Lecture 3 Flashcards
What was known about genetics in the 50’s
Genes are arranged on chromosomes
DNA is the genetic material
What is a bacteriophage?
Virus that infects bacteria
What are the features of a bacteriophage?
- Easily and rapidly grown
- Genetically very simple
What strains of E.Coli could Wild Type T4 infect?
Strains K and B
What E.Coli strain did rII mutant phage form large plaques on?
E.Coli strain B
What E.Coli strain could rII mutant phage not form large plaques on?
E.Coli strain K
What is complementation?
Production of wild type phenotype when two haploid genomes are present in the same cell
Each mutant can provide the others’ missing function
What is recombination?
A process that generates new gene combinations
In Benzer’s recombination experiment, what did the plaques indicate?
That the wild-type phage was formed by recombination. This occurred between two rII mutant chromosomes inside E.Coli Strain B cells
(prior to this, mutants infected Strain B and recombination occurred. Progeny phage were moved to Strain K (rII can’t grow but the wild-type could. So by having plaques it meant recombination had occurred.)
What does the number of plaques indicate?
Frequency of recombination events, this corresponds to the distance between mutations in the DNA
What was Benzer’s Map derived from?
Frequency of recombination between different mutations
What do hotspots on Benzer’s Map indicate?
Multiple mutations
Finish the sentence
Genetic maps are …
Linear
