With these markers established, researchers will then be able to determine the most effective combination of resistance genes.

If there are no resistance genes, the population may disappear.

This variation in resistance genes means no one parasite strain is able to sweep through the whole population.

In both cases this interaction may evolve to a full resistance gene given the appropriate selection pressure.

Worms that are resistant survive and pass on their "resistance" genes.

The idea is to let the resistance genes drown in a huge gene pool of nonresistance.

And, more important, how common are resistance genes in target insect populations?

One is a plant gene called the resistance (R) gene.

There are a number of ways to get a resistance gene:

Why do resistance genes persist and spread throughout bacterial populations?