Go around ridge altering line of descent (8)
I believe the answer is:
pedigree
'line of descent' is the definition.
(synonyms)
'go around ridge altering' is the wordplay.
'go' becomes 'pee' (both can mean to urinate).
'around' means one lot of letters goes inside another.
'altering' is an anagram indicator.
'ridge' anagrammed gives 'edigr'.
'pee' going around 'edigr' is 'PEDIGREE'.
(Other definitions for pedigree that I've seen before include "List of ancestors" , "Line of ancestry, particularly a distinguished one" , "Breeding; descent" , "Ancestral line" , "High-class" .)