Like sweets? You're more like a fruit fly than yo...( PHILADELPHIA (March 17 2008) -- Acco...)

PHILADELPHIA (March 17, 2008) -- According to researchers at the Monell Center, fruit flies are more like humans in their responses to many sweet tastes than are almost any other species.

The diverse range of molecules that humans experience as sweet do not necessarily taste sweet to other species. For example, aspartame, a sweetener used by humans, does not taste sweet to rats and mice.

However, fruit flies respond positively to most sweeteners preferred by humans, including sweeteners not perceived as sweet by some species of monkeys.

The findings, published in the current issue of the journal Chemical Senses, demonstrate the critical role of environment in shaping the genetic basis of taste preferences and feeding behavior.

Humans and flies have similar taste responses because they share similar environments and ecological niches, not because their sweet receptors are similar genetically, notes senior author Paul A.S. Breslin, PhD, a Monell sensory geneticist. Both are African species, both are omnivorous, and both historically are primarily fruit eaters.

To compare how molecular structure is related to sweet taste perception in humans and flies, the Monell researchers evaluated how fruit flies respond to 21 nutritive and nonnutritive compounds of varying molecular structure, all of which taste sweet to humans.

Breslin and lead author Beth Gordesky-Gold, PhD, used two behavioral tests to evaluate the flies responses to the various sweeteners.

The taste reactivity test measures whether a fly extends its feeding tube, or proboscis, to consume a given sweetener. In addition, a two-choice preference test evaluates the flies responses to a sweetener by measuring whether they consume it in preference to a control solution (usually water).

The Monell researchers found that fruit flies and humans both respond positively to the same broad range of sweet-tasting molecules.

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