Types of Mutation :- Frameshift, Reversion and Spontaneous

Mutation is the random process whereby genes change from one allelic form to another.
Mutation can occur in two directions; mutation from wild type to mutant is called a forward mutation, and mutation from mutant to wild type is called a back mutation or reversion.

1. Types Of Mutation Frameshift, Reversion and Spontaneous

2. Introduction http:// alsn.mda.org/files/alsn/imagecache/story_main_image_620x/DNA-letters-with-mutation_0.jpg

3. N ucleic acids are the building blocks of  DNA and RNA. T hey carry the long-term memory of the information required for an organism's reproduction . Given the complexity of DNA and the vast number of cell divisions that take place within the lifetime of a multicellular organism, copying errors are likely to occur . Mutation is the random process whereby genes change from one allelic form to another . Mutation can occur in two directions; mutation from wild type to mutant is called a forward mutation, and mutation from mutant to wild type is called a back mutation or reversion . In this presentation we are going to see in detail about three of such mutation that occur i.e. Frame-shift, Reversion and Spontaneous.

4. Frameshift Mutation https:// s3.amazonaws.com/test.classconnection/462/flashcards/12462/jpg/picture8.jpg

5. A frameshift mutation is a genetic mutation caused by a deletion or insertion in a DNA sequence that shifts the way the sequence is read. T he normal sequence of codons is disrupted by the insertion or deletion of one or more nucleotides, provided that the number of nucleotides added or removed is not a multiple of three . Frameshift mutations result in abnormal protein products with an incorrect amino acid sequence that can be either longer or shorter than the normal protein. http:// study.com/cimages/multimages/16/insertion_mutations1.png

6. Reversion Mutation http:// biosiva.50webs.org/dam.ht8.gif

7. Reverse mutation (reversion) is the production by further mutation of a permutated gene from a mutant gene . R eversion is the correction of a mutation, i.e. it occurs at the same site; more loosely, though, the term is applied also to a mutation at another site that masks or suppresses the effect of the first mutation. In fact, such organisms are not non-mutant, but are double mutants with the same phenotype . Two types:- True reversion is the reversal of the original nucleotide change. P henotypic reversion can result from changes that restore a different amino acid with properties identical to the original. Second-site changes within a protein can also restore normal function. https://classconnection.s3.amazonaws.com/735/flashcards/1780735/jpg/direct_reversion_( revertant_type_of_mutation)1349317582770.jpg

8. Spontaneous Mutation https:// upsbiol302.files.wordpress.com/2008/11/spon_vs_mut.jpg

9. Spontaneous mutations arise from a variety of sources, including errors in  DNA   replication , spontaneous lesions, and transposable genetic elements. These are mutations that are a result of natural changes in DNA structure . All types of point mutations can occur spontaneously, during S, G1 and G2 phases of the cell cycle, or by the movement of transposons . The spontaneous mutation rate in eukaryotes is between 10-4-to-10-6 per gene per generation, and in bacteria and phages 10-5-to-10-7/gene/generation. Genetic constitution of the organism affects its mutation rate. Spontaneous mutations Caused mainly by Spontaneous replication errors:- 1. Tautomeric shifts 2. Wobble base pairing 3.Strand slippage 4.Unequal crossing over 5.Spontaneous Chemical Changes i . Depurination ii. Deamination

10. Reference

11. http:// www.slideshare.net/sreerajsree/spontaneous-and-induced-mutations http:// ghr.nlm.nih.gov/handbook/mutationsanddisorders/possiblemutations https:// youtu.be/eDbK0cxKKsk http:// study.com/academy/lesson/mutagens-and-the-effects-of-frameshift-mutations-definitions-and-examples.html http ://www.ncbi.nlm.nih.gov/books/NBK21897/ https://www.ndsu.edu/pubweb/~mcclean/plsc431/mutation/mutation3.htm http://www.nature.com/scitable/topicpage/genetic-mutation-1127 http://medical-dictionary.thefreedictionary.com/reverse+mutation

12. THANK YOU Dvane Coutinho [email protected]