Finger ridge-count variability in Sub-Saharan Africa

Abstract

Mean finger ridge-count data were obtained, primarily from literature sources, for 31 male and 24 female sub-Saharan African samples. The 10 finger ridge-counts and total ridge-count were used as independent variables in a multiple regression analysis, latitude and longitude serving in turn as the dependent variables. The results show that it is not the magnitude of the ridge-counts themselves that is important, but rather contrasts between groups of digits. The most important geographically patterned variation in ridge-counts consists of contrasts between digits 4 and 5 and digits 2 and 3. South and south-east African populations are characterized by low contrasts, west Africans by high contrasts and, south-west Africans are intermediate. The geographical patterning of the contrast agrees well with known patterns of gene flow into and within the continent as determined by serological genes. Principal components analysis was also carried out to determine whether within-group components corresponding to the geographically relevant between-group variation could be identified. The third, fourth and fifth components drew the same types of contrasts between the groups of digits identified in the multiple regression analysis, but they were relatively unimportant. The geographically important principal components would have been overlooked in a traditional multivariate analysis of finge ridge-counts, since the analysis would have been dominated by pattern size. We conclude that finger ridge-counts are potentially very useful in population studies, but account must be taken of their multicomponent nature.

Fluctuating asymmetry in quantitative dermatoglyphic traits: twins and singletons

“…The results obtained by several authors support the idea that, although both sides (radial and ulnar, form a part of the same finger, they follow different development instructions (ROBERTS and COOPE 1975;JANTZ and OWSLEY 1977;JANTZ and HAWKINSON 1979;MEIER 1981;LIN et al 1983;and ARRIETA and LOSTAO 1988). These results reinforce the importance of using the radial and ulnar counts as separate variables.…”

Dermatoglyphic analysis of autistic Basque children

“…Roberts and Coope [19751, Mi and Rashad [19751, Reed et al 119751, Loesch 119791, and other investigators have shown a certain degree of independence of ulnar and radial counts. Although both sides are part of the same finger, they seem to respond to different developmental instructions [Roberts and Coope, 1975;Jantz and Owsley, 1977;Jantz and Hawkinson, 1979;Lin et al, 19831 Results of genetic studies of a-b interdigital ridge count also indicate an additive type of inheritance [Fang, 1950;Pons, 19641. In regard to the atd angle, the fact that the observed correlation between parents and children is lower than the sib-pair correlation [Penrose, 19541 suggests that recessive genes may be involved on polygenic inheritance. Gilligan et al [ 19871 came to the same conclusion.…”

Principal component of finger ridge-counts: their universality

“…The need for a multivariate approach to finger ridge-counts and the advantages it offers, compared to the summary measures such as TFRC/ATFRC, in tracing population relationships at local and racial levels has been amply demonstrated (Knussmann 1967, Chopra 1971, Jantz and Owsley 1977, Jantz and Hawkinson 1979, 1980, Jantz, Hawkinson, Brehme and Hitzeroth 1982. Many of the above studies show interpopulation consistency in the components derived, within major racial/geographical stocks, suggesting biological validity of the underlying component structure obtained by principal component analysis.…”