Gene mutations can be caused by three ways: physical, chemical, and biological factors. Usually genes have strong stability and are not easy to produce changes, but genes can undergo gene mutations under the action of certain degree of internal and external environmental factors. I. Physical factors: 1. Ultraviolet light: Ultraviolet light exposure can cause damage to genetic material, abnormal changes in thymine, and affect the structure of the DNA chain, which can cause gene mutation by base pairing errors when DNA replication occurs. Therefore, prolonged exposure to sunlight can easily cause gene mutation; 2. Ionizing radiation: such as X-rays, α-rays, β-rays, γ-rays, etc. Ionizing radiation can penetrate genetic material and cause DNA fracture damage, which can easily cause gene mutation. However, a certain dose of radiation is needed to cause gene mutation. Second, chemical factors: such as hydroxylamine and nitrite chemicals can replace normal base pairs with wrong bases, which may produce errors in the replication process and lead to gene mutation. Base analogues may also be adulterated in the DNA molecule to replace the normal bases, causing pairing errors and causing gene mutations. In addition, aromatic compounds can cause the loss or misplacement of bases, and alkylating agents such as formaldehyde and vinyl chloride can mutate genes and cause gene errors, etc., which may definitely cause gene mutations. Third, biological factors: some viruses such as influenza virus, herpes virus, bacteria, etc., while replicating viral genetic material, can damage the normal replication of human DNA and mutate the human body to genetic mutation.