Hand, not a hand is a forked fin evolutionary miracle – Science and technology Sohu www.h4610.com

Hand, is not the hand, the bifurcation of the fin: an evolutionary miracle – Sohu technology Author: Lucorta92 editor: Calo when you skillfully move the mouse point to open the link, you may not realize that in this common action, you have to use one of the most unique tools: the human world hand. Fine structure of the hands so that people can be the brain into a reality, to change the environment, the emergence of civilization. Our hands come from 2004, paleontology Neal · Shu Bin (Neil Shubin) and Ted · Kohler (Ted Daeschler). The team found a strange fossils in northern Canada Ayers mill Island: it is like a fish have gills and fins, but also has a neck and front flippers the skeletal structure similar to the arm…… This is called Tiktaalik (Tiktaalik) creatures live in about 375 million years ago, the late Devonian is transitional species between fish and early quadruped animal. Leave the water and land on it and touch with its similar species in the journey, a long time such as delicate as the evolution of the sculptor left in their genome imprinting. In the end, the foot of the earth’s four legs appeared on the planet. And one of them will grow both hands at the end of the forelimb. Tiktaalik fossil and restoration model. This creature’s anterior fin has evolved a wrist like structure. Photograph: Beth Rooney uchicago.edu Tiktaalik restoration source: between fish and tetrapod evolution of the vacancy due to the discovery of Tiktaalik fill a. However, the limbs and fins in the development of the relationship is still unclear. The development of biological evidence that the fin fin and a phalanx of quadruped animal forelimb distinct developmental pathways, composed of bony fin membrane (dermal bones), their bone formed directly in connective tissue; and the quadruped phalanges are bones (endochondral bones), which is the first formed cartilage in the connective tissue, then the cartilage destruction and the formation of. For this reason, scientists have long believed that fingers are a kind of structural innovation that has no predecessor. In the mouse paw (left), which refers to the wrist bones and cartilage are bone, and in the zebrafish fin (right), fin base bone cartilage bone, but the bone is bone fin membrane. It is not clear how the changes from the membrane to the cartilaginous changes occur in the evolution of fish to the early tetrapods. Source: reference [1], however, this view has now been shaken. With the help of CRISPR gene editing technology, Shubin’s team found that the fin and fingers may is the same structure, they share a set of genetic tools, also shared a development history. Their paper [2] has recently been published in the journal Nature (Nature) d相关的主题文章: