Lecture 2: Recessive mutations File Flashcards
(41 cards)
What are genetic differences created by ?
Sex (recombination)
Spontaneous mutation
How many new mutations are in a child (compared to parent) ?
100-200
Name the three main origins of spontaneous mutations
- Replication/repair errors
- DNA damaging agents
- Ionising radiaion
DNA damage - repair = ?
DNA damage - repair = Net mutation
How would you increase mutation rate ?
increase amount of DNA damage,
or decrease rate of repair
How do you induce mutation ?
Use chemical mutagens or radiation
how many times more mutations can be made using mutagens
> 1000 fold
Name 2 things that ALL mutagens do
- Damage DNA (cause mutation)
2. cause cancer
Name two unimportant regions
- Between genes
2. Between exons
Most mutations are silent unless ____?
unless they affect the protein coding part of genes (or their expression)
what is a silent mutation?
One base changes, but end protein is the same
Whats is a nonsense mutation?
One base changes and stops protein production (forms a stop codon)
What are the two types of missense mutation?
Conservative and non-conservative
what is conservative missense mutation?
The mutation causes a different final protein, but the protein is in the same group as the original (e.g. acidic)
What is non-conservative missense mutation?
The mutation causes a different final protein, but the protein is in a different group from the original (e.g. alkaline)
Name the two types of frameshift mutations
- Insertion
2. Deletion
Name base modifier chemical mutagen
EMS (point mutations)
Name base analogue chemical mutagen
5BU (point mutations)
Name intercalating agent chemical mutagen
Acridine dyes (Frame-shift)
Thymine dimers are caused by what ?
UV light
Thymine dimers lead to …..
Frame-shift mutations
Give an example of ionising radiation and name the resulting mutations
X-rays, result in chromosomal breaks (deletion, translocation and inversion)
What is aneuploidy?
The presence of an abnormal number of chromosomes in a cell
What causes downs syndrome and what are main phenotypes?
Extra chromosome 21
short stature, mental retardation and susceptible to alzheimers disease
