The article said that the latest research by scientists found that jellyfish with seemingly simple structure have many advanced genes with developed functions, some of which are the same as human genes. The discovery of these genes helps to reveal the evolution of animals 600 million years ago. This new scientific research achievement about the genetic results of jellyfish makes scientists who once underestimated them realize that jellyfish is not a remnant species in the evolution of early animals. When you see the jellyfish in the aquarium with your own eyes, you can easily understand why people describe it as a simple and primitive animal. Like its relatives anemones and corals, jellyfish are not complicated at all. It has no head, no chest and back, no left or right, and no legs and fins. It doesn't even have a heart. Its internal organs are more like a tube than a blind sac. Its mouth and anus have similar functions. It has no brain, only a set of diffuse neural networks. A fish or a shrimp can swim very fast once it sees a certain direction, but all the behaviors of jellyfish are always lazy and slow. Renaissance scholars once regarded jellyfish as plants. It was not until the18th century that naturalists reluctantly brought them into the animal kingdom. They defined coelenterates as marine animals "animal plants" similar to plants, that is, creatures between animals and plants. However, it was not until the19th century that naturalists began to understand that coelenterates developed from fertilized eggs, and their body parts were differentiated from primitive endoderm and ectoderm. Other animals, including humans and insects, have a third germ layer, that is, a mesoderm between endoderm and ectoderm, which eventually differentiates into muscles, hearts and organs that other coelenterates do not have. Recent new research has given scientists a new understanding of jellyfish and their relatives. Coelenterates, such as jellyfish, whose original structure seems simple, hide a series of quite complex genes under their simple and simple appearance, including some structures as complex as human genes. Dr Kevin J. Peterson, a biologist in Dartmouth, England, said: "The most surprising discovery is that the genes of coelenterates are more complicated than anyone thought. This kind of information has made many people turn around and realize that their views on coelenterates in the past were wrong. " The new discovery of jellyfish inspired scientists to put forward a new theory about how animals evolved 600 million years ago, and also attracted scientists to use echinoderms as a model to understand the human body. Unconventional research on coelenterates Fish, fruit flies and earthworms all have heads and tails, front and back, left and right. Scientists call bilaterally symmetrical animals, including humans, bilaterally symmetrical animals. On the contrary, the body design of coelenterates is simpler, and coelenterates seem to lack this complete symmetry. Jellyfish, for example, is a wheel-shaped symmetry that emanates from the central axis. Evolutionary biologists began to think that coelenterates were the remains of early animal evolution. The first animals may be spongy cell masses. Coelenterates seem to represent a new period, when animals have acquired the characteristics of simple tissues and nerves. The fossil record of animals seems to support this hypothesis. Many early animal fossils are similar to jellyfish or other coelenterates. Some researchers believe that the symmetrical body structure on both sides benefited from the Cambrian Big Bang about 540 million years ago. These symmetrical animals are no longer like their ancestors. Their heads can better feel their surroundings and control their swimming or crawling bodies. According to DNA, this mutation has been going on for more than one million years at a wide and regular speed called molecular clock. Therefore, Dr. Peterson and his colleagues made a new estimate of the survival age of coelenterates by studying their DNA. Dr Peterson estimates that the ancestors of coelenterates today lived about 543 million years ago. Therefore, this conclusion shows that the oldest fossil known as coelenterate is only 540 million years old. In other words, coelenterates did not appear in the tens of millions of years when bilateral symmetrical animals were born. Scientists began to study animals with bilateral symmetry in 1980s, and scholars uncovered the mystery of a series of genes that make up the bodies of animals with bilateral symmetry. Some genes are responsible for establishing the central axis of the body from beginning to end, while others are responsible for distinguishing between the front and the back. Humans and insects may look very different, but they share an almost identical version of the genetic toolbox, the genome. Studies have found that this gene evolved from animals with symmetry on both sides of our common ancestor. Dr Mark martindale of the University of Hawaii and his colleagues decided to study the genes of jellyfish and other coelenterates. Dr martindale's team chose a species named star anemone found off the coast of New Zealand for research, including how to cultivate anemones and investigate their genetic composition. It took a long time for the research to come to fruition. They found that anemones can not only survive in laboratory conditions, but also produce enough embryos for the study of artificial environment. Surprisingly, scientists have found that in bilaterally symmetrical animals, including humans, some genes that control embryo initiation are almost the same as those that determine the longitudinal axis of head and tail. Even more amazing, these genes are also responsible for opening the same head-tail pattern in bilaterally symmetrical animals. Further research shows that coelenterates also use other genes in the gene pool of bilateral symmetric animals, that is, the same genes responsible for the embryos of bilateral symmetric animals. For example, anemone embryos can also produce opposite faces from this gene. John, a biologist who works with Dr. martindale at Boston University? 6? 1R？ 6? 1Dr. finnerty said that at the molecular level, we still don't know many body regions of coelenterates. Dr Finnerty hopes to finally prove that the nervous system of coelenterates is particularly complex. He said that the current textbooks simply describe the nervous system of coelenterates as a neural network. He predicted that the research will prove that these seemingly simple neural networks can actually be divided into specialized regions like the human brain. These findings prompted Dr. Peterson to reconsider the position of coelenterates in the history of biological evolution. He said that these findings changed his view on the evolution of early animals. He has now put forward a new theory that coelenterates are not simple pioneers of the CAMBRIAN Big Bang, but only an extraordinary part of it, and their evolution is driven by the rise of animal food networks. In a paper published in Paleontology, Dr. Peterson and his colleagues pointed out that the same ancestor of bilaterally symmetrical animals and coelenterates was worms. Peterson estimates that the appearance of this ancient worm, which lived 600 million years ago, is a great progress in the evolutionary history of animals, because animals have changed from passively filtering tiny food to actively swallowing larger prey. Dr. Peterson said: "Once they start feeding on those microbial communities themselves, nothing can stop them." Some of these animals eventually began to eat another animal. Animals that can defend themselves are more likely to survive. One way to avoid being eaten is to make your body stronger, and the other way is to lay eggs in columns with water, instead of laying eggs on a flat bottom for other animals to eat. Early coelenterates fixed themselves on the bottom of the sea and grew upward, just like anemones and corals today. In the process of evolution, they abandoned the symmetrical body structure of their ancestors. At the same time, coelenterates have evolved their unique equipment: a cell can contain tiny sharp spines called stinger sacs, which can secrete toxins to paralyze prey and attack enemies. Dr. Peterson said that a new animal moves higher inside the water column, and some coelenterates have evolved into hunters who prey on them at the same time. Jellyfish is the product of this ultimate evolutionary form. The new understanding of coelenterates prompted us to begin to understand these animals better. It is expected that the Energy Department of the Joint Genome Association will complete the genome sequencing of anemones this year. Therefore, scientists have found genes in the genome of coelenterates that were originally thought to belong only to vertebrates. It has been proved that these genes did not actually originate from early vertebrates. They are even older and evolved from the same ancestor of coelenterates and bilaterally symmetrical animals 600 million years ago. Subsequently, they disappeared into the branches of bilaterally symmetrical animals, such as insects and nematodes, which have long been widely used as the focus of genetic research by scientists. Some scientists have pointed out that coelenterates are more suitable as models for human biological research than fruit flies to some extent. As its mysterious internal structure is revealed step by step, it is possible that watching jellyfish in an aquarium is more like looking at a human mirror.