Chapter 42, Problem 1TC

Summary Introduction

To determine:

The reason why there is no contribution from father in the case of inheritance of mitochondrial mutations from mother to offsprings.

Introduction:

Genes are the hereditary material that carries the genetic information from parents to offsprings. They code for proteins which are their real products. Any change especially the disturbance in the genetic machinery causes a change and mainly deformity in the organism in which there is a change in the genes.

Explanation of Solution

Mutations are the change in the genetic machinery of an organism. They are inherited from one generation to the other. They generally result in damage and are maximally harmful and very rarely useful. There are many types of mutations like the frame shift mutation, point mutation, addition, deletion, inversion, insertion mutations and some others.

The male and female gametes are haploid that is both have single set of chromosomes. In the process of fertilization there is fusion of male and female gametes. During the fertilization process, there is donation of the pronucleus of sperm which also contains the genetic material of father to the offsprings. So the parts of the cytoplasm are definitely of mother.

It is a very well known fact that mitochondria are present in the cytoplasm of a cell. As the contribution of cytoplasm is of mother and father’s contribution is only of pronucleus and not of cytoplasm, so it is clear that there will be no contribution of father if there is a mutation in the genes of mitochondria and it will be the contribution of mother.

Conclusion

The reason why there is no contribution from father in the case of inheritance of mitochondrial mutations from mother to offsprings is that cytoplasm is from the mother and mitochondria is present in cytoplasm and not in the nucleus in a cell.