Yanofsky
precisely mapped the positions of a series of
mutations in the TrpA gene
trpA-1
trpA-2
trpA-1
trpA-3
trpA-2
trpA-1
trpA-3
trpA-1
Low recombination
frequencies show that
theses mutations are closely linked
High recombination frequencies show
that these are far apart