Principal components of finger ridge-counts: their universality

A principal component analysis was carried out on radial and ulnar finger ridge-count data on a sample of fishermen of the sea coast of Puri in the state of Orissa in India. The component structure is very similar to that obtained earlier by Roberts and Coope for some English populations, by Arrieta and Lostao for a Basque population, by Siervogel et al. for a White American population, by Jantz and Hawkinson, and Jantz et al. for American and African populations, and by other authors for other populations. The initial components are bilaterally symmetric and the structure of these components is the same whether the two sides are taken separately or together. Only the latter components represent a certain amount of bilateral asymmetry. The first component is a 'size' component, indicating total finger ridge-count; the second component is a radial-ulnar contrast. From a comparison with previous studies on other populations, it appears that the component structure corresponding to the larger eigenvalues is fairly universal; there is a certain lack of universality in the structure of the components corresponding to smaller eigenvalues as well as in the order of these components, especially the rotated ones, when the corresponding eigenvalues are very close. As observed by previous authors, components corresponding to larger eigenvalues do not necessarily exhibit larger inter-population differences. However, there is lack of universality in the order of the components and in the structure of the components that exhibit large inter-population differences.