Genetics term was given by Bateson. W. Bateson is called father of modern genetics. Genetics is collective study of heredity & variations. Where heredity is transmission of genetic character from parent to offspring and variation is Individual of same species have some differences these are called variation.
History of researches in genetics:-
Muller-Proposed the term “Cytogenesis” (Cytology Genetics) Father of Actinobiology study the effect of radiation on living organisms.
Morgan (Father of Experimental genetics)- He experiment on drosophila & proposed various concepts. He give following terms Linkage term, theory of linkage, crossing over term, criss –cross inheritance, Linkage map on drosophila
According to gene theory; genes are linearly located on chromosome.
Garrod (Father of human genetics & Biochemical genetics). Garrod discovered first human Metabolic genetic disorder which is called alkaptonuria (black urine disease) in this disease enzyme homogentisic acid oxidase is lacking. Explain the like begets like (off-springs are similar to their parents).
Vapour fluid theory – Greek philosopher Pythagoras (500B.C) proposed this theory.
Semen theory -: This theory has given by Empedocles.
Preformation theory- According to this theory germinal (reproductive)cell contains a miniature figure of a man. According to swammerdam preformation of a miniature of man is found inside the egg is called minkin those scientists who believed in the hypothesis of swammerdam are known an ovists.
On contrary according to Harsoeker preformed miniature of man is present in sperm.A miniature of man is present in sperm he called Homunculus. Scientist who believed in Harsoeker view are called spermist.
Encasement theory:-This theory was proposed by Charles Bonnet.
Epigenesis theory:– this theory was proposed by K.Wolf. According to his view germinal cells possess an undifferentiated material.This material develops step by step (Gradually) after the fertilization .such type development is known as Epigenesis.
Pangenesis theory:- The theory of pangenesis was described by C. Darwin. This theory postulated that all part of a living body (Tissues) synthesize micro molecules. These micro molecules are known as pangenes or Gemmules. The male and female pangenes fuse together during the fertilization these are further again distributed in the various organs of the body at the time of development.
Germplasm theory:- The view was proposed by A Weisman (1886). According to him living body of an individual possess two different types of fluid material-somatoplasm and Germplasm. Somatoplasm does not participate in the formation of germinal cells (immortal) therefore variations are not transferred in to the progeny. Somatoplasm is mortal because eventually it dies.