A Linkage Map and QTL Analysis for Pyrethroid Resistance in the Bed BugCimex lectularius

Abstract

The rapid evolution of insecticide resistance remains one of the biggest challenges in the control of medically and economically important pests. Insects have evolved a diverse range of mechanisms to reduce the efficacy of the commonly used classes of insecticides, and finding the genetic basis of resistance is a major aid to management. In a previously unstudied population, we performed an F2 resistance mapping cross for the common bed bug, Cimex lectularius, for which insecticide resistance is increasingly widespread. Using 334 SNP markers obtained through RAD-sequencing, we constructed the first linkage map for the species, consisting of 14 putative linkage groups (LG), with a length of 407 cM and an average marker spacing of 1.3 cM. The linkage map was used to reassemble the recently published reference genome, facilitating refinement and validation of the current genome assembly. We detected a major QTL on LG12 associated with insecticide resistance, occurring in close proximity (1.2 Mb) to a carboxylesterase encoding candidate gene for pyrethroid resistance. This provides another example of this candidate gene playing a major role in determining survival in a bed bug population following pesticide resistance evolution. The recent availability of the bed bug genome, complete with a full list of potential candidate genes related to insecticide resistance, in addition to the linkage map generated here, provides an excellent resource for future research on the development and spread of insecticide resistance in this resurging pest species.

A High-Density Linkage Map Reveals Sexual Dimorphism in Recombination Landscapes in Red Deer (Cervus elaphus)

“…Linkage maps are often an early step in this process, using information on recombination fractions between markers to group and order them on their respective chromosomes ( Sturtevant 1913 ; Lander and Schork 1994 ). Ordered markers have numerous applications, including: trait mapping through quantitative trait locus mapping, genome-wide association studies, and regional heritability analysis ( Bérénos et al 2015 ; Fountain et al 2016 ); genome scans for signatures of selection and population divergence ( Bradbury et al 2013 ; McKinney et al 2016 ); quantification of genomic inbreeding through runs of homozygosity ( Kardos et al 2016 ); and comparative genomics and genome evolution ( Brieuc et al 2014 ; Leitwein et al 2016). Linkage maps also provide an important resource in de novo genome assembly, as they provide information for anchoring sequence scaffolds and allow the prediction of gene locations relative to better annotated species ( Fierst 2015 ).…”

Quantitative trait locus analysis of parasitoid counteradaptation to symbiont-conferred resistance

“…With a single contributing locus, about 50% instead of the observed 36.51% of F3 sibships should have been unable to reproduce on H+ aphids, likely leading to a clearer separation of phenotypes by the genotype (Supplementary Fig. S3 ), as it is the case, for example, for an insecticide-resistance QTL in bed bugs (Fountain et al 2016 ). Moreover, a single-locus inheritance of the counteradaptation would likely have been detected in the additional analysis with offspring presence as binary phenotype, which detected no significant QTLs (Supplementary Fig.…”

Linkage mapping an indoxacarb resistance locus in Helicoverpa armigera (Lepidoptera: Noctuidae) by genotype‐by‐sequencing

“…Therefore, we were able to map the indoxacarb resistance gene within 1 centimorgan. A similar approach has been used for mapping fenvalerate resistance in H. armigera and pyrethroid resistance in the bed bug Cimex lectularius …”