Lecture 18 Outline of Last Lecture 1. Turbidostat2. Environment & Growth3. -PhilesOutline of Current Lecture 1. Genome2. Mutation3. Gene Transfer Systems & RecombinationCurrent LectureChapter 12- Genomics & GeneticsGenome- Important information of functioning- Wild type (wt)- Mutant. Benchmark- Genotype- Genetic makeup. Specific sequence of nucleotides- Phenotype- Physical characteristics that you can seeMutations - Tight- cannot be grown in absence of whatever they need. Display mutant phenotype clearly. - Leaky- Displays phenotype slightly different from wild type. Stable or Unstable- Frequency at which mutation will revert back to wild type on its own…- Stable- good physiological condition. Doesn’t revert back (or very infrequently)- Unstable- - Reversion- Returning to wild typeConditional Mutations- Express mutant phenotype under certain conditions- When you see wt- under permissive conditions- Express mutant wt- non permissive conditionsHis+ or His-Prototroph-Auxotroph- BSC 160 1nd EditionHow do we approach Selection?- Selecting Media- Screens- looking colony by colony, hope to grow what you want to grow. Time consumingWhy Make Mutants?Gene Transfer Systems & Recombination- Genetic recombination- occurs when an organism acquires & expresses genes that originated in another organism3 means for genetic recombination in bacteria:1. Conjugation2. Transformation3. TransductionConjugation-Transfer of plasmid or chromosomal fragment from donor cell to a recipient cell via direct connectionTransformation- Chromosome fragments from a lysed cell are accepted by a recipient cell; the genetic code of the DNA fragment is acquired by the recipientTransduction- Bacteriophage serves as a carrier of DNA from a donor cell to a recipient
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