Basic building blocks found in Spain, Luxembourg and El Salvador, after all (7)
I believe the answer is:
alleles
'basic building blocks' is the definition.
Although both the answer and definition are plural nouns, I don't understand how one could define the other.
'spain luxembourg and el salvador after all' is the wordplay.
'spain' becomes 'e' (abbreviation for Espana).
'luxembourg' becomes 'L' (international vehicle registration code).
'and' says to put letters next to each other.
'el salvador' becomes 'ES'.
'after' is a charade indicator (letters next to each other).
'l'+'es' is 'les'.
'e'+'les'='eles'
'eles' put after 'all' is 'ALLELES'.
'found in' is the link.
Can you help me to learn more?
(Another definition for alleles that I've seen is " genes".)