Project Scope Genetic Markers for Varroa Resistance (GVaR)
Project Target Selection of Varroa Resistant Honey Bees by use of Genetic Markers.
Current Status , Assumptions and Proposed solution- Problem definition
– Current solutions
– Expected future solutions, trends.
– Proposed solution
Selection of honey bees in a Varroa resistance breeding program is currently only possible by investigating the phenotype: measuring the actual Varroa resistance behavior (like removal of infested brood) or indirectly by measuring the infestation or growth of the Varroa population in a colony. Improving the methods for making these measurements are covered in other projects in this program. The selection of Varroa Resistant bees could be much easier if we would have a good understanding of the genetics involved and had molecular markers to identify those colonies with the right genetics.

Two groups (USDA Baton Rouge, Hohen Neuendorf) are working on the development of a marker test and have been able to identify areas on two chromosomes connected to Varroa Sensitive Hygiene (VSH) behavior by mapping a population of bees. In those areas several candidate genes have been identified as potential targets for a reliable Marker test.

The current tests were developed in a specific Varroa resistant population (with its own genetic background). Once the tests would become more reliable and more precise in these colonies, it will be necessary to validate and understand the application in different lines of honey bees with different genetic backgrounds.

The current approaches already being pursued in Baton Rouge and Hohen Neuendorf could benefit from extra resources and funding.

The University of Wageningen, with knowledge of insect behavior and genetics, will start student projects to gain experience in this field with the purpose of supporting the projects in Hohen Neuendorf and Baton Rouge. Once molecular markers become available from these institutes, validation and adaptation to the lines used in the selection program in the Wageningen UR and Arista Bee Research can then be performed.

Science & Technology
– Target Technology: available, required
– Approach, Methodology, Tools
The basic technology needed for developing a marker test is available. For this marker test worker bees which show the hygienic behavior are compared to worker bees which do not show the hygienic behavior of removing Varroa mites from the brood. By investigating the differences in binding of large quantities of different small pieces of DNA, single-nucleotide polymorphism (SNP’s), genes and regions can be identified that might be responsible for this behavior, the quantitative trait: the Quantitative Trait Loci: ” QTL’s” .
Project Evaluation
– Potential value
– Probability of success
The availability of a molecular markers for VSH behavior would be a major breakthrough for the breeding program of Varroa resistant honey bees, especially if such markers were applicable for different strains of honey bees. So the potential value is very high. The development of markers for any behavioral trait is, however, a very laborious and risky area of research. Two institutes have relatively few resources available (total 2 FTE) with which they have reached already promising results.
Project Planning & Resources
– Planning
– Resources & Partners
To make more and quicker progress in developing a marker test for VSH behavior, extra resources are needed. When funding becomes available, extra resources could be made available to the established projects in Baton Rouge and Hohen Neuendorf. In the Laboratory of Genetics at the University of Wageningen, supporting activities are planned with BSc and MSc students. With the extra resources, new SNPs and better defined QTLs could be produced. Furthermore, additional research should be started to get a better understanding of the functions of the identified target genes and their presence in different strains of honey bees with different levels of VSH. More capacity in this area of research will make a reliable marker test quickly available to institutes and bee breeding communities all around the world.