For a long time it was believed that the feathers of birds were inherited from the dinosaurs. It is not yet clear how and when the feathered dinosaurs – who became the ancestors of today's birds – began to fly. Now, a group of scientists want to study the true origin of the feather. They also analyzed feathers of fossil birds.
Studies published in Acting at the National Academy of Sciences (PNAS) highlights how fur can develop from the days of the dinosaurs.
Scientists conducted research based on fossils from four winged small dinosaurs, which were scientifically known as Anchiornis huxleyi. They believe that ancient beings lived before Archeopteryx, the first species of birds recognized by scientists. The Anchyroni dynastor, the size of a fault, lived in China 10 million years before Archaeopterx.
This research was conducted by an international team of scientists from the Nanjing Institute of Geology and Paleontology in China, State University of North Carolina and the University of South Carolina in the United States.
"Modern bird feathers consist mainly of beta-keratin (β-keratin), a protein that is also found in the skin, claws, and beaks of reptiles and birds. The feathers are different from other tissues containing β-keratin because feathered proteins are modified in a way that makes them more flexible, "says study author Mary Schweitzer of North Carolina State University and North Carolina Museum of Natural Sciences.
"At some point during the evolution of the fur, one of the β-keratin genes experienced a wiping event, making the protein a little smaller. This elimination changes biophysics into something more flexible – a requirement for flying ability," he added.
"If we can determine when and in which organisms the deletion occurs, we will have a better understanding of when the flight develops during the transition from bird dinosaurs."
Yanghong Pan, one of the co-authors of the Nanjing Institute of Geology, examined the anihiro's anchors using high resolution electron microscopy as well as chemical and immunological techniques (the study of antigens, antibodies, and cell-mediated functions of host cell defense).
The researchers carefully looked at the fossilized Perki from Anchiornis and compared them with younger bird feathers and modern birds at the molecular level.
They used the same technique for studying the ancient feathers of the Mesozoic period – about 252 to 66 million years ago – and the price tag – 65 million last year until now.
Their analysis showed that the feathers have β-keratin and alpha-keratin, which are proteins that have all the vertebrates on the Earth, including mammals.
This finding surprised scientists, since alpha-keratin can be found only in small amounts in modern feathers. Interestingly, the team found that fossil feathers indicate that the wings went through a "removal process" that separated the feathers of other tissues.
The results show that during the transition to flight capability, the β-keratin gene is multiplied many times in the genome of many dinosaurs. When these animals developed, many additional copies were mutated in a shortened form that allowed the flight.
This allows pillow dinosaurs, such as Archaeopterx, to have the ability to fly about 150 million years and to exhibit modern birds.
Flying ability is an "expensive" ability, said Schweitzer. There must be many "evolutionary reasons" to confirm this. So the discovery of feathered dinosaurs does not automatically indicate that species can fly.
The researchers say the Anchiornis feathers were not convenient for flying because they were too short. But it is a transitional phase in the evolution of fur to fly.
"The molecular clock, which scientists use as a benchmark for evolution and genetic divergence, predicts that deletion, and hence functional flight feathers, has evolved around 145 million years," he added.
The molecular clock is a way of molecular evolution, which uses the restriction and the comparison of fossil motions with molecular changes to lock the geological history of time, to deviations between two species or other taxa.
Schwitzer added that Anchiornis is millions of years older, but has a shorter protein form.
This study shows that dating fossil data can improve the discovery of molecular clocks and make the findings more precise. It allows scientists to determine the time for genetic events in the transition of dinosaurs to birds.