Gene theory

In Gene theory, the gene is considered as the fundamental, physical, and functional unit of heredity. It is located on the chromosome and contains DNA. The gene stores the genetic code, i.e. a sequence of nucleotides that determines the structure of a protein or RNA. A gene is a unit of heredity because it is transmitted across generations. It is through which the phenotypic trait of an organism is based upon.

Gregor Johann Mendel was one of the main pioneers that established the science of genetics. As such, he is regarded as the father of the said field. He was able to determine the occurrence of unit factors that were passed down from one generation to the next. He described these unit factors as occurring in pairs. One of the pairs will be dominant over the other. He formulated the Mendelian laws to elucidate how heredity occurs.

These laws include Law of Segregation, Law of Independent Assortment, and Law of Dominance. The inheritance pattern that follows these laws is referred to as Mendelian inheritance. Conversely, an inheritance pattern that does not conform to these laws is described as Non-Mendelian.