![]() “Indisputably, flourishing of birds is one of the great events in the history of life on Earth. “What my lab does fundamentally is, we look around frankly at the modern world and we look at extant biodiversity and we try to identify those vertebrates that have had a disproportionate impact on the modern world and the tapestry of life on the face of the planet,” he said. The technology the research team used is called CLARITY, Griffin said, and consists of three steps: making the embryo transparent, then staining it so the nerves, muscles and bones glow under a laser, and finally viewing it through a confocal microscope.īhullar said he considers himself a historian as well as a scientist. “The assumption was that there was nothing on Earth that has that particular structure at any point during its lifetime,” Bhullar said. One is the pubic boot, which is at the end of the pubic bone, and which scientists thought had disappeared 65 million years ago. Other structures in the bird embryo also resemble those of dinosaurs, but they “appear and then disappear, so they’re transient,” Bhullar said. “They get thrown in an attic somewhere and left to degrade.” Usually, genetic instructions that are no longer used “get scrambled because there’s nothing operating to stabilize them,” he said. Since this is true, that means that every bird genome still has the instructions to make “dinosaur-like hips,” Bhullar said. “In the lifetime of every single bird in the little microcosm that is the egg, there is a passage through stages that resemble those of their dinosaurian ancestors.” “We had found previously that was the case … for the bird beak, but it turns out not to be the case for the pelvis,” he said. He expected changes that reach so far back in evolutionary history to occur early in the embryo’s development. As the Welsh Dragon shows, smaller dinosaurs were around 200 million years ago in the Late Triassic period. However, the miniaturization didn’t necessarily occur after the T-rex. “You’ve got to change instructions during assembly,” Bhullar said. Part of the supporting evidence for this is that the head of birds, such as a chicken, bear a resemblance to infant dinosaurs. ![]() “The earlier you mess up a process, the more messed up it will be in the end.”Īs vertebrates develop from a single cell, the genes tell the cells how to change and what to become: skin, bone or brain. “My expectation at least was that most of these alterations would be present early on,” Bhullar said. The change from dinosaur to bird hip so late in its development also is unusual. That contrasts with lizard legs, for example, which are “not unmuscular, but they’re kind of cylindrical and skinny.” Chicken thighs, on the other hand, have meat on the bone. “In birds, it’s expanded beyond other dinosaurs,” Bhullar said.
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