A group of morphological, physical and physiological aspects / characteristics of a given living organism. Here is the definition of the term phenotype. With Greek origin, the word phenotype is the combination of two other “pheno” , which means evident bright, and “typos” , which is translated as a characteristic.
Thus, phenotype compression expresses the representation of a genotype. That is, the proteins that the genotype encodes are decisive to originate the phenotypic characteristics.
The functioning of genes in conjunction with the environment is a result of the phenotype, which can be modified frequently. That is, a genotype is impossible to change. However, the phenotype can change.
Proof of this is human skin. If a person whose genotype is for fair skin, for example, frequently exposes himself to the sun, this will cause the production of melanin to be triggered in his body. This substance has the purpose of protecting human skin from the sun’s rays and, with that, it will tend to acquire a more pigmented, dark color.
In such a way that the genotype of a person like the one mentioned above will always be the same: fair skin. However, its phenotype, which is more easily noticed, visible, will change.
However, people with excessively light skin, in general, have recessivity for several genes that encrypt this characteristic. Thus, because the recessive genes encrypt defective proteins, people with skin whose color is very light end up becoming much more reddish than brunettes, if they are frequently exposed to sunlight.
This effect occurs due to the very low production of melanin or even the non-production of this substance, which would act on the skin’s pigmentation as a form of defense against the sun’s rays. Thus, the red tint of the skin is the irritation caused by excessive exposure to the sun.
Other relevant considerations
In addition to the color of the skin, a human being can have his phenotype altered quite frequently in other aspects. Similar example are thin people who, from the practice of physical exercises, start to obtain a higher content of muscle mass.
It is worth mentioning yet another example, which are people with blond hair who can leave them with dark coloring, through the application of paints. And the same procedure can be done in reverse.
However, the modified phenotypes of a given human being cannot be inherited by their descendants, since only the genotypic characteristics can be perpetuated.