Closely related resistance genes can act against totally different pathogens and pests.
For example, the nematode resistance gene Gpa2 is virtual identical to the Rx1 resistance gene against the potato virus X. R-genes are build of several functional domains: regions involved in pathogen recognition and regions involved in mediating the resistance response.
The questions we like to answer are 1) which part of the R-gene is responsible for the recognition of nematodes ? 2) which part is involved in the resistance mechanism? Are domain swaps and deletion constructs still functional? What happens to the R-gene product in the cell after recognition of the nematode? To answer these questions you will make use of a wide range of molecular biological techniques and advanced spectral microscopy.