Genetic mutations and types

A brief presentation about the types of genetic mutations explained with examples.

1. Mutation Venkatesh Karthikeyan Email : [email protected]

2. Definition: M utation  is a sudden,permanent change in the nucleotide sequence of the genome of an organism, virus, or extrachromosomal DNA or other genetic elements.

3. Mutagens: A n agent, such as radiation or a chemical substance, which causes genetic mutation.

4. Point Mutations: It is a single base modification Substitution is a point mutation

5. Substitution:  A  substitution  is a  mutation  that exchanges one base for another. Example: THE FAT CAT ATE THE RAT THE FAT HAT ATE THE RAT

6. Substitution: Transition mutation Transversion mutation

7. Transition mutation A  transition  is a point  mutation  that changes a purine nucleotide to another purine (A ↔ G) or a pyrimidine nucleotide to another pyrimidine (C ↔ T).

8. Transversion Mutation: Transversion refers to the substitution of a   purine  for a pyrimidine  or conversely in DNA.

9. Frameshift mutation: A  frameshift mutation   is a genetic mutation  caused by insertions or deletions of a number of nucleotides in a DNA sequence that is not divisible by three.

10. Insertion: A type of  mutation  resulting from the addition of extra nucleotides in a DNA sequence or chromosome . Example: THE FAT CAT ATE THE RAT THE FAT CAT XLW ATE THE RAT

11. Deletion: A type of  mutation  resulting from the deletion of nucleotides in a DNA sequence or chromosome. Example: THE FAT CAT ATE THE RAT THE FAT CAT ___ THE RAT

12. Mutation Detection Techniques: Single Strand Conformational Polymorphism (SSCP) Heteroduplex Analysis Conformation Sensitive Gel Electrophoresis (CSGE) Protein Truncation Test (PTT) Denaturing High Performance Liquid Chromotography (DHPLC) Ame’s test to detect mutagenicity

13. Down Syndrome Chromosome 21 does not separate correctly . They have 47 chromosomes in stead of 46 . Children with Down Syndrome develop slower, may have heart and stomach illnesses and vary greatly in their degree of inteligence .

14. Cri-du-chat Deletion of material on 5 th chromosome Characterized by the cat-like cry made by cri-du-chat babies Varied levels of metal handicaps

15. M̀hgòi 