The dominant gene and the recessive gene can be defined as the DNA sequence that allows certain people to inherit some physical characteristics and traits. They are responsible for carrying the genetic information that both men and women can pass on to their children.
The dominant gene is one that is present in one phenotype and appears twice (when it is made up of one copy corresponding to each parent, which is called a homozygous combination) or in a single dose (called heterozygosity).
The physical characteristics that an individual will have, whether animal or plant, is what is known as a phenotype. In the case of humans, the phenotype corresponds to the color of the skin, the color of the hair, the color of the eyes, the height, the shape of the earlobe, the shape of the nose, etc. The phenotype is the appearance of the individual on the outside.
The genotype is the constitution of the individual from the point of view of their genetics, it corresponds to all the information that is in their DNA and that was inherited from their parents. The genotype largely determines the phenotype, however, sometimes the phenotype is expressed or not according to the characteristics of the environment.
The information contained in DNA is organized into chromosomes, which in turn contain fragments with specific information called genes that are located at certain sites on the chromosome called locus, each gene is related to the quality of the individual. Genes found on the X and Y sex chromosomes carry sex-related characteristics.
When individuals reproduce, they contribute half of their genetic information to the new being. This happens because the chromosomes are in pairs. During reproduction, the pairs separate to form the gametes or reproductive cells, which are the eggs and the sperm. At the time of separation, the chromosomes are found randomly, which means that the genetic information is different between these cells.
Once the chromosomes are assembled in pairs to form the new individual, it happens that there may be different information from each parent about the same trait. Take for example the color of the eyes, if you receive the gene from the father for the color blue and the gene from the mother for the color brown, it will happen that the dominant gene will be expressed, which in this case is brown eyes. From a phenotype point of view, the new being will have brown eyes, but its genotype has information for brown eyes and blue eyes.
In this way, when there are two genes for the same information, there will be one that will have the ability to cover the other and express itself, it is the dominant gene.
The transmission of characters between parental organisms and their offspring is as complex as it is fascinating. The first person to conduct analytical research on this matter was the monk Gregor Mendel in the 19th century, not knowing what a gene was.
