Conjoined gene, also known as "fusion gene," refers to a type of genetic mutation where two or more genes join together. This process can occur naturally, but it can also be caused by certain environmental factors, such as radiation and chemicals. There are several other terms used to refer to this type of mutation, including chimera gene, hybrid gene, and junctional gene. Additionally, some researchers refer to them as fusion transcripts or chimeric transcripts. The study of conjoined genes is crucial in understanding the development and progression of certain diseases, such as cancer, as well as advancing genetic engineering and gene therapy techniques.