Gene Mutations Flashcards
How do mutations drive evolution?
They give rise to genetic diversity.
What are polymorphisms?
Multiple Wt alleles for one gene.
What is a forward mutation?
Change from Wt to mutant.
What is a reverse mutation or reversion?
Change from mutant to Wt
Are mutations random or adaptive?
Random
In the experiment conducted by Luria and Delbruck, what results would suggest that mutations are adaptive?
In generations exposed to the toxin, the number of colonies resistant is constant between cultures.
In the experiment conducted by Luria and Delbruck, what results would suggest that mutations are random?
In generations exposed to the toxin, the number of colonies resistant varies greatly between cultures.
What are prototrophs?
Wt bacterial strains that can grow on minimal media
What are auxotrophs?
Mutants that cannot synthesise own amino acids.
What is the effect of mutations in promotor or regulatory elements?
Increase or decrease in transcription.
What is the effect of mutations in the 5’ or 3’ end?
Altered ability of mRNA translation and/or stability
What is the effect of mutations in the splice site?
pre-mRNA may not be spliced correctly, resulting in a frame-shift mutation.
Which mutations can be passed on to offspring- somatic or germ line?
Germ line.
What are conditional mutations?
Mutations that affect a phenotype only under specific condition. E.g. fly mutants- temperature.
In which two cases are loss-of-function alleles dominant?
Haploinsufficiency and dominant-negative.
