Question

The term “linkage” was coined by
(a) W. Sutton
(b) T. H. Morgan
(c) T. Boveri
(d) G. Mendel

Answer 1

Hint: Upon carrying out several dihybrid crosses in the Drosophila to study the genes that were sex-linked, it was described that there is a physical association between some genes that are present on a chromosome.

Complete answer: Morgan coined the term “linkage” by performing dihybrid cross experiments on the fruit-fly Drosophila. While crossing a set of characteristics he observed that two genes do not always segregate as said by the Mendel. He found that if two genes are present on the same chromosome then in the next generation there is a high probability that the parental combination will be found more in comparison to the non-parental combination.

Additional information:
Morgan crossed a purebred white-eyed male fruit-fly with the purebred red-eyed female fruit-fly. In this cross, the result obtained was in accordance with Mendel’s laws of inheritance because the F₁ progeny were having red eyes. But, when F₁ generation was self-crossed, the ratio of red-eyed to white-eyed progeny was 3:1 and there was no white-eyed female in the F₁ generation and then Morgan thought that such a result might be due to linkage between the two traits.
So, the correct answer is ‘T. H. Morgan’.

Note: In genetics, the linkage is the tendency of genes to get inherited together during meiosis of the sexual reproduction, when the genes are located closely on a chromosome. In such cases, the extent of recombination decreases between the two genes, and more parental type combinations are seen in the progenies of the next generation.