Question

What is the correct sequence of the following events?
1) Formation of the chromosome theory of heredity.
2) Experiment which proved that DNA is the hereditary material
3) Mendel’s law of inheritance discovery
A) 1,3 and 2
B) 1, 2 and 3
C) 3,1 and 2
D) 2, 1 and 3

Answer 1

Hint: During the mid of $19^{th}$ century that headway was made in the understanding of inheritance. He conducted the experiment on a garden pea plant and took seven years and finally, proposed the law of inheritance.

Complete step-by-step answer:
In 1902, the movement of chromosomes during the meiosis had been worked out. The two scientists Walter Sutton and Theodore Boveri noted the behaviour of chromosomes and behaviour of genes is parallel to each other. They used the movement of the chromosome to explain Mendel’s laws. They state that the pairing of a pair of chromosomes and separation of a pair of chromosomes would lead to the segregation of a pair of factors they carried. The Mendelian principles combined with the knowledge of chromosomal segregation by Sutton. This is called the chromosomal theory of inheritance. This theory is credited to paper by Walter Sutton in 1902 and 1903. During the same period of time, Theodore Boveri worked independently.
The undeniable proof that DNA is the genetic material came from the experiments of Alfred Hershey and Martha Chase in 1952. They worked with viruses that infect bacteria called bacteriophages. They worked to find out whether it was protein or DNA from the viruses that entered the bacteria. The bacteriophages attach to the bacterial cell and its genetic material into the bacterial cell. Now the bacterial cell treats the viral genetic material as its own and subsequently manufactures more virus particles.
Gregor Mendel conducted hybridisation experiments for seven years (1856-1863) on the garden pea. After that, he proposed the law of inheritance in living organisms. He observed that genes come in pairs and inherited independently from each parent. The law of dominance, the law of segregation and law of independent assortment are the three laws he proposed.

Hence, the correct answer is option C.

Note: The work of Mendel and others who followed him gave us an idea of the inheritance pattern. The ‘factors’ represent the genetic basis of inheritance. To understand the structure of genetic material and also the structural basis of phenotype and genotype, these topics become the focus of attention in biology for the next century.