Chapter 7.1: Mutations: Primary Tools of Genetic Analysis Flashcards
What occurs when a base at a certain position in one strand of the DNA molecules is replaced by one of the other three bases?
substitution
What is a point mutation?
o Point mutations (transitions, transversions, and small deletions or insertions) that affect one or just a few base pairs in the DNA and thus alter only one gene at a time
What is a substitution mutation?
o A substitution occurs when a base at a certain position in one strand of the DNA molecules is replaced by one of the other three bases; after DNA replication, a new base pair will appear in the daughter double helix
What is a reverse mutation, or reversion?
o Mutations can also cause a novel mutant allele to revert back to wild type (a to A+, or B to b+) in a process known as reverse mutation, or reversion
What occurs when a block of one or more nucleotide pairs is last from a DNA molecule?
deletion
What is is the addition of one or more nucleotide pairs?
insertion
What is an insertion mutation?
o An insertion is the addition of one or more nucleotide pairs
What is a transition mutation?
purine for purine or pyrimidine for pyrimidine
What is a transversion mutation?
purine for pyrimidine or vice versa
What affect one or just a few base pairs in the DNA and thus alter only one gene at a time?
point mutations
What is a deletion mutation?
o A deletion occurs when a block of one or more nucleotide pairs is last from a DNA molecule
What is o A mutation that changes a wild-type allele of a gene to a different allele ?
forward mutation
What are o Mutations can also cause a novel mutant allele to revert back to wild type?
reverse mutations, or reversion
What is a forward mutation?
o A mutation that changes a wild-type allele of a gene to a different allele is called a forward mutation
Recessive: A+ to a; dominant: b+ to B
