Module 3: Genetic Variation Flashcards
What do mutagens do?
- Either alter the chemical structure of DNA
- Or cause breaks in the DNA strands
What types of mutagens are there?
- Environmental
- Biological
- Somatic - aren’t passed to children
- Germline - are passed to children
Haploinsufficiency
When a mutagen prevents the production of the full amount of proteins
Micro Mutation
Changes at the DNA strand level
Macro Mutation
Changes at the chromosome level
Substitutions
- Micro gene mutation
- One base is replaced by one of the other three bases
Deletion
- Micro gene mutation
- One or more base pairs is lost
Insertion
- Mirco gene mutation
- One or more base pairs is added
Missense Mutation
- Changes one amino acid to another one
- May or may not affect protein function based on the role of the amino acid
Nonsense Mutation
- Changes the amino acid to a STOP codon
- Causes premature termination of translation
Silent Mutation
- Doesn’t change an amino acid
- Can affect the phenotypic effect by changing the rate of protein synthesis or gene splicing
Frameshift Mutation
- Frame = codon
- A shift during translation that can cause deletion or insertion
- This can cause many amino acid changes or a premature STOP codon
Genomic Mutations
- Macro changes
- Duplication
- Inversion
- Deletion
- Insertion
- Translocation
Genetic Polymorphisms
- Natural variations in a gene, DNA sequence, or chromosome
- They have no adverse effects on the individual
- Very common
Types of Genetic Polymorphisms
- Single Nucleotide polymorphisms (SNP’s)
- Microsatellites
- Copy number variation
Single Nucleotide Polymorphism
- SNP’s (sounds like snips)
- A single nucleotide variation in a genetic sequence
- Most common type of polymorphism
- These act as landmarks when studying correlations w/ disease, drug response, & other phenotypes in the human genomes
- Example: rheumatoid arthritis, sickle cell anemia
Microsatellites
- Simple sequence repeats & short tandem repeats
- Helps map the genome, paternity testing, & ancestry testing
Copy Number Variation
- CNV
- The number of copies of a specific gene varies from one person to the next
- Looks more at the chemical differences than the phenotype differences
What are the applications of polymorphism application?
- Ancestry testing
- Pharmacogenetics
- Forensics
- Paternity testing
- Genome mapping
A skin cancer caused by sun exposure is an example of ___
Environmental somatic mutations
(True/False) All genetic mutations result in a clinically identifiable condition
False
Sickle cell anemia is an example of _____
- DNA substitution
- Single Nucleotide Polymorphism (SNP’s)
Which of the following point mutations is least likely to cause a change in protein structure?
Silent
(True/False) Genetic polymorphisms are very rare causes for human disease
False
