In today’s Academic Minute, Dr. Martin Hasselmann of the University of Cologne discusses the genetic process that determines the sex of honey bees.
Martin Hasselmann is a Heisenberg Fellow in the Institute for Genetics at the University of Cologne. He leads a group that studies genetic variation among honey bees and the molecular processes that influence their behavior and evolution.
Dr. Martin Hasselmann - Genetics Of Bee Sex
In a honey bee colony, usually one can find thousands of female worker bees, some male drones and a single queen, who lays the eggs. The question is how the different sexes arise? Male honey bees hatch from unfertilized eggs and females from those that ARE fertilized. In fertilized eggs, the condition of one single gene, the gene complementary sex determiner, or csd, regulates the development of females. The queen mates with different drones multiple times during her mating flight. Consequently, a random combination of two csd copies, so-called alleles are passed on to fertilized eggs. If these alleles are different enough - and that is the crucial information - they develop into a female. Two identical copies result into the development of diploid drones. These are, however, killed by worker bees shortly after they hatch.
So there is a strong advantage to possessing a different form of this particular gene, and previously, the total number of csd alleles was estimated at about 20. We have now detected a much higher diversity at this gene. We collected bees from different places in the world and identified up to 87 different alleles in our data set. Using an evolutionary model, we estimate that up to 145 csd alleles may exist. One region within csd represents a hot-spot with a high evolutionary rate giving rise to new csd alleles within short periods of evolutionary time.
Honey bees are among the most important pollinators in the world and the fitness of a bee population depends on, among other things, the genetic diversity of these csd alleles. Our new findings are therefore very important for beekeepers and will allow them to minimize the danger of diploid drone production by inbreeding which may happen in honey bee breeding programs.