Bit of inheritance (4)
I believe the answer is:
'bit of inheritance' 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 "___ Kelly, star of Singin' In The Rain, d. 1996" , "Something got from parent < for boy" , "The Selfish -- (Dawkins)" , "Part of DNA" , "What makes us different" .)