Mutations

Question 1

Name 6 types of mutations

Answer 1

• substitutions
• deletions
• insertions
• inversions
• transpositions
• chromosomal

Question 2

What are substitutions?

Answer 2

When one base is replaced with another

Question 3

Name 4 different types of substitution mutations

Answer 3

1. Synonymous - produce same amino acid
2. Non-synonymous - produce different amino acid
3. Nonsense - stop codon produced causing truncation
4. Readthrough - causes extension

Question 4

What does 1/2 nucleotide loss/addtion result in?

Answer 4

Frameshift mutation where coding region from that point forward is changed

Question 5

Name 3 different types of insertions/deletions and their consequences

Answer 5

1. Deletion of regulatory sequence - causes uncontrolled transcription
2. Deletion of core promoter - results in no transcription
3. Duplications - can cause expression to double/triple, copy can accumulate mutations causing a pseudogene (pseudogenisation) or can remain functional and adopt a different action (neofunctionalisation)

Question 6

What are inversions?

Answer 6

180 degree rotation of a segment of a gene, function can be maintained if breakpoint is outside of the gene

Question 7

What is transposition?

Answer 7

When a segment of DNA moves to a new position either on a closeby or to a non-homologous chromosome. This can be reciprocal or non-reciprocal.
Transposable elements can insert themselves on to different positions on a gene