Odontometric asymmetry in Punjabi twins with special reference to methods for detecting spurious genetic variance.

Bilateral human odontometric asymmetry generally shows very little genetic variance. In Indian twins, using the simplest methods, unusual levels of disproportionate monozygous similarity and/or dizygous dissimilarity for asymmetry, giving the appearance of significant genetic determinance, were found. Thus this dental asymmetry constituted an interesting test case for the application of more exact methods for the detection of zygosity bias; these invalidated the spuriously significant genetic variance ratios. Therefore the predominantly environmental influences on bilateral dental asymmetry are confirmed.