CHAPTER 3. INHERITANCE AND VARIATION

Write a note on chromosomal theory of inheritance?

Ans.:Sutton and Boveri proposed following postulates -

1) Since the sperm and egg cell provide the only bridge from generation to generation, all hereditary characters must be present in them.

2) Sperm cell loses all its cytoplasm in maturation process since the sperm contributes equally in the heredity, the factors must be present in the nucleus.

3) Chromosomes are found in pairs.

4) The union of sperm and ovum with haploid set of chromosomes, reestablishes for the new organism the whole number of chromosomes previously seen in the body cells of parent organism.

5) During cell division, chromosomes divide accurately. It provides idea that genes are carried on chromosomes.

6) Chromosomes show segregation during meiosis. It means that members of each pair separate and go to different cells. (Mendelian factors show same process)

7) All the members of chromosome pair segregate independently of other chromosomes.