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Hummingbirds reprogrammed umami receptor to taste sweet nectar
Hummingbirds reprogrammed umami receptor to taste sweet nectar

For birds that don’t have teeth, hummingbirds have quite a sweet tooth. Although they eat insects to get essentials like protein and fat, most of their diet consists of sugary nectar. This has puzzled scientists. Humans and other animals that prefer sweet tastes are able to recognize them thanks to a pair of sensory receptors known as TIR2 and TIR3. But birds don’t have the gene that codes for TIR2. How, then, do hummingbirds know that nectar and sugar water are sweet? Now, an international team of biologists and their colleagues think they have found the answer: Over millions of years, genetic mutations converted a receptor that used to help hummingbird ancestors detect...

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