Why do people have fingerprints?

Fingerprints are genetically influenced. Because everyone's genes are different, so are their fingerprints. However, although the formation of fingerprints is mainly influenced by heredity, there are also environmental factors. When the fetus develops in the mother's body for three to four months, the fingerprint has been formed, but the child's fingerprint will change slightly in the process of growth, and it will not be finalized until puberty is about 14 years old. In the process of skin development, although the epidermis, dermis and matrix layer all grow together, the soft subcutaneous tissue grows faster than the relatively hard epidermis, so it will generate a continuous jacking pressure on the epidermis, forcing the slow-growing epidermis to contract and collapse towards the internal tissue, and gradually bend and wrinkle, so as to reduce the pressure exerted by the subcutaneous tissue. On the one hand, it is hard to attack, on the other hand, it is forced to withdraw, which leads to uneven skin and lines. This process of bending and wrinkling fluctuates with the change of the upward pressure generated by the internal tissue, forming uneven ridges or wrinkles until the development process stops, and finally it is shaped into a fingerprint that will remain unchanged until death.

There are three basic types of fingerprints-ring, bow and spiral. It is the different directions of subcutaneous tissue pressing the epidermis of finger pulp that create these different types. Studies have shown that if someone's finger belly is tall and round, the fingerprint will be spiral. Now, scientists have been able to reproduce those common fingerprints through models, and they can also repeat the formation process of less complicated rare fingerprints.

At present, it has not been found that different people have the same fingerprint, so everyone's fingerprint is unique. Because fingerprints are everyone's unique symbol, in recent centuries, the fingerprints left by criminals at the crime scene have become an important clue for the police to pursue suspects. Nowadays, the fingerprint identification method has been computerized, which makes the identification process faster and more accurate.