Chapter 7.3: What Mutations Tell Us About Gene Structures Flashcards
Describe mutation and deletion relationhip
No wild-type progeny can arise in a cross between a mutation on one chromosome and a deletion on the corresponding region on another chromosome If the mutation lies outside the region deleted from the homologous chromosome, wild-type progeny can appear)
Define cis confuration
Two mutations on the same chromosome
Define cistron
Benzer called any complementation group identified by the cis-trans test
Define trans configuration
Two mutations on different chromosomes
Describe Benzer’s complementation testing
Describe how Benzer plated T4 baceriophages
What is the recombination frequency formula?
RF = (number of plaques on E.coli K(λ)/number of plaques on E.coli B) x2
Describe how the t4 strains appeared on the plates for each E.coli strain in Benzer’s experiment
What is a mutant complement group?
o A collection of mutations that do not complement each other is known as a complementation group
Describe Benzer’s recombination testing
What is Two mutations on the same chromosome?
cis configuration
What are mutation hotspots?
Some sites within a gene spontaneously mutate more frequently than others and as a result are known as mutation hotspots
Benzer called any complementation group identified by the cis-trans test a?
cistron
What is Two mutations on different chromosomes ?
trans configuration
Describe mutant complementation testing
o If two homologous chromosomes in an individual each carry a mutation recessive to wild type, a normal phenotype will result if the mutations are in different genes The dominant wild-type alleles on each of the two homologs can make up for, or complement, the defect in the other chromosome o If the recessive mutations on the two homologous chromosome are in the same gene, no wild-type of that gene exists in the individual No complementation will occur
