Fingerprint ridge density in the Argentinean population and its application to sex inference: A comparative study.

Fingerprint ridge density (RD) is known to vary according to sex and population, and such variation can be used for forensic purposes. The aim of this study was to analyze the fingerprint RD of two samples of the Argentinean population in order to assess their topological, digital, bilateral, sexual, and population differences for subsequent application in the inference of sex. Data were collected from the fingerprints of 172 individuals from the Buenos Aires province and 163 from the Chubut province. RD was assessed for three different count areas for all 10 fingers of each individual. In both sexes and both samples, significant differences among areas were obtained, so that radial-RD>ulnar-RD>proximal-RD. Females presented greater RD than males in all areas and on all fingers. Regarding population differences, no significant differences were found between the Buenos Aires and Chubut samples (except for proximal RD in males). However, both samples showed RD significantly different from that of the Jujuy province. The application of Bayes' theorem allowed for the identification of an RD threshold for discrimination of sexes in these Argentinean samples. In conclusion females consistently exhibit narrower epidermal ridges than males, which may evidence a universal pattern of sexual dimorphism in this trait that can be useful in forensics in the identification of individuals.

A comparative study of topological and sex differences in fingerprint ridge density in Argentinian and Spanish population samples.

Although several studies have recently assessed sex differences in fingerprint ridge density and its variability in human populations from different origins, such a study has not been carried out yet in the Amerindian population. The goal of this study was to determine the topological and sexual differences in fingerprint ridge density (RD) in native subjects from two samples of northwestern Argentina (Jujuy province) living at different altitudes. The results were compared with those obtained from a Spanish population sample. The study was based on data from all 10 fingerprints of 393 adult Argentinian men and women, 193 from the Puna-Quebrada region (more than 2500 m above sea level) and 200 from Ramal (500 m above sea level). Ridge density was assessed for three different areas (radial, ulnar and proximal) for all 10 fingers of each subject. In both samples, significant differences between areas were obtained, so radial RD > ulnar RD > proximal RD. No significant differences were found between samples in males, while females from both samples significantly differed in the radial and proximal areas. Females have higher RD, so narrower ridges, than men, in all areas and all fingers. Application of Bayes' theorem allowed us to obtain a ridge density threshold for discrimination of sexes in Argentinian samples and the threshold for discrimination of populations between Argentinian and Spanish samples. These results can be useful for forensic use.