Another bacterial mapping exercise.

Here's another question you could practice with.  Sketch a single chromosomal map with the loci spaced out properly.  Include the site of Hfr insertion for each of the four strains, indicating proper polarity (direction in which it inserted).

The answer is here.

Replica Plating / Interrupted Mating Gene Mapping

In bacteria, gene mapping is accomplished differently from eukaryotes.  For one thing, they're haploid, and so we're not going to see nonparentals!

Replica plating is done to look for the genotypes of exconjugants, and this presentation doesn't talk about conjugation, F^-, F⁺, or Hfr strains.  You have to know those things before this exercise.  Your textbook probably doesn't go into replica plating too much, so the "Solution" to the problem below gives a bit of information on that.

Here's the exercise.  Try it before looking at the solution!

And now - the solution!