Question

Lyon’s hypothesis is associated with
a. Number of Barr bodies
b. Genetic compatibility
c. Genetic incompatibility
d. Centromere position

Answer 1

Lyon’s hypothesis states that in cells with multiple X chromosomes but one is inactivated during mammalian embryogenesis.

Complete step- by- step answer:
Let’s discuss the above option and find the correct answer.
- The number of Barr bodies can be seen in the Interphase and it is always one less than the total number of X chromosomes. A Barr body is one inactive X chromosome in a cell that is inactive in the process known as Lyonization. Barr bodies are found in the nucleus of neutrophils.
- Genetic compatibility is the idea of matching the relationship of the couples established on their biological compatibility. This idea of genetic compatibility was given by Claus Wedekind through his experiment.
- Genetic incompatibility can take place when there is hybridization in populations. When the two populations belong to the same ancestor and are isolated from each other. These types of changes result in the evolutionary changes within the populations. The model of the evolution of genetic incompatibility was introduced by Dobzhansky and Muller.
- Centromere position is the position on the chromosome at its centre and it can also vary depending on the position of the chromosome. It can create the long and short arm of the chromosome as it is placed at the centre. Its function is to link the two sister chromatids. The main role of the centromere is to function as the place for a gathering of kinetochores.
Hence, the correct option is A.

Note: Lyon’s hypothesis is also known as Dosage Compensation and is active from 1961. Lyonization usually means X-inactivation.