Heritability and linkage analysis of hand, foot, and eye preference in Mexican Americans.

Functional lateralities are of interest due to their relationship with cerebral lateralisation and language development. However, genes influencing sidedness remain elusive. We measured direction and consistency of hand, foot, and eye preference in 584 Mexican-Americans from families participating in the San Antonio Family Diabetes/Gallbladder Study. Using maximum-likelihood-based variance components methods, we estimated weak (.11 <or= h2<or=.17) but significant heritability for foot preference, eye preference, several hand preferences (writing, drawing, throwing, using scissors, using spoon, striking match), and a composite hand preference trait. Self-reported handedness was significantly heritable (h2=.57), whereas hand preference for opening a box or using a toothbrush or knife was not. Many trait pairs had significant genetic correlations, and all had significant environmental correlations. Using genome-wide multipoint linkage screens using 382 highly informative autosomal STR markers, we identified suggestive linkage signals for drawing (LOD 2.10) and writing (LOD 2.00) hand preference on chromosome 12q21-23, in the region flanked by markers D12S1300 and PAH. A suggestive signal (LOD 2.46) for eye preference occurred on chromosome 22pter, near marker D22S420. No obvious candidate genes occur in these regions. Our results indicate that genes are an important component of side preferences, and suggest chromosomal regions for further investigation.