'Jumping genes' ormovable genetic elements were discovered by 'Barbara McClintock' (1902-92) in maize. These 'controlling elements' could move from one location to another on the chromosome.
Barbara McClintock got the Nobel Prize for these genetic elements (Ds=Dissociation gene, $\mathrm{Ac}=$ Association gene) which can jump to any chromosome from their original location on chromosome.
The term'transposon' was introduced by R W Hedges and A E Jacob (1974) to these genetic element (jumping gene)Hugo de Vries introduced the term'mutation', in connection with the studies on Oenothera lamarckiana (evening primrose). His theory is known as mutation theory.T H Morgan proposed the 'gene theory' (linkage of genes) and crossing over.Gregor Johann Mendel (1822-1884) is known as the 'father of genetics'. The first scientific study leading to formulation of laws of inheritance was carried out by Mendel.