6 - Mutations Flashcards
What is the frequency of gene mutations?
Spontaneously and random
What is a point mutation?
A change in one of the base pairs in a DNA sequence of a single gene
What are the three types of point mutation?
Substitution
Insertion
Deletion
What do the different types of point mutation result in?
One or more codons for one or more amino acids being altered
What kind of change does substitution being about?
Usually just a small change, since it only alters one amino acid
What kind of change do insertion and deletion bring about?
A larger change, since it will alter all the amino acids from the mutation point
What is a splice-site mutation?
When a point mutation occurs on a site where introns are normally removed from the primary mRNA transcript
What could splice-site mutations lead to?
Introns being left in the mRNA transcript, which could be translated into a protein that doesn’t function properly
Why are mutations important for evolution?
They are the only source of new variation
Describe the nature of most mutations
Most mutations are harmful but occasionally a mutation will arise that confers an advantage on the organism, which are selected by natural selection, acting as the raw material for evolution
What is a chromosome mutation?
A mutation that involves the breakage of one or more chromosomes
What are the four types of chromosome mutation?
Deletion
Duplication
Inversion
Translocation
What is polyploidy?
When an error occurs during gamete formation or cell division, leading to cells receiving one or more extra chromosome sets
What is a triploid cell?
A cell with three copies of the genome
What is a tetra-plaid cell?
A cell with four copies of the genome
