IMAGINE A WORLD No bird barks. However, this could have happened at the beginning of Passeri’s evolution in the absence of the genetic alterations that occurred about 30 meters ago in order to give the songbird a proper name.
Birds evolved from carnivorous dinosaurs called theropods. Meat eaters don’t need to detect sugar like fruit eaters, for example. Genetic analysis of modern birds suggests that theropod ancestors have lost the ability to taste sweetness. But today, many birds eat nectar and fruit sugar-rich diets, so recognizing things as sweet is a useful attribute.And just published research Science Yasuka Toda of the University of Tokyo and Mode Baldwin of the Maxplank Institute for Ornithology in Seawesen, Germany, suggest that songbirds can certainly perceive sweetness. This re-evolved ability may have contributed to their success. That’s not a small issue, as almost half of the bird species currently alive are parsley.
Vertebrate taste receptor genes are usually found T1R1, T1R2 And T1R3.. The taste receptors themselves are formed from these protein pairs.The receptor for sweetness T1R2 And T1R3..But birds lack genes T1R2.. Probably lost by their theropod ancestors who didn’t need it. Experiments by Dr. Toda and Dr. Baldwin show how this loss has been reversed.
The first study of this pair, published in 2014, was on hummingbirds that eat nectar from flowers. Hummingbirds have been found to have regained their ability to taste sugar through genetic mutations. T1R1 And T1R3..Receptors formed in combination T1R1 And T1R3 Usually, it detects umami, which is a savory flavor peculiar to meat. In hummingbirds, these mutations also allow this receptor to detect sugars. Therefore, Dr. Toda and Dr. Baldwin wondered if that also applies to songbirds.
To find, they cloned T1R1—T1R3 We tested the response to receptors and sugar from various songbirds. All receptors they tested interacted strongly with sugar molecules from birds on sugar-rich and sugar-poor diets. This confirmed that, like hummingbirds, songbirds regained their perception of sweetness through genetic mutations. T1R1 And T1R3.. In contrast, the umami receptors cloned from Passeri’s sister group, Tyranni, interacted very strongly with the amino acids typical of meat, but not with sugar. Therefore, mutations in the songbird strain must have occurred after the passage and tyrant flycatcher strains diverged and before the passage itself began to multiply in the current breed.
Interestingly, when Dr. Toda and Dr. Baldwin investigated molecular modifications, T1R1—T1R3 When the hummingbird and passeri receptors detected sweetness, they found that they were completely different.However, both have made a number of changes to the foundation. DNA, Suggesting strong evolutionary pressure to optimize them. This pressure was probably the result of competition to fill a new ecological niche opened by the ability to recognize sweets as both edible and nutritious. And that was what brought about the current diversity of Passeri. It’s unclear how all of this is tied to the hilarious songs sung by many members of the group. It may be a coincidence. But if so, it’s fortunate for those who enjoy the song of birds. ■■
This article was published in the Science and Technology section of the printed version under the heading “Sweet Taste of Success”.