High Resolution Mapping by Analysis of Recombination Frequency Flashcards
How can conjugation be used for high-resolution mapping of genes on the E.coli chromosome via analysis of recombination?
In order for the DNA sequence to be conserved an even number of recombination events must take place (i.e reforming the circular chromosome). Can look at the frequency of recombination, i.e how much certain combinations occur to determine the distance between markers on a specific sequence. The information we ascertained from by time of entry mapping aids in this.
Describe the process of transduction.
Transduction was first discovered Lederberg and Zinder. Who was still getting recombination even though no cell-to-cell contact was occurring, a tiny component is able to pass through the sieve and pass on genetic information (a bacteriophage). A phage, when packaging itself in a cell, may accidentally grab some of the bacterial genome, rather than the viral. Upon infection of another cell, rather than injecting its own genome, it inadvertently injects the bacterial genome.
How can transduction be used to map closely linked genes?
Two crossovers are required to incorporate the transduced DNA into the recipient genome. The further apart two co-transduced markers are, the more likely they are to be separated by recombination.
