Capacity to pass on their remarkable skill (12)
I believe the answer is:
Here is my best explanation:
'capacity to pass on' is the definition.
(heritability is the ability to be inherited)
'their remarkable skill' is the wordplay.
'remarkable' indicates anagramming the letters.
'skill' becomes 'ability' (I've seen this before).
'their' anagrammed gives 'herit'.