LONDON: Scientists have sequenced the genome of the honey bee, which has given new insights into its African origin, the evolutionary transformation it has undergone and its capabilities of memory, language and evolving a hierarchical system.
The Honeybee Genome Sequence Consortium, which undertook the research (costing $7.6 million and starting in 2003), reports about what is describes a social revolution "encoded subtly" within a genome possessing more than 10,000 genes. The findings of the study are reported in the latest issue of the journal Nature.
While extensive studies have been done on the social structure followed by honey bees and on the hierarchical system where the queen bee is the center, surrounded by the male drones capable of reproduction and the female worker bees, which are responsible for food gathering, defense and house-keeping, there has been little knowledge on the genes that created such diverse behavior in the inhabitants in the same hive, their memory powers and the ability to use language.
A co-leader of the group that carried out the sequencing and director of the neuroscience program at the University of Illinois at Urbana-Champaign Gene Robinson says honey bees are important models to study the regulation and evolution of life in a society, especially social behavior itself.
He said honey bees are also valuable to scientists as models for research organisms. They are used in biology and biomedicine to study many diverse areas, including allergic disease, development, gerontology, neuroscience, social behavior and venom toxicology. "Because they live in intricate societies, we can view the traits that honeybees exhibit through a prism of extreme sociality."
Saurabh Sinha, professor of computer science at the University, who led a companion study on genes involved in social behavior, said the team now hopes to extrapolate the biology to humans.
George Weinstock, a leader of the consortium, said the research work has been able to identify genes that protect the bee from toxins, a useful tool in understanding the insect's sensitivities or resistances to the pesticides that some blame for the declining fortunes of bees and other U.S. plant pollinators.
The study finds that bees have many genes for detecting odors but relatively few for taste receptors or immunity. Bits of RNA appeared to show different on-off patterns whether they are in queens or workers, hinting at a mechanism for retaining social standings.
The researchers also say as the evolution happened, honeybees gained a memory power to identify where nectar sources are and an ability to communicate the relative distance and direction of these sources with a "waggle dance." The researchers describe this as symbol language yet to be related to species beyond the primates.
A group among the scientists also used genetic variations among different honeybee subspecies to determine that the Apis mellifera lineage came from Africa and not Asia, as believed earlier, and spread to Europe and Asia through migrations.
The researchers have identified a 100-million-year-old amber-encased bee. One of the co-authors of the study, Bryan Danforth, an entomologist at Cornell University, said the tiny insect may well fill in a family tree that now contains about 16,000 species.
The new genetic information gleaned from the studies may not explain outright how the bees became social animals, how they developed memory and how they came to use language, but by comparing the genome with those of the other two insects that have been sequenced -- the fruit fly and a mosquito -- there will be possible conclusions, the scientists feel.
The researchers estimate that bees have around 10,000 genes, compared with 25,000 in humans and 14,000 in mosquitoes.
