Hereditary information overturning quote (7)
I believe the answer is:
genetic
'hereditary' is the definition.
(I know that hereditary can be written as genetic)
'information overturning quote' is the wordplay.
'information' becomes 'gen' (gen can informally mean information).
'overturning' says the letters should be written in reverse.
'quote' becomes 'cite' (synonyms).
'cite' back-to-front is 'etic'.
'gen'+'etic'='GENETIC'
(Other definitions for genetic that I've seen before include "- - code (biol.)" , "Relating to heredity" , "relating to origin" , "coming from a common source" , "Pertaining to heredity" .)