Guizhou discovers 610 million-year-old embryo fossils reveal “chicken first or egg first”

Do you have chickens or eggs first? This is really the two ultimate problems that plague humanity! Recently, the Nanjing Institute of Geology and Paleontology of the Chinese Academy of Sciences, in collaboration with scholars from Britain, Sweden and Switzerland, discovered a 610 million-year-old embryo fossil “cage spine ball” in the Yan’an biota, documenting a key step in the evolution of animals from single-celled ancestors to multicellular ancestors, and is widely regarded by the scientific community as the key to solving this mystery.

Cage spine fossil sac preserved

“Eggs” first appeared more than 40 million years old.

The results, published in the internationally renowned journal Current Biology on November 28, attracted a lot of attention. According to reports, the results for the discovery of embryo fossils found in the Guizhou Yan’an biota , “cage spine ball”, is the oldest animal-related embryo fossils ever discovered by humans, for the mystery of animal origin to provide an important new clue.

Rocks containing fossils

Yin Zongjun, an associate researcher at the Nanjing Institute of Geology and Paleontology of the Chinese Academy of Sciences, who participated in the whole process of collection and research, told reporters that existing studies have shown that all animals on Earth have a common ancestor, which appeared about 600 million to 700 million years ago. But such a common ancestor evolved from a single-celled life. From single-cell ancestors to multicellular ancestors, there are some transition allots, and embryonic fossils are “cage spineballs” of which are one of the transition phases.

Yin Zongjun (right) and British scientists conduct scientific examinations in the ancient biome in Yan’an

Yin Zongjun explained that the discovery of the embryonic fossil “cage spine ball” as a whole spherical, a single diameter of less than 1 mm, preserved a beautiful multicellular structure. The results showthat that these “cage spine balls” develop in a thick-walled bag filled with nutrients, and the development process is similar to the single-cell close relatives of animals, but also more complex, showing the development mechanism of animal embryos such as regular cell migration and recombination. This means that the “cage ridge ball” fossil documents a critical step in the evolution of animals from single to multicellular. It is this step that provides a biological basis for the emergence of truly cell and tissue differentiation animals.

Cage spine ball fossils, a and b are bare specimens, the bag bag has been lost, c and d are preserved in the bag specimen, e and f are a and b local amplification, showing the details of cell structure

Yin Zongjun, for example, if the first animal appears on earth is likened to “chicken”, then “egg” has a complex embryo development mechanism, this study revealed that this “egg” as early as 610 million years ago, than the “chicken” – the large number of animals appeared more than 40 million years ago.

Has been neglected for a long time

A group photo of the scientific research team in the ancient biome of Yan’an

Yin Zongjun added to reporters that in fact, as early as 2000, scientists have discovered the existence of such fossils, and named “cage spine ball.” But the fossils were poorly preserved at the time, and there were too many biological structures to be seen, so that they were neglected for a long time. Instead, the fossils collected in 2007, which were looked at through an electron scanning microscope, found that they were well preserved, even with clear cell structures, and complete bags, and so on. And that’s the fossil sample that caused a stir 12 years later.

Three-dimensional reconstruction model of caged spine fossils with internal cut-outs showing multicellular structure

“Why did the fossils be discovered in 2007, and guess edify that it might be significant, but it hasn’t been studied for a long time, and it’s not until today?” In fact, the main technology has not been breakthrough. Yin Zongjun explained that because the diameter is only 0.4-0.8 mm, and is made up of many very small cells, these cells are smaller, the general imaging technology is difficult to see clearly, before using electronic scanning mirrors, but can only look at the surface, can not see the internal structure.

Scanning electron mirror image of caged spine fossil

Yin Zongjun said that to understand what kind of organisms the fossil belongs to, what is the significance of evolutionary biology, this needs to be studied in three-dimensional structure, how the creature developed, how early embryos grow step by step. This requires 3D imaging technology to reconstruct the three-dimensional structure of hundreds of caged ridge ball specimens. But at that time, although there were some 3D imaging techniques, the resolution was not enough to be so fine. It wasn’t until 2015 that this imaging technology made a breakthrough in resolution, so it was time to scan and analyze the fossils on a large scale.

The life cycle of caged ridge balls

Yin Said said the study was conducted at the Paul Hill Institute, Switzerland’s largest research unit, where a large synchrotron radiation device, swiss light sources, was used by researchers to use x-rays of synchrotron radiation, just as doctors in hospitals gave patients CT.

“We took CT on 233 fossils and got 2.5T data. After that, the team spent two years analyzing and processing, and this year it was only this year that the paper was published. Yin Zongjun said.

Extended reading

The 82-year-old Professor of Guizhou was involved in the collection of fossils

Zhao Yuanlong, an 82-year-old paleontologist and professor at Guizhou University’s Guizhou Paleontology Research Center, is not only familiar with paleontological research, but also has a lot to do with the achievements of the ancient biota.

Zhao Yuanlong told reporters that in fact, as early as 1997, the study of Chengjiang paleontological fossil group of scientists Chen Duyuan invited Taiwan paleontologist Li Jiawei to Guizhou to search for Chengjiang paleontological fossil group of “old ancestors.” In this way, we all from Guiyang, to the Yan’an biota, and in the phosphorus ore in the middle of the phosphorus rock samples.

After that, Li returned to Taiwan to conduct research and discover embryonic fossils, and finally published research in the journal Science in the name of him and Chen, saying that the earliest fossils of animals around the world had been found, causing a sensation. Zhao Yuanlong said that since then, scientists from the United States and the United Kingdom have also cooperated in their research and achieved many results, such as Yin Zongjun’s discovery of the “Guizhou First Cup Sponge” of the sponge 600 million years ago.

Zhao Yuanlong said, interestingly, not long ago on November 10, he, Li Jiawei, Chen Duyuan three discoverers, by participating in the Cambrian outbreak in Chengjiang, Yunnan, the opportunity to participate in the Cambrian outbreak, but also specially went to the original fossil discovery of the ancient biota of Yan’an, together happy to recall the situation of collecting samples at that time, and take a photo. But at that time, he had not yet thought, more than half a month later, there was such a great result.

“This outcome is important because it involves the origin of life and is at the forefront of the world. Zhao Yuanlong said.

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