Dermatoglyphic total patterns on palms, finger-tips and soles in twins.

110 palms of MZ twins and 111 like-sexed pairs of DZ twins have been compared in respect of a concordance rate of the palmar, sole and finger-tip total pattern types. Dermatoglyphic patterns have been classified according to the topological method, and the distributions of the numbers of discordant pattern elements from homolateral, heterolateral and bilateral comparisons in MZ and DZ twins, respectively, are presented. The highest concordance occurs in homolateral comparisons in MZ twins and the lowest in heterolateral comparisons. Bilateral concordance is highest for sole and finger-patterns, while palmar patterns present a considerable degree of dermatoglyphic asymmetry. Palmar, sole and finger-tip patterns are also not alike in homolateral concordance rates within MZ and DZ twin pairs. The differences between MZ and DZ twins are much more pronounced for sole patterns than for palmar or finger-tip patterns, which is also reflected in the estimated H values. For soles, this may be in some way related to the considerable symmetry of patterns. The fact that some pattern elements are intercorrelated may also introduce a bias in estimates of heritability, based on twin material.