Of genetically different groups of people (6)
I believe the answer is:
racial
'of genetically different groups of people' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for racial that I've seen before include "Relating to different branches of humanity" , "on coloured lines?" , "Pertaining to ethnic groups" , "Of particular people or colour, as with prejudice" , "Relating to distinctive human group" .)