Arches, loops, whorls: The science (we bet you didn't know) behind a fingerprint
Just like how cheetahs and zebras acquire their spots and stripes, the intricate swirls of a fingerprint are formed by the interaction of two proteins
Ever wondered what makes a fingerprint so unique that no two patterns are alike? Just like how cheetahs and zebras acquire their spots and stripes, the intricate swirls of a fingerprint are formed by the interaction of two proteins during fetal development.
According to a study published Thursday in the peer-reviewed science journal Cell, one protein encourages formation of ridge-like patterns while the other restricts it. This colliding movement results in periodic waves of ridges that take form from three separate points on the fingertip. The three regions are - the end of the fingertip, the pad in the middle of the fingertip; and the crease between the fingertip and the middle finger joint.
A report in the British scientific journal Nature quoted co-author of the study and a developmental biologist at the UK-based University of Edinburgh, Denis Headon, who pointed out that the process behind the deployment of the molecular ingredients on the anatomy of the hand is critical in the ‘formation of arches, loops, and whorls’.
By analysing the ridges on the toes of mice and human cells grown in 3D cultures, Headon and team discovered a protein called WNT - a key component in development of hair follicles - triggers ridge formation. A molecule known as BMP impedes them.
Through simulations, the research team changed the timing, angle and location of the waves to form arches, loops and whorls.
Fingerprints are considered crucial in identification, diagnosis of certain conditions and also give grip and sensitivity to fingertips. Headon has also researched on the genes, which lay the foundation for fingerprint patterns. While most of these are also part of limb development, many lay latent during the ridge process.
Headon and his colleagues found that the cells behind the fingerprint ridges initially mirrored the trajectory of a hair follicle. However, the gene activity of ridge cells avoided integration of cells from deeper under the skin’s surface, unlike a hair follicle.
According to Marian Ros, a developmental biologist at the Institute of Biomedicine and Biotechnology of Cantabria in Santander, Spain, the findings point towards the existence of a ‘Turing reaction–diffusion system’. First proposed by mathematician Alan Turing in 1952, the theory states that a self-organising system of period waves is created by the interplay of two diffusible molecules.
Ros adds that the findings are a significant achievement in fingerprint pattern analysis as the study involves cell-culturing methods and other advanced techniques.