Types Of Mutations
- Alternations to the usual DNA
seq of an org that results from the action of chemical and physical agents
or errors in DNA replication
- They are perpetuated by cell
- Org may have wild type/mutant
- Only mutations in coding
region affect protein synthesis.
- There are various ways to
- SPONTANEOUS V/S INDUCED MUTATION
- SOMATIC V/S GERMINAL MUTATION
- POINT/GENE MUTATIONS V/S CHROMOSOMAL MUTATIONS
Involve a change in the base present at any position in a gene.
DNA RNA PROTIEN
ACA - UGU - CysteiN
ACC - UGG - Tryptophan
DNA RNA PROTIEN
ACA - UGU - Cystein
ACT - UGA - stop codon
CTC CTC CTC CTCC CTC CTC
GAG GAG GAG GAGG GAG GAG
Eg CAA, CCG, CCT, CCC - glycine
alteration of longer DNA stretches
Involves a single break and capping of the broken end with a telomere.
A ring chromosome is formed from 2 terminal deletions. There is a break in both the long and short arm, with the fusion of ends of centromeric segment and loss of the 2 terminal seg.
Involves 2 breaks with loss of interstitial seg.
The duplicated seg remains adj to the normal corresponding section of the chromosome.
Duplicated seq is in the reverse order of the normal seq.
The duplicated seg is loacated in the same chromosome but away from normal seg
The duplicated seg is located on a homolougous chromosome.
Segments of 2 different non homologous chromosomes have been exchanged
2. Robertsonian translocation
Involvesbrea in each arm of the chromosome , 180 degree rotation of the centric seg. And reuninon of the terminal seg. With centric seg.
AB|C.DE|FGHI = ABED.CFGHI
Involves 2 breakes in the same arm ,180 degree rotation f the interstitial seg and reunion of the terminal seg with interstitial seg.
- MUTATIONS AFFECTING MORPHOLOGICAL TRAITS
- These mutations can be visualized phenotypically and are imp for experimental genetics
- Eg. Various mutants of drosophila (eye color)
- MUTAIONS EXHIBITING NUTRITIONAL VARIATIONS IN PHENOTYPE
- These have been studied in bacteria and fungi in which mutants failed to synthesize an amino acid or a vitamin
- MUTATIONS EXHIBITING BIOCHEMICAL VARIATIONS IN PHENOTYPE.
- These mutations affect essential metabolic pathway resulting into disorders.
- Eg. Sickle cell anemia, hemophilia
- BEHAVIORAL MUTATIONS
- These mutations affect the behavioral patterns of an org such as mating behavior
- Eg. Mating behavior of a fruit fly maybe impaired if it cannot beat its wings
- LETHAL MUTATIONS
- These mutations interrupt the processes that are essential to the survival of the org.
- Eg a mutant bacterium that cannot synthesize a specific amino acid it needs will be unable to grow and divide if plated in a medium lacking that amino acid.
- Other eg. Tay-Sachs diseases and Huntington's diseases in Human.