The central dogma (genetic central dogma) refers to the process by which genetic information is transmitted from DNA to RNA, and then from RNA to protein, that is, the transcription and translation of genetic information are completed. It can also be passed from DNA to DNA, that is, completing the DNA replication process. This is the law followed by all living things with cellular structures. The self-replication of RNA in some viruses (such as tobacco mosaic virus, etc.) and the process of reverse transcription into DNA using RNA as a template in some viruses (some oncogenic viruses) are supplements to the central dogma. The process of RNA self-replication and reverse transcription cannot occur when the virus exists alone, and can only occur after it parasitizes into host cells. Reverse transcriptase is a very important enzyme in genetic engineering. It can synthesize target genes using known mRNA as a template. It is an important means to obtain target genes in genetic engineering. The central dogma (genetic central dogma) refers to the process by which genetic information is transmitted from DNA to RNA, and then from RNA to protein, that is, the completion of the transcription and translation of genetic information. It can also be passed from DNA to DNA, that is, completing the DNA replication process. This is the law followed by all living things with cellular structures. The self-replication of RNA in some viruses (such as tobacco mosaic virus, etc.) and the process of reverse transcription into DNA using RNA as a template in some viruses (some oncogenic viruses) are supplements to the central dogma. The process of RNA self-replication and reverse transcription cannot occur when the virus exists alone, and can only occur after it parasitizes into host cells. Reverse transcriptase is a very important enzyme in genetic engineering. It can synthesize target genes using known mRNA as a template. It is an important means to obtain target genes in genetic engineering.