Source: University of Toronto
Fruit fly 'hibernation' linked to single important gene
October 16, 2006
potential to develop new agricultural and medical techniques
by Sonnet L’Abbé (about) (email)
University of Toronto at Mississauga scientists have isolated a gene
responsible for whether or not fruit flies ‘overwinter’ – that is, whether
they will stop reproducing and go into a rest state as days get shorter –
uncovering new data that could impact research in fields ranging from
agriculture to medicine. Their work was published today in the Proceedings
of the National Academy of Sciences.
Karen D. Williams, a Ph.D student in biology at the University of Toronto at
Mississauga, with professor Marla Sokolowski, Canada Research Chair in
Genetics and her team, crossed overwintering fruit flies from the Windsor,
Ontario area to flies from the southern states, and found a gene responsible
for the arrested development trait. The same gene is also involved in
insulin-signalling, a process linked to diabetes and obesity in humans.
Fly overwintering is also known as diapause, a temporary halt in
reproduction or development, and is also found in other insects, animals and
plants. During diapause the organism goes into ‘sleep mode’ in biochemical
reaction to a change in surroundings.
"Arrests in development are widespread – insects enter diapause, animals
hibernate, some worms form dauer larvae," says Sokolowski, "but little is
known about the genes and cellular mechanisms involved."
The discovery is particularly important because it is another example in a
growing body of literature that suggests that individual genes can be
responsible for major variations in adaptive traits. This data, showing the
large effect of a single gene, counters a popular early genetic model that
suggests that all naturally varying traits in populations exist due to the
accumulation of the small effects of hundreds of genes over time.
"The genetic analysis that’s done in the paper is actually very difficult to
do because we didn’t break the DNA and make mutants, we looked at normal
differences in animals found in nature. That’s part of the reason it’s an
exciting paper," says Sokolowski. "We’re finding a gene for normal
individual differences that are out there in the real world."
The team’s finding is also exciting for its potential to help develop new
agricultural or medical techniques. Understanding of insect diapause is
important for the use of biological control agents in farming, for the
genetic modification of plant crops to resist infestation, and for
manipulation of arrested cells in mammals. The genetic discovery may also be
a doorway to new understandings of human seasonal disorders involving
metabolism and food intake.
Professor Marla Sokolowski, Department of Biology, University of Toronto at
Mississauga, 905-828-5326; e-mail: email@example.com