You might have often heard that 7 different people in this world can have same face structure and body shape too. Is it really possible to have 7 same faces in actual practice? It is very difficult to draw any conclusion without deep study on the base of genetics.
Each and every kind of structure, either in face or any other body parts are due to the result of phenotype and genotype. Genotype is determined by the genetic material DNA (in human) only. However, phenotype resembled can be later on affected by different types of environmental factors. Mutation can also occur which can bewilder the normal concept we have till now about the phenotype and genotype.
What is phenotype?
The morphological (physical) structure seen as an outer appearance due to the effect of genotype as well as influence of environmental factors is known as phenotype of an organism. Mutation directly affects the genotype acquired from heredity (process of transmission of physical and genetic characteristics from parents to offspring). Genotype affects phenotype.
What is genotype?
The genetic makeup or the genetic structure of an organism generally acquired from heredity, which is stored in DNA of an organism, correspondingly resembling the phenotype is known as genotype. It is the gene where mutation takes place.
Taking into the consideration of the time right when human species started to till now, evolution played vital role to change us drastically. Although from generation to generation we have evolved but we are all diversified forms of our single ancestor. The genes contained in our ancestor got mutated in different ways during cross fertilization due to which hybrid species were formed which were genetically different. During the hybridization of the species the genotype of the species go through the changes that make changes in phenotype. The genetic change makes physical change in us. The face, body structure, characters required for adaptation, etc. get modified in every filial generation during cross breeding.
The question may be raised that how was it possible to form species of different genotype to form non-sister species (species from different parents having same genotype) when there were only one maternal and one paternal form of the very species, say human. As mentioned above, the mutation plays vital role in abrupt evolution. The geographical aspects, mode of nutrition and different environmental factors bring about a change in the genetic structure of the species. Furthermore, different rays of the sun also alter the coding of DNA. It changes the genetic structure. In this way, species of different genotypes are formed.
When non-sister gametes are fertilized, new hybrid form of the species is formed which is different in both genotype and phenotype. This phenomenon continues for several thousands of years to form large diversified groups of same species, which are distributed all over the world. This is the reason we are having people all over the world having different faces and body structures. Everyone differs from each other in at least one or two genetic or physical characters. Nevertheless, we hear that two people having same face were reported. Now after getting the background of what brings about a change in the genetic and physical structure of any species, let us go deeper to find out whether it is possible to have same face by two people or not.
*In this diagram, BB, Bb and bb represent pure black eyed, hybrid black eyed and pure blue eyed respectively.
Discovered by Madhusudan Duwadi