Twin Pair Analysis of Some Palm Indexes

The heritability of two main line indexes (DLI and TLI), a palm crease index (API), and an ulnarity index (UI) were investigated by using twin pair methodology for quantitative traits. The analyses of the data allow to conclude that both DLI and API, which have been used to evaluate the obliquity of the main lines and the distal crease of the palm, should not be considered as depending upon an important genetic component. Otherwise, data on TLI and UI, while showing inconsistencies with the theoretical expectations, may be considered as genetic traits.