Beginnings of religion in Genesis is now beginning (6)
I believe the answer is:
origin
'beginnings' is the definition.
(thesaurus)
'of religion in genesis is now beginning' is the wordplay.
'of' becomes 'o' (**).
'beginning' says to take the initial letters.
The first letters of 'religion in genesis is now' is 'rigin'.
'o'+'rigin'='ORIGIN'
(Other definitions for origin that I've seen before include "base" , "Place or point of beginning (6)" , "Source, derivation" , "Starting point or cause" , "Where X meets Y" .)