动物实验,基因改造 z-bo 2020-08-28 469

　　All ant colonies can work together, and all ants run around, working closely with other siblings and sisters to complete their assigned tasks. Therefore, ant colonies are sometimes referred to as "super individuals." Now, researchers have analyzed the world's first genetically modified ants and found that their sociality depends mainly on their sense of smell. This discovery provides important clues for understanding how the social behavior of insects has evolved.

　　"This is a breakthrough in the field of experimental biology," said Bert Heldbler, a behavioral biologist at Arizona State University who was not involved in the research. Before that, no one had successfully produced genetically modified ants for research.

　　Generally speaking, social insects have different social classes and division of labor. These are important models for studying behavior and social evolution. Since the Darwin era, biologists have been deeply attracted by the development of social behavior.

　　Disparate creatures such as ants and humans live in closely connected groups. Israeli researchers have observed that a group of ants are working together to "lift" the "huge" food to the "home", "lift" the ants behind, and "pull" the ants in front. The more ants that can deliver food, the faster they can go home. The direction of "coordination" is "new team members" who occasionally join the team during their journey. Every time a new ant joins the processing team, the route will be adjusted, and the "old team" will follow the instructions of the "new team". During this ongoing calibration process, the entire Ali team took the food home. In addition, honeybee research also provides clues about how genes affect this socialization, but it is very difficult to determine the function of these genes in insects such as bees and ants. Yes. Part of the reason is that researchers do not have a good way to interfere with target genes. However, although this is easy to do in mice, it does not allow us to accurately search for the gene of interest. In addition, social insects are particularly difficult to genetically modify. Laurent Keller, an evolutionary biologist at the University of Lausanne in Switzerland, said that even if scientists can modify their genes, "ant eggs are very sensitive and it is difficult to reproduce without worker ants." In addition, the life cycle of social insects is so complicated that it is difficult to obtain a large number of genetically modified offspring within a certain period of time.

　　So, Daniel Kronauer, an evolutionary biologist at Rockefeller University in New York, turned his attention to an asexual ant-asexual marching ant. Asexual marching ants belong to the Myrmidinae subfamily. You can prey on ants and attack other ants' nests. The colony’s life cycle consists of two stages. One stage is reproduction, and the other stage is predation and protection. Unlike other ant populations, this dwarf marching ant colony does not have a queen. All offspring are reproduced by omnipotent worker ants.

　　This means that researchers can modify individual ant genes to quickly develop genetically modified chains. "In the vast majority of ant populations, this situation is basically non-existent." Due to potential problems in the processing of eggs and larvae, Croner obtained a normal genetically modified strain. This takes several years, but this "shortcut" ants reproduce asexually.

　　Asexual reproduction Kronauer team's Waring Trible and Leonora Olivos-Cisneros use CRISPR technology to modify genes in ants, which makes it easier for scientists to adapt to genes. I can do it. Earlier, researchers discovered that the genotypes of marching ants in the same ant nest are very similar, and they reproduce through a method of asexual reproduction called central fusion self-fertilization. Scientists can transfer ant colonies to the laboratory for reproduction and control the size of each colony. In addition, the life cycle of the asexual marching ant colony changes simultaneously, allowing researchers to precisely control the age of the ants.

　　In a new study, Tribble disrupted a gene called orco. It can provide the protein needed to maintain the function of nerve cells whose antennae are sensitive to smell. These cells, called odorants, are one of several sensory organs that can detect pheromone. Animals (such as ants) use this chemical to communicate. Compared with 46 species in fruit flies, ants may have at least 350 more odorant receptors than other animals. Therefore, researchers suspect that the receptor is related to the complex social system of ants. As a result, genetically modified ant behavior and brain anatomy indicate that more and more odor receptors are working. Researchers recently reported bioRxiv. Young adult ants usually stay with their nest partners in the first month, while genetically modified ants roam quickly. In addition, genetically modified ants cannot detect the clues left by other ants, but finding matches and clues is an important behavior that the ant population can maintain.

　　What is more surprising is the effect of genetic modification on the brain. The nerve endings of various odor receptors are in contact with glomerular clusters. The research team removed a gene from the fruit fly killer whale, but its glomeruli were not affected. However, as far as ants are concerned, the transformed ants will not form glomeruli. This is consistent with the results produced by knocking out similar genes in the mouse brain. Geneobinson, a behavioral geneticist at the University of Illinois in the United States, said that the result was “compelling” and provided people with an opportunity to compare the brain development of different species and scientists. He said he would be able to understand the behavior behind The mechanism of brain evolution.