LOCATION OF THE HANDEDNESS GENE ON THE X-CHROMOSOME AND Y-CHROMOSOME

Accumulated data from five handedness surveys show that concordance fo r sex is slightly but reliably higher among siblings of the same hande dness than among those of opposite handedness. This is consistent with Crow's theory that the genetic locus for handedness is in an X-Y homo logous region of the sex chromosomes. The small size of the effect is predicted from genetic models in which there is a substantial random c omponent underlying phenotypic left handedness. The findings are relev ant to the putative role of cerebral asymmetry in the aetiology of psy chosis. (C) 1996 Wiley-Liss, Inc.