DNA

DNA was the substance that carried all the information about a life form's appearance, shape, form, and function. For instance, DNA in Togruta determined such things as what color the lekku were. Cloning, the process of making an identical copy of a given organism, required manipulation of said organism's DNA.

DNA could be used to establish parentage by testing a sample of a suspected parent's DNA in comparison with the individual believed to be the child. In considering whether to confirm or deny before the Galactic Senate of the New Republic that Darth Vader was her father, Leia Organa noted to herself that to her knowledge no DNA samples had ever been found labeled either "Darth Vader" or "Anakin Skywalker."