Scientists unravel bee DNA
Bees communicate by performing dances.
LOS ANGELES TIMES
Scientists have unraveled the DNA of the western honey bee, a feat that researchers say could help illuminate the genetic underpinnings of social behavior.
An international team of nearly 200 scientists reported last week that they have identified 10,157 genes. That's fewer than contained in the genomes of the fruit fly, mosquito or silkworm but nonetheless sufficient to produce the only nonprimate species capable of communicating through a symbolic language.
The genome of Apis mellifera was published in the journal Nature, along with a series of articles in Science, Proceedings of the National Academy of Sciences and other scholarly journals.
"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 consortium that carried out the sequencing and director of the neuroscience program at the University of Illinois at Urbana-Champaign.
"We hope to extrapolate the biology to humans," added Saurabh Sinha, a computer science professor at UIUC who led one of the companion studies about genes involved in social behavior.
A typical honey bee begins in the hive, caring for eggs and larvae. After about two or three weeks, environmental cues from the colony turn on thousands of dormant brain genes and silence thousands of others. That prompts the bee to leave the nest in search of nectar and pollen, the researchers reported.
What dances mean
When a new food source is discovered, returning bees perform a so-called waggle dance to tell other hive members how to find it. If more foragers are needed, bees execute a "shaking dance," and if they need to recruit more food handlers, they initiate a "tremble dance."
Honey bees use pheromones to keep track of the social standing of fellow colony members and differentiate between kin and outsiders. Compared with other insects, the researchers found, honey bees have more genes devoted to sensing smells. But they have fewer genes for taste, perhaps because they tend to eat where fellow bees ate and therefore don't need as much sensitivity for detecting poisons, scientists theorized.
In the project, which was funded with 6.9 million from the National Human Genome Research Institute, part of the National Institutes of Health, and 750,000 from the U.S. Department of Agriculture, researchers were surprised to find that honey bees have relatively few genes for regulating immunity despite living in cramped quarters where disease could easily spread. Perhaps the highly structured bee society works to minimize incursions from parasites and pathogens, possibly by having members groom each other, Robinson said.
Bees and humans
The researchers also discovered that many bee genes have more in common with humans than with fruit flies, such as genes involved in regulating circadian rhythms and the chemical method used to regulate gene expression.
By analyzing 1,136 genetic markers that varied among 341 honey bees, scientists concluded that the species originated in Africa -- not in Asia, as originally thought -- and spread to Europe and Asia in two distinct ancient migrations. They were brought to the New World by European explorers beginning in 1622.
The subspecies known as the African "killer" bee was imported to Brazil in 1956 to boost honey production and since has spread throughout the Americas, displacing their European counterparts.
Scientists use honey bees to study human health, including immunity, allergic reaction, antibiotic resistance, development, mental health, social behavior and longevity. Bees are also important for their role in pollinating billions of dollars worth of crops.