What could be worse than living on a frozen tundra, you ask? Experiencing the world in only two tastes has got to be pretty rough. And when you're noshing down on fish day in and day out, only being able to taste things that are salty or sour has got to be a bummer too. But sadly, this is the life of the penguin.
In a new study published this week in the journal Current Biology, researchers with the University of Michigan revealed that in lacking the ability to taste things that are either savory or sweet, penguins may not be the best connoisseurs of food. Sadly, in spite of grubbing down on sushi all day, the flightless birds lack the sense for all things savory. And it's a puzzling discovery that has researchers wondering exactly why their genomes are missing such glaringly important functional genes.
"Penguins eat fish, so you would guess that they need the umami receptor genes, but for some reason they don't have them" coauthor of the study, Jianzhi "George" Zhang says. "These findings are surprising and puzzling, and we do not have a good explanation for them. But we have a few ideas."
After sequencing the genomes for Adelie and emperor penguins, Zhang and his colleagues found the shocking discovery that the penguins were lacking some basic taste genes. This sent the researchers on a genomic hunt, leading them to conclude that all penguin species lack functional genes for the receptors of sweet, umami and bitter tastes.
Though the researchers initially believed that the glaring disappearance of the genes may have been the result of mutations in the penguins' evolutionary history, they concluded that the loss is far more likely to be a product of their environment. Because all penguins trace their roots back to the cold waters of Antarctica, the researchers believe that it was likely the frigid temperatures that caused the loss of taste sensations.
Perplexed by the missing taste receptors themselves, Zhang and his researchers realized that eating cold food in a cold environment likely rendered the taste buds useless, since those for sweet, umami and bitter flavors are temperature sensitive. And though some penguins have moved to warmer waters, since all penguins trace their roots back to Antarctica, all of them are missing the taste sensations.
But don't feel too bad. After all, in a land of pure ice and no cream, who would want to be reminded of the sweet and savory sensations of ice cream anyhow?
