Arabian spirit losing one part of inheritance? (4)
I believe the answer is:
gene
'inheritance?' is the definition.
(I've seen this in another clue)
'arabian spirit losing one' is the wordplay.
'arabian spirit' becomes 'genie' (I've seen this before).
'losing' is a deletion indicator.
'one' becomes 'i' (Roman numeral).
'genie' with 'i' taken away is 'GENE'.
'part of' is the link.
(Other definitions for gene that I've seen before include "Hereditary unit on chromosome" , "Embarrassment" , "and 16 Down: Rockabilly singer" , "may be passed to child" , "What makes us different" .)