The first humanoid species in the galaxy, who seeded many worlds with genetic code that guided evolution toward forms resembling their own.
The Progenitors are the ancient humanoid species that, billions of years ago, found themselves alone in the galaxy. Before dying out, they seeded the primordial oceans of many worlds with genetic material encoding a plan that would steer evolution toward bodies like their own. This explains why so many species, including humans, Klingons, Romulans and Cardassians, share a similar shape.
In the episode The Chase, set in 2369, Jean-Luc Picard's old archaeology teacher, Richard Galen, is killed while pursuing a puzzle hidden in DNA fragments scattered across distant planets. Picard takes up the search and is soon in a race with Cardassian, Klingon and Romulan ships, each side suspecting the code hides a weapon or power source. When the fragments are combined, they reveal a recorded message from a Progenitor explaining their legacy and expressing the hope that their descendants will recognise their shared origin.
Progenitor technology returns as the central quest of Discovery's fifth season. The species gives Star Trek an in-universe reason for its many humanoid aliens and a message of common kinship.