Every ecosystem has purposeful members. A technological species is potentially genocidal. From pollutants to war to famine to ecological disaster, the technological species reshapes and rapes the planet to satisfy it's technological needs. The only purpose a technological species can fulfill on a planetary scale is the efficient manner in which they move material off planet and transplant to another planet. A technological species takes matter out of the gravity well and onto another planetary or sattelite body with minimum energy usage and wastage.
Humanity serves as a carrier for the Earth's purposes.
Not humanities own. The dominating aspect of DNA is the bases or sugars used to encode and error check the information carried by the DNA molecule. These sugars are Adenine, Thymine, Guanine and Cytosine. This is Earths Genotype. Genes carry a mechanism with which to self regulate and self perpetuate.