ARS | Publication request: A Genome Wide Genotyping Study To Find Candidate Genes That Influence Varroa-Sensitive Hygiene (VSH)

Submitted to: Cold Spring Harbor Meeting
Publication Type: Abstract Only
Publication Acceptance Date: April 8, 2011
Publication Date: May 8, 2011
Citation: Tsuruda, J.M., Harris, J.W., Bourgeois, A.L., Hunt, G.J. 2011. A Genome Wide Genotyping Study To Find Candidate Genes That Influence Varroa-Sensitive Hygiene (VSH). Cold Spring Harbor Meeting. 66.

Technical Abstract: Varroa parasitism of honey bees is widely considered by apicultural researchers to be the greatest threat to beekeeping. Varroa-sensitive hygiene (VSH) is one of two identified behaviors that are highly important for controlling the growth of Varroa mite populations in bee hives. Bees exhibiting this behavior uncap and/or remove pupae from infested cells, thereby suppressing mite reproduction. We conducted a study to look for associations between phenotype (VSH behavior) and genotype in order to map quantitative trait loci (QTL) and find candidate genes that influence VSH behavior. High and low-VSH lines were crossed to produce an F1 hybrid queen, which was then crossed back to the high-VSH line using a single haploid male. The workers of this backcross served as the mapping population; individuals were observed for VSH behavior (uncapping cells or removing infested pupae) and genomic DNA was extracted for 240 individuals. The genomic DNA of the F1 queen was sequenced with the ABI SOLiD sequencing system and the sequences were then aligned with the honey bee genome. We identified over 9000 SNPs within genes that were heterozygous and would therefore be informative for following the segregation of alleles in the backcross mapping population. Probes were designed for 1536 SNPs and the GoldenGate genotyping assay (Illumina) was used to genotype 240 individuals from the backcross family. The genotypes for the 1348 informative SNPs were used to construct a high-resolution genetic map using JoinMap software. Interval mapping using MapQTL software identified one major QTL and one suggestive QTL. The 95% confidence interval for the major QTL region contains relatively few genes and includes a D2-like dopamine receptor, Dop3 (GB14561). This type of dopamine receptor has been previously shown to mediate aversive and olfactory learning, which are necessary for identifying mites and/or infested pupae within brood cells. These results allow for future screenings for up- and down-regulation of candidate genes that influence Varroa resistance and allow for the possibility of marker-assisted selection for the VSH trait in breeding programs.