Chapter 15 Data eight

At the end of the 20th century, transgenic engineering achieved rapid development.Scientists have been able to easily implant a certain gene into other animals, plants or bacteria to achieve the purpose of industrial production. For example, the precious coagulation factor VIII in medicine needs 120 grams a year in the United States, which needs to be donated by 6 million people. Extracted from 1.2 million liters of plasma.However, if the gene of coagulation factor VIII is implanted into the mammary gland gene of dairy cows, the milk of only 1 to 2 transgenic cows can produce the above-mentioned coagulation factor.

There are roughly three ways to produce transgenes: microinjection, retroviral infection of embryos, and embryonic stem cell-mediated. Microinjection is to inject the target gene into the nucleus of sperm cells with a micro-injector just before the fertilized eggs are combined into fertilized eggs.The success rate of this method is 3‰. The retrovirus method is to use a retrovirus to infect early embryos.The so-called reverse transcription refers to the construction of deoxyribonucleic acid (DNA) using ribonucleic acid (RNA) as a model.As early as 1976, scientists infected early mouse embryos with murine leukemia virus, allowing them to integrate foreign genes and inherit them.

Embryonic stem cells are cells that have not yet specialized in function. They can develop into any animal organ, can be cultured in vitro, and proliferate from generation to generation.Scientists use retroviruses to infect stem cells, so that stem cells integrate foreign genes, and then implanted into the blastocoel of animals, they can participate in the formation of various tissues.Using this method to create transgenic mice has almost 100% success rate.