As you are adopted, you are allowed to have two profiles. One for the family you grew up with, and one for your biological family (which then works for DNA).
https://www.wikitree.com/wiki/Help:Adoptions_and_Multiple_Parents
https://www.wikitree.com/wiki/Space:Adoptees:_How_to_Set_Up_Your_Profile
https://www.wikitree.com/wiki/Space:DNA_Basics_for_Adoptees
This question from 2014 has an answer by Eowyn showing her two profiles.