Fingerprints: All human beings have them from birth and throughout life they involuntarily imprint them in various places. Anatomically, they constitute the structure formed at the fingertips by the papillary ridges. (sweat secretion glands located in the dermis).
In dialogue with the UNQ science news agencythe criminalist María Eugenia Petrini, deputy director of the Attorney General’s forensic laboratory, explains that fingerprints are particular formations found on the third phalanx of the fingers. “These formations are composed of ridges and papillary sulci that form a particular design or pattern. In other words, fundamental type”.
This structure is unique to each person and, once defined, at the 19th week of gestation, it remains unchanged throughout life. They just don’t change over time.
For example, if the impression of the ridges and papillary sulci is taken from an individual during his childhood and compared with that obtained when he reaches adulthood, it will be observed, irrespective of typical growth changes such as size, that the impressions they remain identical.
Other features are that they are immutable. That is, they cannot be modified: in case of injury, if it is mild, the tissue will regenerate without causing any change.
Why does each person have a different footprint?
As the experts explain, the imprint is defined by a genetic and physical component, based on the result of folds generated by the action of non-linear elastic force fields, which are produced in the basal layer of cells that exists between the dermis and the epidermis during gestational development. This implies that traits are defined before birth.
Even monozygotic twins – those that have the same genome because they are produced from the splitting in two of a single egg fertilized by a single sperm – have different fingerprints.
“It is assumed that fingerprints are influenced by the same factors that can influence a developing baby, as ridges begin to form between the third and fourth month of intrauterine life, when that cellular organism ends up being the baby.” assures Petrini. And he adds that “the different conditions that can affect in some way this pregnancy that this being is having, also affect its entire structure. And fingerprints are not exempt from this, so each individual has their own fingerprint.
What are worth for?
There are several theories about the function of fingerprints. According to research carried out by biologist Roland Ennos, from the University of Hull, UK, Fingerprints provide human grip. In that sense, they can help grip surfaces in wet conditions, similar to car tire tracks. In this way, hands are prevented from slipping on a surface.
Among the scientific community there is also the theory that could help play. Fingers contain four types of mechanoreceptors or cells that respond to stimulation (such as touch). According to Georges Debrégeas, biologist at the Sorbonne University in Paristhese mechanoreceptors are very sensitive to small vibrations and therefore contribute to the finger tips having their characteristic sensitivity.
Social and scientific uses
Fingerprints deposited on surfaces touched or manipulated, as they have a unique character for each person, are an individual identification element. In that regard, not only do they play an important role in the investigation of certain crimes, but their role in everyday life becomes increasingly important. For example, among the various options offered by the cell phone to unlock it, one of the most used is the fingerprint, an individual feature that serves to prevent other people from using the device. It is also common to facilitate access to restricted areas of buildings for certain people, or in bank account operations.
On the scientific side, Fingerprinting studies fingerprints with the aim of identifying the subject who commits a criminal act. In addition, you can also link a suspect to the place where the crime was committed or the items used to carry it out. Sometimes it has a very high probative force that can change the course of a criminal trial.
“From a criminal point of view, these are elements that will serve the purposes of human identification. In other words, they serve to give identity”, says the expert. And it details that, as each individual has its own papillary trait, the possibility of identifying a trait in relation to an individual gives the possibility of establishing an indubitable identity. That is, it can be said with complete certainty that this trait corresponds to that person”.
In Argentina, for example, fingerprints are collected as a method of identification associated with a National Identity Card. It is this quality that makes them so valuable for criminal investigations.
An Argentine who left his mark
Who discovered that a fingerprint was a valid method of proving a person’s guilt in murder? The world’s first system was created in Argentina in 1891 by the anthropologist Juan Vucetic. To start the procedure, in September of that year, the fingerprints of 23 people arrested for having committed various crimes in the country were collected. As early as 1892, it was agreed that this technique would be used to investigate murders and register people with a criminal record.
Thanks to this regulation, after a few months, it was possible to identify a woman who had killed her two daughters in the city of Necochea. It was the children of a woman named Francisca Rojas who were murdered, and she herself blamed a man she had rejected as a husband. The officers were unable to extract a confession from the suspect, even subjecting him to torture, so they began to investigate thoroughly and found a bloody footprint on a door. When comparing him, they discovered that the murderer was none other than the mother; who, before the evidence, ended up confessing.
The police soon officially adopted the Argentine Dactyloscopic System, as it later became known, making the country the first to rely solely on fingerprints as a method of identification. At the beginning of the 20th century, Vucetich’s system began to spread around the world.