It contributes to making you a bit degenerate (4)
I believe the answer is:
gene
'it contributes to' is the definition.
The definition suggests a singular noun which matches the answer.
'a bit degenerate' is the wordplay.
'a bit' indicates the answer is hidden within the clue (the answer is formed by a bit of the clue).
'GENE' is hidden in the letters of 'degenerate'.
'making you' acts as a link.
Can you help me to learn more?
(Other definitions for gene that I've seen before include "A segment of DNA" , "affects someone's make-up" , "Basic unit of heredity" , "Hereditary molecule" , "Biological factor determining heredity" .)