"Star Trek" producer Roddenberry (4)
I believe the answer is:
gene
'star trek producer roddenberry' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for gene that I've seen before include "Hereditary determinant" , "Element of heredity" , "What makes us different" , "The Selfish -- (Dawkins)" , "Vincent" .)