Research already conducted has established a direct link between the characteristic features of dermatoglyphs on the fingertips and toes and activity in the left and right hemispheres of the brain's cortex. Just as mental activity is divided between the left and right hemispheres, one of which dominates, it can also be proposed that dermatoglyphs on either the left or right hand or foot will have dominance over those of the other limb.
Our current work has investigated the fundamental types of papillary patterns on the fingertips and toes, the dermatoglyphic phenotype and asymmetry between patterns. The subjects were students from the Faculty of Sports in the Institute of Education and Social Sciences and from the Institute of Life Sciences, both at North Caucasus Federal University, and from the Olympic Reserve School in the city of Stavropol.
The following dermatoglyphic patterns have been noted in the course of our research: the Arch (A), without a triradius; the Loop (L), with a single triradius; and the Whorl (W), with at least two triradii.
In terms of increasing evolutionary complexity, the Arch (A) is the most basic pattern, the Loop (L) is of medium complexity, and the Whorl (W) is the most advanced. This tallies with the findings of a great number of both Russian and international academic investigations. Among them is I.S. Guseva (1986), who noted that subjects with arch-type patterns on their fingertips had the lowest level of tactile sensitivity, while those with double-delta patterns had the highest.
The relative complexity of the patterns can be measured according to the following scale: the Arch (A) is a Level 1 pattern, the Loop (L) is Level 2, and the Whorl W) is Level 3, with complexity increasing from Level 1 to Level 3. In our research dermatoglyphs on the left and right hands and feet were evaluated separately and according to this scale.
Chart 1 depicts the pattern asymmetry of one of the athletes tested. The Y-axis shows the scale of pattern complexity, and each of his fingertips is displayed along the X-axis. The chart demonstrates that he has double-delta patterns on the right hand and single deltas on the left. In this case Level 3 patterns have dominance over Level 2 patterns on all five fingertips.
Chart 1. Papillary Ridge Pattern Asymmetry of Left and Right Fingertips
A similar analysis was made of the same athlete's toes (Chart 2).
Chart 2. Papillary Ridge Pattern Symmetry of Toes of Left and Right Feet
Analysis of the data gathered established that in the majority of cases it was possible to determine one hand and foot with a level of pattern complexity greater than that of the opposite limb. The hand with the more complex pattern was accordingly named the "progressive hand”, and the foot with the more complex pattern on its toes was named the "progressive foot”, while the hand with the less complex patterns on its fingers was named the "regressive hand” and the foot with the less complex patterns on its toes was named the "regressive foot”. In the case of this particular athlete the right hand was the progressive hand and the left hand was the regressive hand (Chart 1), and the right foot and left foot were respectively the progressive and regressive feet (Chart 2).
The terms "neutral hand” and "neutral foot” were used to describe cases when symmetrical dermatoglyphic patterns were observed (Charts 3 and 4).
Chart 3. Papillary Ridge Pattern Symmetry of Left and Right Fingertips
Chart 4. Papillary Ridge Pattern Symmetry of Toes of Left and Right Feet
Cases when opposing hands and feet have mixed patterns of differing complexity (Chart 5) will require more detailed research. Limbs with these types of distribution of dermatoglyphic patterns were referred to as "conflicting hands” and "conflicting feet”.
Chart 5. Pattern Asymmetry of Left and Right Hands with Mixed Domination
The data gathered will make it possible to evaluate dermatoglyphic patterns on the fingertips and toes in a new light, and also open new possibilities in research into domination in the dermatoglyphic phenotype.
Published by: Литвинова Л.В. ИЗУЧЕНИЕ СИММЕТРИИ И АСИММЕТРИИ ДЕРМАТОГЛИФОВ ПАЛЬЦЕВ РУК И НОГ // Материалы V Международной студенческой электронной научной конференции «Студенческий научный форум»
URL: <a href="http://www.scienceforum.ru/2014/2/6271">www.scienceforum.ru/2014/2/6271</a> (дата обращения: 20.02.2014).</p>