|For information relating to the term gene in Star Trek canon, see gene.|
A gene was a unit with DNA on a chromosome which contained information inherited from a parent, which, in turn, determined some of the characteristics of a lifeform. Something describing the gene was called genetic.
Genetic engineering could alter a lifeform's genetic structure. The M'Tar utilized genetic engineering in creating Liaisons and Links, types of treaties in The Great War, which they also called Treaties. They also used genetic engineering to create entire armies as in the case of the Myhr'an clones. (Star Trek: The Prospect Chronicles; Star Trek: The Cantabrian Expeditions)