12/19/2023 0 Comments Human and chimpanzee feet joints![]() candidate in human evolutionary biology and lead author on the paper. “Later, as human populations expand and drift, you start getting these genetic variants that slightly modify how the knee is shaped or how the knee is maintained,” explained Daniel Richard, a Ph.D. What variation persisted likely didn’t substantially matter at that time. The highest-functioning knees would have been selected, reducing variation in knee shape over time by decreasing the genetic variation in the switches that control the joint’s formation. What they found reflects what Capellini suggests indicates “positive selection”: evidence that this new knee gave the fledgling bipeds an evolutionary advantage. ![]() Studies say stopping can delay or even prevent the most severe form of ailment To that end, they searched for traces of specific regulatory switches, pieces of DNA “responsible for turning on and off the genetic material that make the knee a human knee.” “We wanted to know whether or not we could see signs of ancient evolution - ancient selection - in the regions of the genome that specifically sculpt the knee,” said Capellini. To understand how this complex mechanism developed, researchers looked for evidence of accelerated natural selection: the series of mutations helped us walk upright. ![]() “As you can imagine, when you’re designing a part for an airplane, you don’t want to stray too much,” Capellini said. With such a specific task - and limited by its origins in the older primate knee - the optimized bipedal knee developed what is known as a constrained morphology, that is, it did not allow much variation. The cells in the joint and the shape of the joint had to change to accommodate those new forces.” All our weight is being transmitted through our hips and our knees down to our ankles. “Going from a quadruped to a biped changes the force distribution. “From an evolutionary standpoint, the primate knee went from something that accommodated the forces of walking on four legs to placing all the weight on two legs,” he said. Wolf Associate Professor in the Department of Human Evolutionary Biology and the paper’s corresponding author, explained it in terms of a burden our knees literally endure. In a new paper published in Cell, “ Evolutionary Selection and Constraint on Human Knee Chondrocyte Regulation Impacts Osteoarthritis Risk,” researchers exploring the genetic features that help make this sophisticated joint possible found that the regulatory switches involved in its development also play a role in this partially heritable disease, which afflicts at least 250 million people worldwide. ![]() However, as the human lifespan extended, the flaw in the design emerged: pain, in the form of osteoarthritis. The joint, which evolved fairly rapidly from our common ancestor with the chimpanzee to accommodate bipedalism, likely contributed to our success as a species. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |