Question

21. Does a mutation always, rarely, or never affect the traits of an organism? Explain. Include a definition of mutation in your answer and explain how it affects phenotypes.

Answer 1

Definition

Mutation is the process of alteration of a gene or chrornosome and its product. It is a sudden genetic change. Some mutations are heritable (Germinal) whereas, some mutations are not heritable (somatic). Germinal mutation plays an important role in evolution.

Effects of Mutation of phenotype

1. Forward mutation- Wild type become mutant type
2. Reverse mutation- Mutant type becomes wild type
3. Loss-of-function mutations- most often, loss-of-function mutations are recessive
4. Gain-of-function mutations- most often, loss-of-function mutations are dominant
5. A harmful mutation reduce the fitness of the organism
6. Beneficial mutation- increace the fitness of the organism
7. Neutral mutaion - have no effect on phenotype
8. Non-sense mutation- adverse effect on phenotype Eg may cause diseases such as  congenital adrenal hyperplasia
9. Silent mutation- have no effect on phenotype
10. Missense mutation- have little or no effect on phenotype
11. Germline mutation- Heritable, affect following generation also
12. Somatic mutation- Not heritable.Do not affect following generations