Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. A transgene is a gene or genetic material that has been transferred naturally or by any of a number of genetic engineering techniques from one organism to another. In its most precise usage, the term transgene describes a segment of DNA containing a gene sequence that has been isolated from one organism and is introduced into a different organism. This non-native segment of DNA may retain the ability to produce RNA or protein in the transgenic organism, or it may alter the normal function of the transgenic organism''s genetic code. In general, the DNA is incorporated into the organism''s germ line. For example, in higher vertebrates this can be accomplished by injecting the foreign DNA into the nucleus of a fertilized ovum.