How unique fingerprints evolve

In case you ever wondered about you unique fingerprints!

"... produced during fetal development by waves of tiny ridges that form on the fingertip, spread and then collide with each other — similar to the process that gives a zebra its stripes, or a cheetah its spots. ...

researchers found that the interplay between two proteins — one that stimulates ridge formation, and another that inhibits it — produces periodic waves of ridges that emerge from three distinct regions on the fingertip.

The precise locations of these regions and the collisions between the waves yields the unique pattern of a fingerprint. ...
Last year, [researchers] published work describing the genes that influence fingerprint patterns, many of which are involved in limb development. ...

The analyses supported the presence of a ‘Turing reaction–diffusion system’, which can be created when a molecule that activates a developmental process stimulates both itself and an inhibitory molecule. The result is a self-organizing system that creates periodic patterns ...

Such systems were proposed by mathematician Alan Turing in 1952 as a chemical explanation for developmental processes such as the arrangement of leaves on a plant or tentacles on the small aquatic organisms called hydras. Since then, Turing reaction–diffusion mechanisms have been described as instrumental in establishing a wide variety of familiar biological sights, including the brightly coloured scales of some tropical fish, and feather patterns in birds. ..."

From the highlights and abstract:

"Highlights

• Early fingerprint ridges are epithelial buds molecularly analogous to hair placodes

• Fingerprint ridges do not recruit mesenchymal cells or express late hair follicle markers

• Interacting WNT and BMP signaling defines the spacing interval between ridges

• Ridge initiations from anatomically variable sites determine fingerprint pattern type

Summary

Fingerprints are complex and individually unique patterns in the skin. Established prenatally, the molecular and cellular mechanisms that guide fingerprint ridge formation and their intricate arrangements are unknown. Here we show that fingerprint ridges are epithelial structures that undergo a truncated hair follicle developmental program and fail to recruit a mesenchymal condensate. Their spatial pattern is established by a Turing reaction-diffusion system, based on signaling between EDAR, WNT, and antagonistic BMP pathways. These signals resolve epithelial growth into bands of focalized proliferation under a precociously differentiated suprabasal layer. Ridge formation occurs as a set of waves spreading from variable initiation sites defined by the local signaling environments and anatomical intricacies of the digit, with the propagation and meeting of these waves determining the type of pattern that forms. Relying on a dynamic patterning system triggered at spatially distinct sites generates the characteristic types and unending variation of human fingerprint patterns."

How fingerprints get their one-of-a-kind swirls The intricate patterns are created during fetal development when fine ridges on the skin form and crash into each other.

The developmental basis of fingerprint pattern formation and variation (open access)

Graphical abstract