Download Ch 17 DNA mutations

DNA Mutations and Repair
Chapter 17
Part 1
Gene Mutations and Repair

Nature of mutations

Causes of mutations

Study of mutations

DNA repair
Nature of Mutations
Chernobyl, April 26th, 1986
Mutation: is defined as an inherited
change in genetic information by cell
division or individual organisms.
Mutations can be classified into categories.
Categories of mutations
Somatic and germ line
Achondroplasia
Autosomal Dominant
Gene Mutations can also be classified by type of mutation

1. Base Substitutions
□ 2. Insertions and deletions
Lead to

3. Frameshift mutations

4. Expanding trinuleotide repeats
Gene Mutations can also be classified by type of mutation

Base Substitutions
can be
Transitions and Transversions
PURINE TO PURINE
PURINE TO PYRIMIDINE
PYRIMIDINE TO PURINE
Expanding trinucleotide repeats
Fragile X Syndrome
Pre-mutation
Fragile X syndrome:FMR-1 gene
Strand slippage may cause repeats
Spontaneous: slippage
Phenotypic changes and mutations
Forward mutation
Reverse mutation
Forward versus Reverse Mutations
Terms associated with PHENOTYPIC effects of mutations on protein structure
Can be “neutral”
redundancy
Phenotypic effects can also change function
Gain of Gene Function
1
1
Sullivan, J.P. et al.,
Department of Pathology,
College of Veterinary Medicine, 1998
The University of Georgia, Athens, GA
or
Loss of Gene Function
Qualtek Molecularlabs Web Site
2
Loss of Function can also occur!
Typically recessive mutations!
Suppressor Mutations is a genetic change that hides the
effect of another mutation
Intragenic Suppressor Mutations
Intergenic Mutation
Lethal Mutations
Do you remember something about each type of mutation?