 failed to obtain a higher LOD score. These results suggest that handedness is a human quantitative trait locus and that the proposed non-Mendelian monogenic models are incorrect.