Genes are nothing more than the small particles in our bodies that carry genetic material, that is, our DNA and dioxiribonucleic acid. These are responsible for the production of the protein that determines and transmits hereditary characters.
Both dominant and recessive genes are active, the difference between them being found in the protein produced by the recessive gene, causing it to have different activities in the cell.
With that, we can conclude that the genes carry some genetic characteristics, being able to be the dominant characteristics and the recessive characteristics. While those are expressed by homozygous and heterozygous beings, these are found only in homozygotes.
Dominant genes vs. recessive genes
Hereditary characteristics are determined by means of the dominant genes, even in the absence of the dominant allele. These are classified as homozygous dominant – pure – which is represented by the capital letters AA, BB and VV, and in heterozygous – hybrid – which is represented by a capital letter and a lower case letter Aa, Bb and Vv.
The recessive genes, in turn, are those responsible for the production of proteins that are considered defective. These characteristics of the recessive genes do not appear expressed in the heterozygous state. This will produce its characteristic only when the allele is present in the two pairs of homologous chromosomes. It manifests itself only in the absence of the opposite dominant gene.
The recessive genes
Recessive genes are usually linked to characteristics such as colors, but they also characterize syndromes and diseases caused by abnormal recessive genes. As an example, we can mention color blindness, albinism, myopia and hemophilia.
As an example of the characteristics of the recessive genes, we can mention blond and red hair, straight hair, blue, green eyes, being left-handed or right-handed, has a negative blood type, has myopia, among others.
The dominant genes
Among the characteristics carried by the dominant genes, we can mention the aquiline nose, dislocated lobe of the ear, chin with dimple and protract, thick lips, dark hair, baldness, dark eyes, ability to curl the tongue, curved little finger and bent thumb. These are also related to some diseases like polydactyly, Huntington’s disease and von Hippel’s disease.
In the mid-nineteenth century, nothing was known about the mechanisms of heredity, and no scientific explanation for the similarity between parents and children, plants and animals has yet been presented. Mendel, however, became interested in this subject in 1865, beginning to carry out experiments with peas. Through this experiment and the crosses carried out, Mendel was able to prove the existence of these genes that determine the characteristics of an individual, a plant or an animal.