It is the synthesis of the ideas of Neo Darwinians as a new theory of evolution based upon recent findings of genetics and molecular biology.
Thus, Neo-Darwinism has emerged as the mathematically based Modern Synthetic Theory of Evolution designated by Huxley (1942).
Muller, Dobzhansky, Fisher and Wright are also the main contributors.
G.L.Stebbins (1966-76) gave this theory in present form as follows : Five factors have been identified as main bases
First is gene mutation, second is chromosomal changes and 3rd is genetic recombination to cause genetic variability. These changes are then acted upon by natural selection and reproductive isolation which guide the population into adaptive channels. There are also accessory factors like gene migration and hybridization to increase the genetic variability. Lastly the chance factors (genetic drift) in small population is also relevant in the evolution of the new species.