Zurich banker invests European cell contents (6)
I believe the answer is:
genome
'cell contents' is the definition.
The definition suggests a singular noun which matches the answer.
'zurich banker invests european' is the wordplay.
I cannot quite see how this works, but
'european' could be 'e' (abbreviation e.g. EU) and 'e' is found within the answer.
'banker' could be 'gnome' (I have seen 'international banker' mean 'gnome' so perhaps 'banker' could also mean 'gnome') and 'gnome' is located in the remaining letters.
No letters remain.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for genome that I've seen before include "blueprint for life" , "What specifies all characteristics" , "Full set of chromosomes of an individual" , "The full DNA sequence of an organism" , "Cocktail, borer" .)