Gene Mutation Flashcards
Germ-line mutations
mutations passed through the gametes
Somatic Cell Mutations
Show patches of affected areas, no gametes will carry the mutations.
Spontaneous Mutations
Occur naturally. A baby will have an average of 60 new mutations, 90% will be in non-coding regions
What percentage of DNA actually codes for proteins?
1.5%
What are induced mutations caused by?
Mutagens
Chromosomal mutation effects can result in:
Duplications
Inversions
Deletions
Insertions
Translocation
Mutations in nucleotide sequences include:
point mutations
base substitutions
insertions
deletions
A point mutation is:
A substitution of a single base nucleotide with another nucleotide (doesn’t effect the number of nucleotides)
Silent Mutation
Does not change the amino acid encoded by the codon and includes mutations occuring in introns.
Missense mutations
Changes the amino acid encoded by the codon.
Why would a missense mutation be harmless?
If the amino acid that the changed codon produces is chemically similar to the one the non-mutated gene codes for, or if it is in an unimportant area.
Why would a missense mutation be harmful?
A chemically different amino acid can cause changes in structure and function, such as in sickle cell anaemia in which the change from Glu to Valine results in a structural change in the RBS that effects its function.
Nonsense Mutation
Changes an amino acid codon to a termination (stop codon). the resulting amino acid is shortened.
Sense Mutations
Converts a stop codon to a sense codon.
What causes a Frameshift Mutation?
Insertions or deletions of a single base pair.