Unit 7 - Gene Mutation Flashcards
What is a mutation?
A change in a gene’s nucleotide base sequence that affects less than 1 percent of a population and can cause a mutant phenotype.
A polymorphism is more common and may not alter the phenotype.
What is a germline mutation?
A mutation that originates in meiosis and affects all cells of an individual.
What is a somatic mutation?
A mutation that originates in mitosis and affects a subset of cells.
What are loss-of-function mutations typically associated with?
Usually recessive.
What are altered or gain-of-function mutations typically associated with?
Dominant.
What disorders can mutations in the beta globin and collagen genes cause?
Sickle cell anemia & Thalassemia (B-globin) and Osteoarthritis (Collagen)
Do different mutations in a gene always cause the same illness?
No, it varies; nomenclature is inconsistent.
What is a spontaneous mutation?
A mutation that arises due to chemical phenomena or an error in DNA replication.
What is a spontaneous mutation rate?
It is characteristic of a gene and is more likely in repeats.
What are mutagens?
Chemicals or radiation that delete, substitute, or add bases.
How can an organism be exposed to a mutagen?
Intentionally, accidentally, or naturally.
What is a point mutation?
A mutation that alters a single DNA base.
What are the two types of point mutations?
Transition and transversion.
What is a missense mutation?
A mutation that substitutes one amino acid for another.
What is a nonsense mutation?
A mutation that substitutes a ‘stop’ codon for a codon that specifies an amino acid, shortening the protein product.
