Study of the Variability of the Main Dermatoglyphic Traits on the Distal Phalanges in Adolescents
Authors:   Irkutsk State University, Bolotov А. V. , Sadovnikova A. M. 
Published: April 2023

The work is devoted to the study of the variability of the main characteristics of the skin pattern of the fingers in boys and girls. The study involved 93 adolescents, including 52 girls and 41 boys. The dermatoglyphics of the fingers was studied according to the standard method with an assessment of the type of pattern and the overall intensity of the patterns. During the study, the following main phenotypes of digital dermatoglyphics were identified: 10L, AL, ALW, LW, 10W. Additionally, there were varieties of loop pattern: ulnar (elbow) loop - Lu; radial loop - Lr; double loop - 2L. The total intensity of the patterns was assessed by the DL delta index. In the examined group of adolescents, a study was made of the dermatoglyphic characteristics of finger patterns (type of pattern and its combinations, delta index, total scallop count, dermatoglyphic indices (finger pattern indices, pattern type indices) of Dankmeyer, Poll, Furugata and pattern intensity index), asymmetries of skin patterns and ridge count. The significance of differences between independent results obtained in the course of comparative analysis was determined using Student's t-test. The significance level was set at p<0.05. The distribution of types of patterns and their combinations on the nail phalanges of the fingers indicates that these characteristics of dermatoglyphics in girls have a simpler version compared to the dermatoglyphics of boys. The presence of pattern type W indicates a high probability that the fingerprints belong to young men, pattern type A - to girls. According to the frequency of occurrence of patterns on different fingers, a more frequent presence of arches in girls and curls in boys was revealed. The arc pattern is more often found on the second finger, but with different frequency (more often in girls), then on the third, fourth and fifth fingers. The loop pattern is more often found on the fifth, third and first fingers. Curls are more common on the fourth finger, then the second, third and first fingers in boys, and in girls on the fourth finger, then the second, first and third fingers, but with less frequency. Here it was possible to reveal a slight sexual peculiarity in the location of the curls: in boys the third finger, and in girls the first finger, but with a higher frequency in boys. The scallop count has a fairly large range of intragroup variability, especially among young men. The average values of the scallop count in young men are significantly higher, i.e. confirms the fact that this characteristic of dermatoglyphics in girls has a simpler variant (p<0.05). Asymmetry between the right and left hands in the surveyed groups of schoolchildren in this indicator was not revealed. A more pronounced phenomenon of fluctuating asymmetry of dermatoglyphic features in young men was found, manifested in such patterns as the ulnar loop and especially curls. Comparative analysis of the distribution by types of patterns and their combinations on the nail phalanges of the fingers, as well as the delta index showed that young men more often have more complex variants of these characteristics of dermatoglyphics. Therefore, a number of characteristics of the skin pattern of the fingers, such as the "arch", "ulnar loop" and "curl" phenotypes, their presence on certain fingers, as well as the level of the delta index and the asymmetry of skin patterns (ulnar loop and especially whorls) indicate that in the surveyed group of teenagers there are differences between boys and girls. The combination of these signs can be used for gender identification of a person.