Position adopted by remotest ancestors (6)
I believe the answer is:
stance
'position' is the definition.
(stance is a kind of position)
'adopted by remotest ancestors' is the wordplay.
'adopted by' indicates the answer is hidden within the clue.
'STANCE' is hidden in the letters of 'remotest ancestors'.
(Other definitions for stance that I've seen before include "Posture; viewpoint" , "Pose, for a golfer say" , "Attitude or way of standing" , "Position, viewpoint" , "Standpoint" .)