Final answer:
Gene transfer is the replacement of one or more genes present in the chromosome of one cell with those from the chromosome of a genetically distinct cell. It can occur naturally or through artificial methods such as gene therapy.
Step-by-step explanation:
Gene transfer is the replacement of one or more genes present in the chromosome of one cell with those from the chromosome of a genetically distinct cell. This process can occur naturally through genetic transfer or can be artificially induced using recombinant DNA technology. For example, gene therapy is an experimental method that involves inserting normal genes into cells with mutant genes to cure genetic disorders.