Scientists map honeybees' genome

Researchers have pieced together the genetic blueprint for the honeybee, uncovering clues that point to an African origin and to a remarkable evolutionary transformation in an insect known for its memory, symbolic language and hierarchical caste system.

The honeybee has enjoyed a reputation as a master pollinator and honey producer. Yet scientists have marveled at the stark divisions of labor that separate the offspring-producing queens, sperm-yielding male drones and female worker bees that assume the defense, housekeeping and food-gathering responsibilities.

How, researchers wondered, could the same set of genes produce such radically different behaviors among hive inhabitants — especially in insects whose tiny brains possess only one-millionth the number of neurons as human brains?

The switch from a solitary to colony-focused lifestyle required nothing less than a "revolution at the genomic level," writes Harvard biologist Edward Wilson in today's issue of the journal Nature. In the same publication, The Honeybee Genome Sequence Consortium reports on the social revolution "encoded subtly" within a genome possessing slightly more than 10,000 genes.

"Honey bees are important models to study the regulation and evolution of life in a society, especially social behavior itself," said Gene Robinson, co-leader of the group that did the sequencing and director of the neuroscience program at the University of Illinois at Urbana-Champaign (UIUC).

"We hope to extrapolate the biology to humans," added Saurabh Sinha, a computer-science professor at UIUC who led a companion study about genes involved in social behavior.

George Weinstock, a leader of the research consortium, wrote in an e-mail that the knowledge also may aid in understanding the genetic underpinnings of behaviors ranging from the unusual altruism seen among worker bees to the aggressiveness that characterizes African "killer bees."

He said the consortium also identified 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.

Bees, the study suggests, have many genes for detecting odors but relatively few for taste receptors or innate immunity. Small bits of RNA even seem to show different on-off patterns depending on whether they're in queens or workers, hinting at a mechanism for retaining social standings.

Somewhere along their evolutionary pathway, honeybees also gained a gifted memory for nectar sources and an ability to communicate the relative distance and direction of these sources with a "waggle dance," the only symbolic language yet found beyond the primates. The new genomic data, researchers say, could help reveal the basis for both traits.

Within a swarm of accompanying studies, a separate group used genetic variations among different honeybee subspecies to suggest that the Apis mellifera lineage arose in Africa — not in Asia, as originally thought — and spread to Europe and Asia in two ancient migrations.

They were brought to the New World by European explorers beginning in 1622.

And a research duo announced in the journal Science that they have discovered a 100-million-year-old amber-encased bee — by far the oldest ever found. Study co-author and Cornell University entomologist Bryan Danforth said the tiny insect may help fill in a family tree that now contains about 16,000 species. The discovery, he said, raises new insights about the possible co-evolution of early bees and the small flowering plants just beginning their expansion across a prehistoric landscape.

Material from the Los Angeles Times is included in this report.