Question

Who proposed the chromosome theory of inheritance?List the main points of this theory.

Answer 1

Chromosomes are thread like structures which are located inside the cell in the nucleus in the animal cell. The chromosomal theory of inheritance talks about how chromosomes are passed on from parents to the offsprings.

Complete answer:
Before chromosomes were visualised under microscope,father of modern genetics,Gregor Mendel started studying about heredity. Chromosomal theory of inheritance was consistent with Mendel's laws and was supported by the following observations:
i) During meiosis, same Chromosome pairs migrate as discrete structures independent of other pairs.
ii) Chromosomes from each pair are randomly sorted.
iii) Each parent synthesizes gametes containing only half of their chromosomal Material.
iv) Both male & female gametes contain an equal number of chromosomes.
v) The produced offspring contain the same numbers of chromosomes as their parents.

Let us take a close look towards chromosome theory of inheritance and how it evolved. Chromosomes were identified as the genetic material responsible for inheritance in the chromosomal theory.

Two scientists Walter Sutton & Theodore Boveri (Sutton and Boveri) independently proposed the theory of chromosomal inheritance stating that inherited traits are controlled by genes on the chromosomes or they are the vehicles of heredity.

Key points of chromosomal theory are:

Factors described by mendel are the genes that are actual physical units of heredity.
The genes are present in a linear fraction of chromosomes.
Each organism has a fixed number of chromosomes that occur in two sets known as diploid (2n).
One set is received from the male parent and another is received from the female parent.
The genes thorough chromosomes segregate and assort independently at the time of gamete formation.

Note: Law of constant chromosome was proposed by Boveri and as per this theory it states that every animal has a definite amount of chromosome number. This also suggested that equal genetic contribution is seen from each parent.