FOR IMMEDIATE RELEASE: 3 JULY 2000

Contact: Jim Barlow, Life Sciences Editor
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217-333-5802
University of Illinois at Urbana-Champaign


CHAMPAIGN, Ill. -- A gene associated with the biological clock in many
organisms has revealed yet another
function. In honeybees, which live in a world with a distinct division of
labor, the gene is more active in the brains
of older bees, especially foragers whose jobs are outside the hive.

The new findings suggest that there are molecular connections occurring in
the brain that influence the division of
labor and the biological clocks of social insects, University of Illinois
researchers say. The study, published June
6 in the Proceedings of the National Academy of Sciences, is the first to
examine the period gene in a
developmental context.

"This paper implicates a clock gene in a function that is different than the
basic mechanism of the biological
clock," said entomologist Gene E. Robinson, director of the UI Bee Research
Facility. "This may go beyond
circadian rhythms. But we have no idea yet what causes the increase in gene
activity, nor do we know its
function. This is the first time that such developmental changes in the
activity of the period gene have ever been
detected."

Robinson's team chose to examine the period gene for its possible role in
the honeybees' complex, age-mediated
labor system, because it had been found to be involved in time-related
processes in fruit flies. Forager
honeybees, Robinson said, have a highly developed internal circadian clock
that guides their navigation, dancing
communication and nectar gathering. In addition, he said, their division of
labor is temporal -- a matter of timing
and aging.

In a study published in 1998, Robinson and colleagues looked for the rhythms
of life in a beehive. They found
that young bees shifted randomly between rest and work regardless of time as
they performed their duties of
feeding the larvae, while foragers only ventured from the hive during
daytime hours.

In the latest study, Robinson's team noted that levels of mRNA of the period
gene, a message carrier of active
DNA, rose and fell during the day in both young and old bees. This cyclic
activity is a signature of all clock
genes, including period. However, levels of mRNA were twice as high in older
bees and in precocious foragers
-- bees forced into foraging at an earlier than normal age. The latter
discovery, Robinson said, suggests an
association between foraging activities and high levels of period gene
activity.

The elevated levels, the authors wrote, "cannot be caused solely, if at all,
by increased chronological age,
foraging, flight, or exposure to the sun," as foragers confined to the
laboratory and isolated in darkness away
from their social environment for several days also maintained high levels.

###

Working with Robinson were Dan Toma, a graduate student in the department of
ecology, ethology and
evolution who cloned the honeybee's period gene, postdoctoral researcher Guy
Bloch, and Darrell Moore, a
visiting biologist from East Tennessee State University. The National
Institutes of Health, National Science
Foundation and the UI were among the agencies that funded the research.