Diversity of human lip prints: a collaborative study of ethnically distinct world populations

Background: Cheiloscopy is a comparatively recent counterpart to the long established dactyloscopic studies. Ethnic variability of these lip groove patterns has not yet been explored. Aim: This study was a collaborative effort aimed at establishing cheiloscopic variations amongst modern human populations from four geographically and culturally far removed nations: India, Saudi Arabia, Spain and Nigeria. Subjects and methods: Lip prints from a total of 754 subjects were collected and each was divided into four equal quadrants. The patterns were classified into six regular types (A?F), while some patterns which could not be fitted into the regular ones were segregated into G groups (G-0, G-1, G-2). Furthermore, co-dominance of more than one pattern type in a single quadrant forced us to identify the combination (COM, G-COM) patterns. Results and conclusion: The remarkable feature noted after compilation of the data included pattern C (a bifurcate/branched prototype extending the entire height of the lip) being a frequent feature of the lips of all the populations studied, save for the Nigerian population in which it was completely absent and which showed a tendency for pattern A (a vertical linear groove) and a significantly higher susceptibility for combination (COM) patterns. Chi-square test and correspondence analysis applied to the frequency of patterns appearing in the defined topographical areas indicated a significant variation for the populations studied