Question

Give an example of 5 different types of Gene mutations

Answer 1

Gene mutation is defined as the changes which are occuring in the sequence of nucleotide that is gene.
Types of gene mutation are
1. Base substitution mutation - when there is a change in the base
It is of 2 types
1. Transition mutation- the mutation in which one purine( Adenine or Guanine) is substituted for another purine. Or one pyrimidine(cytosine or thymine) is substituted for another pyrimidine.
2. Transversion Mutation- The mutation by which a purine base( Adenine or Guanine) is substituted with a pyrimidine base(Cytosine or Thymine).
Example for Base Substitution Mutation is
Color Blindness: in our eyes we have various protein which are responsible for us to identify the colors like blue, green and red. If substitution mutation occured in any protein that codes for any of these colour would lead to the condition of color blindness.

.Frame Shift Mutation- It is the mutation which will change the gene reading frame due to deletion or insertion of base.
2. Deletion Mutation- The mutation by which a single base is removed and the number of DNA bases is changed.
Example- Cystic Fibrosis as the gene phenylalanine is deleted.

3. Insertion mutation- The mutation in which there is addition of piece of DNA thereby changing the no of DNA bases.
Example- Beta thalassemia.

4. Missense Mutation - The mutation in which the one codon that will code for specific amino acid is changed to the codon for another amino acid.
Example- The codon, CGT is mutated for the codon CTT. so in this case, Guanine is replaced by Thymine. Thus the protein is changed as the unmutated codon will code for arginine but now leucine has replaced it.

5. Nonsense Mutation- In this point mutation, the codon will be changed to the stop codon which will result in creation of non functional protein.
Example- The DNA codon ATC when transcribed into mRNA is mutated to produce UAG which is a stop codon thus the protein is non functional.