Mutation Flashcards
Why do we care about mutation?
Because mutation is the source of ALL variation in populations
Why do we care about variation?
Because evolution operates by shifting patterns of variation in populations, over generations
Mutation
A random change in the genetic code resulting from errors in DNA replication
Before cell division…
Double DNA in the nucleus
How common is mutation?
Some estimates of an average mutation rate in human populations (at a given locus):
~ 0.1 per million genes per generation
~ 10 per million genes per generation
In a population of one million, how many people will have a mutation at a specific locus?
0-10 people
Phenotypic effects of a mutation will only appear if the mutation occurs where?
The coding region
3 categories of mutation?
1.) Point mutations
2.) Insertions/deletions
3.) Chromosomal rearrangment (ex. inversion)
Point mutation
A single base change in a gene
Hemoglobin
a protein that transports oxygen in our blood
- a single base substitution leads to a single amino acid substitution in the hemoglobin beta chain is the cause of sickle cell disease
Single base change in DNA triplet results in a different amino acid for Hemoglobin
CTC translates for Glutamic Acid
CAC translates for Valine*
Missense variant/non-synonymous change
a mutation that changes the amino acid
Not every point mutation will change the amino acid and this is due to what?
Redundancy in the triplet–> amino code
- SYNONYMOUS CHANGE
Polymorphism/Polymorphic
The existence of multiple forms
- a variant occurring at over 1% frequency in a population or sample
Single base change
Known a a Single Nucleotide Variant (SNV)
