Genome Research has devoted this month's issue to studies that provide insight into the biology of the honey bee (Apis mellifera). The issue will appear online and in print on October 26, concomitant with the publication of the honey bee genome sequence in the journal Nature.
Since its split from the bumble bee 60 million years ago, the honey bee has evolved the highest rate of recombination--the process by which genetic material is physically mixed during sexual reproduction--of any known animal. In their Genome Research article, Dr. Martin Beye and his colleagues relate the sequence features of the honey bee genome to this strikingly high recombination rate.
Beye's team found an average of 5.7 chiasmata (crossovers) per chromosome in honey bees, while closely related species (bumble bees and parasitic wasps) as well as more distantly related species (fruit flies, worms, and humans) exhibited, on average, only 1.6 chiasmata per chromosome. The researchers dismiss the copious crossovers as necessary for stabilizing the chromosomes and, instead, propose an evolutionary theory to account for their findings.
"The honey bee has a small breeding population because the queen is the only reproductive female in the colony," explains Beye. "The increased recombination rate boosts the genetic diversity in the honey bee population, which in turn speeds the evolution of more selectively advantageous traits. This could help slow the spread of parasites in colonies, for example, or provide a basis for task specialization, leading to an increase in social complexity, colony performance, and fitness."
Martin Beye, Ph.D.
Heinrich Heine Universitt Dsseldorf, Germany