Who discovered that the behaviour of chromosomes was parallel to the…

The correct answer is Option (1) → Sutton and Boveri

Option (1) Sutton and Boveri — Correct. Walter Sutton and Theodore Boveri saw that chromosomes, like Mendel’s factors, occur in pairs and separate at gamete formation. They joined the movement of chromosomes with Mendel’s principles, and this became the chromosomal theory of inheritance.

Option (2) de Vries and Correns — Incorrect. In 1900 de Vries, Correns and von Tschermak rediscovered Mendel’s results independently. They did not link genes with chromosomes.

Option (3) Mendel — Incorrect. Mendel gave the laws of inheritance from his work on pea plants. He called the units of inheritance “factors” and knew nothing about chromosomes.

Option (4) Thomas Hunt Morgan — Incorrect. Morgan worked on the fruit fly Drosophila and proved the chromosomal theory by experiment. He also found linkage and recombination. The parallel itself was first noted by Sutton and Boveri.

Note: A similar question was also asked in CUET (UG) 2023 on 30-05-2023 (Slot 1).

NCERT Extract:
Chromosomal Theory of Inheritance – “… In 1900, three Scientists (de Vries, Correns and von Tschermak) independently rediscovered Mendel’s results on the inheritance of characters. Also, by this time due to advancements in microscopy that were taking place, scientists were able to carefully observe cell division. This led to the discovery of structures in the nucleus that appeared to double and divide just before each cell division. These were called chromosomes (colored bodies, as they were visualised by staining). By 1902, the chromosome movement during meiosis had been worked out. Walter Sutton and Theodore Boveri noted that the behaviour of chromosomes was parallel to the behaviour of genes and used chromosome movement (Figure 4.8) to explain Mendel’s laws (Table 4.3).”

Figure 4.8 Meiosis and germ cell formation in a cell with four chromosomes. Can you see how chromosomes segregate when germ cells are formed?