NANJING, January 29 (Xinhua) – Although dinosaurs are generally believed to be the ancestors of modern birds, it is largely unknown when and how evolution has taken place. However, a recent study by an international team of researchers has revealed a new light on the mystery.
The researchers carried out molecular analyzes of feathers from Jurassic rain fossil dinosaurs, fossil birds and modern birds, and found that the key proteins that make up the feathers became more thin and more flexible as the dinosaurs without a flight were They turned into flying birds.
The study, published in the Acts of the National Academy of Sciences (PNAS) on Tuesday, was conducted by a group of Chinese and American scientists from 2016.
The team used electronic microscopy and chemical analysis to examine and compare the molecular structure of the flight feathers of Anchiornis, a plunged dinosaur that dates to about 160 million years old and the current chicken.
It was discovered that chicken feathers were mainly composed of β-keratin, a structural protein that was commonly observed in skins, claws and beaks of modern reptiles and birds. It provides the birds with flexibility, elasticity, strength and other biomechanical properties necessary for the flight.
Although β-keratin was also found in Anchiornis feathers, feathers are dominated by a thicker and more rigid protein, α-keratin, which makes them unsuitable for the flight.
"It suggests that the feathers of the first completed dinosaurs were not used for the flight, but only for warmth and personal defense," said the leading scientific scientist, Pan Yanhong, a researcher at the Nanjing Institute of Geology and Palaeontology with the Chinese Academy of Sciences.
The researchers further examined fever fossils from birds, including 130 million years of eoconfuciusornis and Yanornis 125 million years of age, and concluded that the amount of β-keratin in The feathers increased over time as the dinosaurs evolved birds.
The molecular structure of feathers found in a fossil of 20 million years old birds was discovered to be the same as in modern birds.
"The study shows that the molecular structure of feathers has evolved steadily," Pan said. "The transition from dinosaurs to birds was a complex process, and the change in the structural protein of feathers is a crucial step."