Question

The linked dominant gene hypothesis was proposed by

Answer 1

George Beadle and Edward Tatum.

Answer 2

The linked dominant gene hypothesis or dominance hypothesis in heterosis was proposed by Davenport(1908), Bruce(1910) and Keeble & Pellew(1910).

In this hypothesis, they stated that a gene is a combination of more than one alleles, among which some are dominant on other one. That means one is dominant and other is recessive, a combination of them a heterozygous gene will only produce the characteristics of the dominant alleles, the recessive allele will not induce any characters. The phenotype of a homozygous dominant gene and heteozygous gene will be the exact same, only the genotype of them will be different. The mix of these two gene in next generation also will not show a newly generated character with the effect of the two allele.

For example, If allele T generates long stem plants and t generates short stem plants; if T is dominant over t allele;

TT and Tt will generate long stem plants and tt will generate short stem plants.