Douglas W Drury | Search bioRxiv

bioRxiv2016

Evolutionary Genetics of Insecticide Resistance and the Effects of Chemical Rotation

Repeated use of the same class of pesticides to control a target pest is a form of artificial selection that leads to pesticide resistance. We studied insecticide resistance and cross-resistance to five commercial insecticides in each of six populations of the red flour beetle, Tribolium castaneum. We estimated the dosage response curves for lethality in each parent population for each insecticide and found an 800-fold difference among populations in resistance to insecticides. As expected, a naive laboratory population was among the most sensitive of populations to most insecticides. We then used inbred lines derived from five of these populations to estimate the heritability (h2) of resistance for each pesticide and the genetic correlation (rG) of resistance among pesticides in each population. These quantitative genetic parameters allow insight into the adaptive potential of populations to further evolve insecticide resistance. Lastly, we use our estimates of the genetic variance and covariance of resistance and stochastic simulations to evaluate the efficacy of \"windowing\" as an insecticide resistance management strategy, where the application of several insecticides is rotated on a periodic basis.

Evolutionary Biology↗

bioRxiv2016

CRISPR/Cas9 gene drives in genetically variable and non-randomly mating wild populations

Synthetic gene drives based on CRISPR/Cas9 have the potential to control, alter or suppress populations of crop pests and disease vectors, but it is unclear how they will function in wild populations. Using genetic data from four populations of the flour beetle Tribolium castaneum, we show that most populations harbor genetic variants in Cas9 target sites, some of which would render them immune to drive (ITD). We show that even a rare ITD allele can reduce or eliminate the efficacy of CRISPR/Cas9-based synthetic gene. This effect is equivalent to and accentuated by mild inbreeding, which is a characteristic of many diseasevectoring arthropods. We conclude that designing such a drive will require characterization of genetic variability and the mating system within and among targeted populations.

Genetics↗