Genetic Tools

Genes Deleted by Recombination
Genes Identified by  REMI

 

Use of phenotype to select point mutations and genomic insertions.
Photo at left shows multiple wild-type plaques (~ 1 cm) and single aggregation deficient plaque.  Photo at right shows multiple mutant plaques and single revertant plaque.  Among the available genetic techniques are homologous recombination used to create null mutants in known genes for use epistasis, random mutagenesis, and GFP-tagging studies.  Restriction enzyme mediated integration (REMI) is used to identify new genes and for suppressor analysis:

LOSS-OF-FUNCTION	GAIN-OF-FUNCTION
Homologous Recombination	Restriction Enzyme Mediated Insertion
Epistasis	Novel Genes
Random Mutagenesis	Suppressors
GFP-tagging

 

 

Illustration of REMI technique to generate genomic insertions and rescue mutated genes.
Random insertion of plasmid containing drug resistance marker may disrupt a gene.  The DNA flanking the insertion is rescued by transformation of E coli with genomic DNA.  The gene is then knocked out in the original wild-type strain to verify that it is required for the lost function: