By Eric Beech
WASHINGTON
(Reuters) - Inexplicably drawn to cake, ice cream or candy? It's
not just because they taste good. Scientists said on Sunday they
may have located the so-called sweet tooth gene, a finding that
could lead to new artificial sweeteners.
In two separate
studies, scientists at Harvard Medical School (news - web sites)
and the Mount Sinai School of Medicine in New York pinpointed
a gene in mice they believe is responsible for tasting sweetness
and, with the help of the recently completed mapping of the entire
human genome, were able to locate the equivalent gene in humans.
Scientists
hope to have definitive proof that gene T1R3 is truly the ``sweet
tooth'' receptor gene in several months, said Robert Margolskee,
who headed the Mount Sinai team and whose study was published
in the journal Nature Genetics.
Margolskee
said the finding, if proven, could help scientists design new
sweetener.
``Present
artificial sweeteners were developed pretty much at random and
by luck,'' Margolskee told Reuters. ``By having the receptor protein
that normally binds sugars and sweetener you should be able to
target more specifically better-designed molecules that will bind
and activate the receptor,'' he said.
Both studies
used so-called tasting and non-tasting mice -- ones that preferred
drinking sugar water and ones that showed less preference for
sweetness -- and examined differences in their genetic makeup
to locate the sweet receptor gene.
With this
knowledge and the fact that humans and mice are closely related
genetically, the researchers searched the human genome database,
which was completed last year, and found T1R3 as a likely candidate.
Proving T1R3
is the ``sweet tooth'' gene will require further experiments,
including implanting the mouse equivalent of the gene into non-taster
mice and to see if it causes them to show an increased preference
for sugar water, said Jean-Pierre Montmayeur of the Harvard team.
Both the Harvard
and Mount Sinai teams are working independently on such experiments.
Finding the
sweetness gene and examining genetic differences among people
could also have implications for diet and diet-related diseases
like diabetes, Margolskee said.
``There are
genetic differences among people the same way there might be among
the taster and non-taster mice and this might affect people's
individual responses to sweet foods and how much cake and cookies
and ice cream they eat,'' Margolskee said.
``This could
have an effect on their diet and risk of obesity and related diseases
like diabetes, but we don't have any evidence (of that) yet,''
he said.
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