Scientists Use Bee Genes to Understand Behavior
SUSAN STAMBERG, host:
Some scientists are abuzz. I'm sorry, but they have determined the complete genetic sequence of the honeybee. Researchers, now these days, are probing some mysteries of the bee's existence, such as how a bee's genes control its behavior.
NPR's Joe Palca has more.
JOE PALCA: Quick biology refresher: DNA is a long double-stranded molecule. Along each strand are letters; or more properly, base pairs. The sequence of the letters tells you about an animal's genetic makeup. The totality of the letters makes up the animal's genome.
Professor KIM WORLEY (Genome Sequencing, Baylor College of Medicine): To sequence a genome, we start by chopping it into little pieces.
PALCA: Kim Worley, of Baylor College of Medicine, is one of the leaders of the consortium that sequenced the honeybee genome.
Prof. WORLEY: The pieces of sequence are usually on the order of 800 base pairs or so.
PALCA: An automated sequencing machine spits out the sequence for each piece. Worley says there are about 300 million letters, or base pairs in the honeybee genome. And remember, each little piece is only about 800 letters.
Prof. WORLEY: So there's a lot of little pieces that need to go together to get the whole genome put together.
PALCA: But that's what Worley and colleagues were able to do. Their complete honeybee genome sequence appears in the journal Nature.
Entomologist Gene Robinson, at the University of Illinois, Urbana-Champagne, says there are a number of reasons scientists are interested in the genes of honeybees.
Professor GENE ROBINSON (University of Illinois, Urbana-Champagne): They are really important in the environment. They are premier pollinator on earth, so in the United States alone, some 10 to $20 billion worth of food per year is attributable to their pollination activities. And then, in the biological sciences, they're important models in a variety of different fields.
PALCA: One of those fields is the genetics of behavior. Bees have a complex social organization. Robinson says with the genome sequence in hand, scientists can study how genes change their activity depending on what a bee is up to.
Prof. ROBINSON: We've compared the brains of nurse bees and foragers, and find 40 percent of the genes show differences in activity. Forty percent, which is a striking number, especially when you think that a nurse will grow up and become a forager.
PALCA: Robinson says a honeybee's gene switch on and off depending on what the bee is doing. In other words, genes are responding to the bee's environment.
Prof. ROBINSON: Just as behavior is dynamic, just as the brain is dynamic, also the genome is dynamic.
PALCA: Robinson's study of the genetics of a bee's brain and behavior appears in the journal Science. Also in Science is a paper by Charles Whitfield, of the University of Illinois, Urbana-Champagne, that uses the genome to investigate where the first honeybee came from. It turns out that, like humans, honeybees came out of Africa. But when Whitfield and his colleagues compared the genetics of two subspecies of honeybee - one from Eastern Europe and the other from the West - they found something surprising.
Professor CHARLES WHITFIELD (University of Illinois, Urbana-Champagne): Those two groups were genetically very distant from each other. In fact, each of those groups was more similar to African honeybees than they were to each other.
PALCA: Whitfield says the best way to explain this is, two separate ancient exoduses, one that headed toward Western Europe.
Prof. WHITFIELD: Probably via Morocco and Spain. And you've got one that got into Eastern Europe. And that one probably got there through the Near East.
PALCA: There was a third major exodus of honeybees out of Africa; that one occurred quite recently. In 1956, the so-called African, or Killer honeybee, was brought to Brazil. And those honeybees have been spreading their genes northward ever since.
Joe Palca, NPR News, Washington.
STAMBERG: Steve, do you know how to scare a bee?
STAMBERG: Boo, bee.
(Soundbite of laughter)
INSKEEP: Okay. Okay. Fine. Fine. Fine.