The field of genetics and evolution are extensively interlinked. Each species in the living world are maintaining some distinct characters. One of such distinct character in higher organisms is the number of chromosomes and different genes responsible for characters are maintained by such organisms during passage of genetic characters from one generation to the other. This number and genetic combination is maintained due to two different types of cell divisions duly involved in this process. Reductional division (or meiosis) brings the chromosome number to half while forming germ cells (Gametes). After union of male and female gametes the newly developed organism retains the chromosome number as that of the parent genome.

Organisms intend to retain all the genetic spepcialities of their parents with absolute identity. During some cases gene sequences recombine to bring variations. Some genes may express their specialities and some of the recessive parter of an allele remain down the scene.

On the basis of the molecular basis of genetics we can say that Nucleic Acids (either DNA or RNA) act as the base template of genes. They are capable enough in issuing codes of particular types for the synthesis of protein or any other segment of RNA. Proteins regulate variations of characters and life processes. Hormones and enzymes are also mostly pprotein in nature. Such a building block of life is determined by combination of genes.