Segregation analysis of a-b ridge count in human palms

Frequency distribution and segregation analyses have been performed on a-b ridge counts from 422 families. The results support the hypothesis of two commingled distributions of the trait, high-value distributions being 5.4% in females and 2.4% in males of the whole population. Segregation analyses point out evidence for simultaneously a multi-factorial inheritance (h = 0.72) and a major effect (P = 0.01). However, by testing different hypotheses on transmission laws for the major effect, we cannot decide between Mendelian transmission and no transmission. Hypothesis of an accident occurring in the developmental process of the a-b count has to be investigated further.