SCIENCE
NEWS
This Week
Genome
Buzz
Honeybee DNA raises
social questions
Scientists have officially unveiled the DNA
code of the western honeybee, the first
genome to be sequenced for an animal with
ultrastratified societies.
The bees are among the select species in
which a few individuals reproduce while
others in the colony raise the young and do
the chores.
The honeybee genome, the whole
sequence of its DNA building blocks, shows
some patterns that fit old ideas of social living plus some patterns that demand new
thinking, reports the consortium of bee-genome researchers.
The scientists report the genome’s highlights in the Oct. 26 Nature. More than
40 other analyses also appeared in journals including Science, the Proceedings of
the National Academy of Sciences, and
Genome Research.
“The sequencing of the honeybee
genome is unquestionably a historic
event,” comments Ben Oldroyd, a bee spe-
cialist at the University of Sydney in Australia.
The honeybee’s genome is the fifth to be
sequenced among insects, says Gene
Robinson of the University of Illinois at
Urbana-Champaign, a founding member
of the bee consortium. Geneticists first did
the lab fruit fly, Drosophila melanogaster,
and have since published reports on
another fruit fly species, the malaria mosquito, and the silkworm.
Among the novelties of the honeybee,
Apis mellifera, are its 170 genes for odor
receptors. The lab fruit fly has 60. “Social
life relies heavily on smell,” notes Robinson.
The bees, however, carry fewer known
immune system genes than the lab fruit fly
or malaria mosquito does. That was a surprise, says Robinson, since social life brings
extra risks of disease. Perhaps the honeybees compensate through particularly
healthful behaviors, such as grooming, or
perhaps some undiscovered genes drive
their innate immunity. “Either way, it will
be interesting,” says Robinson.
The honeybees’ famous royal jelly, the
food that sets a larva on the road to becoming a queen instead of a worker, comes from
proteins encoded by nine genes. The
researchers compared them with other
species’ genes and concluded that they
evolved from the so-called yellow gene,
which plays a role in fruit fly pigment, for
example.
In several groups of genes, such as those
for circadian rhythms, the honeybee looks
more like a vertebrate than the other
sequenced insects. The honeybee also uses
a full set of vertebratelike genes for enzymes
that regulate the action of other genes. Lab
fruit flies use a different system for regulating genes.
Even though honeybees differ radically
from fruit flies in their sex determination—
honeybee males develop from unfertilized
eggs and thus have only one copy of each
chromosome, whereas a fruit fly male gets
chromosomes from both a father and
mother—the two species’ sex-related genes
still show similarities.
Honeybees can perform remarkable feats
of learning and memory, says Adrian Dyer
of Monash University in Clayton, Australia.
He predicts that having the honeybee
genome in hand will spur “insight into how
complex behavior patterns can arise in
organisms with relatively simple brains.”
The new research should also boost efforts
to breed hardier honeybees, says Robinson.
He says that U.S. commercial honeybee populations have shrunk by up to a third in
the past 20 years, mostly because of an
invasion of bee-killing mites. —S. MILIUS
Med-Start Kids
Pros, cons of Ritalin for
preschool ADHD
R. MALESZKA
BEE INSIGHTS A western honeybee worker tends larvae, one of the social behaviors that
makes the insect’s sequenced genome so intriguing to biologists.
The stimulant known as Ritalin displays
pluses and minuses in preschoolers receiving the drug for attention-deficit hyperactivity disorder (ADHD), according to the
first large, long-term study of the drug’s
effects in such youngsters.
In many cases, low doses of the medication, methylphenidate, safely quelled 3-to-
5-year-olds’ ADHD symptoms, the gov-ernment-funded investigation revealed.
However, preschoolers more often developed stimulant-related side effects, including irritability, insomnia, and weight loss,
than older children with ADHD have in
prior studies.
Preschoolers with ADHD also experienced
slowed growth rates during the year after
starting stimulant treatment, reports a team
led by psychiatrist Laurence Greenhill of the
New York State Psychiatric Institute in New
York City. By the end of the 70-week study,
these children were one-half inch shorter in
height and weighed 3 pounds less than
expected, based on average growth data for
same-age U.S. children.
“Preschoolers with severe ADHD symptoms can benefit from [Ritalin], but doctors should weigh that benefit against the
potential for these very young children to
be more sensitive than older children are to
the medication’s side effects,” Greenhill says.
His team presents its findings in five
papers published in the November
Journal of the American Academy of Child and
Adolescent Psychiatry.
The researchers conducted the six-site
study to address growing concerns over the
safety and effectiveness of prescribing Ritalin
to treat ADHD in preschoolers. Several
sources of medication data have indicated
that the number of prescriptions for Ritalin
and other stimulants to 2- to 4-year-olds
began increasing sharply around 15 years
