Gene mutation and its types
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Transcript of Gene mutation and its types
GENE MUTATION & ITS TYPES
Presented by: CS KAZIPYO15MSCGPB001 III SemesterM.Sc (Ag) Genetics & Plant Breeding
HOW DO MUTATION HOW DO MUTATION OCCUROCCUR
• Mutations may be natural or induced and may be occur at chromosome level or at gene or molecular level
• Spontaneous mutation is due to natural causes like errors in DNA application.
• Induced mutation is caused by artificial agents called mutagens (Physical radiation or Chemical compound).
TYPES OF GENE MUTATION
Point Mutation Substitution Insertion Deletion Frameshift
Point Mutation
• Missense Mutation: DNA → RNA → Protein (Change) (Change) (Change)
• Same/Silent Mutation: DNA → RNA → Protein (Change) (Change) (No Change)
• Non-Sense Mutation: DNA → RNA → Protein (Change) (Change) ( Stop)
• Missense Mutation:Change in nucleotide sequence brings different types of protein.
• Same/Silent Mutation:Change in nucleotide sequence brings no change in protein type. It is due to degeneracy of genetic.
• Non-Sense Mutation:Change in nucleotide sequence brings non-sense codon (UAA, UAG, UGA) at a new position in the mRNA as a result, protein synthesis adversely stops.
2. Base Substitution• Replacement of one base pair by another pair
in the DNA is known as base substitution.i) Transition:
Purine Purine Purine Purine
→ or →
→ or → Pyrimidine Pyrimidine Pyrimidine Pyrimidine
A
C
G
T
G A
CT
• ii) Transversion: Purine Pyrimidine Pyrimidine Purine
→ or →
→ or →
Pyrimidine Purine Purine Pyrimidine
A
T
T
C
G
G
C
A
3. Insertion
• Insertions are mutations in which extra base pairs are inserted into a new place in the DNA.
4. Deletion
• Deletions are mutations in which a section of DNA is lost, or deleted.
• If it occurs in coding sequences and involves one, two or more nucleotides which are not a multiple of three, it will disrupt the reading frame.
5. Frameshift Mutation• Mutation caused by the addition or deletion of a
base pair or base pairs in the DNA of a gene resulting in the translation of the genetic code in an unnatural reading frame from the position of the mutation to the end of the gene