Genes are composed of DNA, referring to DNA segments that store genetic information with hereditary effects, including all deoxyribonucleotide sequences encoding a polypeptide chain or functional RNA, and can be categorized into structural and non-structural genes. Genes encode proteins, and all phenotypes of organisms are expressed as protein activity, i.e., almost all traits of organisms are formed by gene interactions, and are the basic genetic units that determine the traits of organisms. Gene expression is the transfer of genetic information from DNA to mRNA through transcription and then to protein through translation. A gene mutation is a change in the composition or sequence of the base pairs of a gene, which is passed on to the offspring and may cause defects and lead to disease. Human health is not only affected by genetic factors, lifestyle also plays a very critical role, it is recommended to have a regular routine and to consult a doctor if you feel unwell.