10 Questions
Which type of mutation involves the replacement of one nucleotide with another?
Missense mutation
What is the term for a sequence change where one or more nucleotides are lost compared to a reference sequence?
Deletion mutation
Which type of mutation introduces a premature stop codon?
Nonsense mutation
What is the term for mutations that affect coding sequences or splice sites?
Point mutations
Which type of mutation results in the modification of a codon without changing the coded amino acid?
Synonymous mutation
What is the definition of a duplication mutation?
A sequence change where a copy of one or more nucleotides is inserted directly 3' of the original copy of that sequence.
Which type of mutation involves the insertion of one or more nucleotides that are not a copy of a sequence immediately 5'?
Insertion mutation
What is the characteristic of an in-frame mutation?
It does not alter the reading frame
What is the effect of a null or amorphic mutation on gene activity?
No product - mRNA or protein; no function
In a recessive mutation, when are the mutant phenotype observed?
In an individual carrying two mutant alleles
Study Notes
Types of Mutations
- Point mutation: involves the replacement of one nucleotide with another.
- Deletion: a sequence change where one or more nucleotides are lost compared to a reference sequence.
- Nonsense mutation: introduces a premature stop codon.
- Missense mutation: affects coding sequences or splice sites.
Mutation Effects
- Silent mutation: results in the modification of a codon without changing the coded amino acid.
- Duplication mutation: a type of mutation that results in the duplication of a sequence.
- Insertion mutation: involves the insertion of one or more nucleotides that are not a copy of a sequence immediately 5'.
- In-frame mutation: a type of mutation that maintains the original reading frame of the sequence.
Mutation Consequences
- Null or amorphic mutation: completely eliminates gene activity.
- Recessive mutation: the mutant phenotype is observed only when an individual is homozygous for the mutation (has two copies of the mutated gene).
Test your knowledge of gene variants, mutations, and their structural classifications with this quiz. Explore the different types of DNA sequence alterations, including deletions, duplications, and chromosomal rearrangements.
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