Biology · Principles of Inheritance and Variation · NEET
Walter Sutton and Theodor Boveri proposed it (around 1902). Sutton joined the idea of chromosome movement in meiosis with Mendel's rules and named it the chromosomal theory of inheritance. So for the word 'proposed', the answer is Sutton and Boveri.
Thomas Hunt Morgan verified (proved) it by experiments. Sutton and Boveri only argued the theory using observations; they did no crossing experiments. Morgan tested it with real breeding experiments on fruit flies. NEET loves this exact split: 'proposed = Sutton and Boveri', 'verified = Morgan'.
Because it places Mendel's factors (genes) ON the chromosomes. Before this, no one knew where genes physically sat. Scientists saw chromosomes double and separate before cell division, and this behaviour matched how genes behave. So genes were said to be carried by chromosomes, giving the theory its name.
In meiosis, chromosomes exist in pairs and the two members of a pair separate into different gametes. Mendel's factors (alleles) also exist in pairs and separate into different gametes (Law of Segregation). Sutton said the pairing and separation of a chromosome pair causes the segregation of the pair of factors it carries. This matching behaviour is the whole basis of the theory.
Drosophila melanogaster is easy to grow on simple synthetic medium, completes its life cycle in about two weeks, and one mating gives many offspring. Males and females are easy to tell apart, and it shows many visible hereditary variations under a low-power microscope. These features made it perfect for verifying the theory.
Before. In 1900, three scientists (de Vries, Correns and von Tschermak) independently rediscovered Mendel's work. Around the same time, better microscopes let scientists watch chromosomes double and divide. These two events together led Sutton and Boveri to propose the chromosomal theory soon after.
Experimental verification of the chromosomal theory of inheritance was done by
Frequency of recombination between gene pairs on some chromosome as a measure of the distance between genes to map their position on chromosome, was used for the first time by
Try the real previous-year questions from this chapter — each with the answer and a full solution.
It was proposed around 1902 by Walter Sutton and Theodor Boveri, soon after Mendel's work was rediscovered in 1900 and after chromosomes were seen doubling and dividing during cell division.
Genes (Mendel's factors) are located on chromosomes, and the pairing and separation of chromosomes during meiosis explains how the pairs of factors segregate into gametes.
No. Mendel's laws describe how factors behave (dominance, segregation, independent assortment). The chromosomal theory explains WHERE those factors are and WHY they behave that way, by placing genes on chromosomes.
Drosophila melanogaster, the fruit fly. It was chosen because it breeds fast (about two weeks per life cycle), gives many offspring, and shows many visible variations.
Sutton united the knowledge of chromosome segregation in meiosis with Mendelian principles and named this combined idea the chromosomal theory of inheritance.
