This document discusses methods for transferring genes between organisms through chemical means. It describes calcium phosphate and lipid-mediated gene transfer, which are two common chemical methods. Calcium phosphate forms a precipitate that binds DNA and transfers it into cells, while lipid-mediated transfer uses liposomes to encapsulate DNA and fuse with cell membranes to deliver the DNA. Both methods can be used for transient or stable transfection but have limitations such as low efficiency. The document also provides details on the mechanisms, advantages, and applications of these chemical gene transfer methods.