Theme 2D Mutations Flashcards
What are mutations
Changes to nucleic acid sequence (DNA and RNA)
Primary force in evolution where natural selection favours beneficial mutations
More likely to be harmful than beneficial
What happens if the gene sequence is altered?
It can change the amino acid sequence of the polypeptide which result in variation of phenotype
If the gene sequence is altered, what can be the effect on the phenotype?
It can be harmlesss/neutral, harmful/deleterious, or beneficial/advantageous
What are germline mutations?
Mutations that originally occurred in gametes and are therefore heritable
Give an example of a germline mutation
A gender influence trait, so a dominant trait that is dependent on gender
example a man’s ring finger is bigger than his index finger
What are somatic mutations? What cells do they occur in
These mutations happen in all other cell types, other than gametes meaning, they are not heritable
Occurs in progenitor cells (cells that turn into other cells), and all other daughter cells will express the mutation
What are somatic mutations expressed as?
Sectors, so the size of mutation depends on the time of mutation
If the mutation occurs earlier, there’s more sectors of mutation and vise versa
Example of a somatic mutation
Cancer tumours
What are small scale mutations?
What are the types of small scale mutations?
Changes to one or a few base pairs
Base substitution
Insertion
Deletion
transitions
Tranvsersions
What is a base substitution mutation
A single nucleotide change as a result of a point mutation
Example C changes to T
What is an insertion mutation?
One or more base pairs, added to the sequence during DNA replication, which results in a frameshift mutation
What is a deletion mutation?
One or more base pairs, skipped during DNA replication, which result in a frameshift mutation
What is a transition mutation?
Purine to purine (a to g)
or pyrimidine to pyrimidine changes (c to t)
What is a transversion mutation?
Purine to pyrimidine (G to C)
Or pyrimidine to purine changes (C to A)
What is the effect of point mutations on the amino acid sequence of polypeptides?
You can get missense mutations, nonsense, mutation, silent mutations, or frameshift mutations