I have no idea. I know nothing of my biological father so perhaps there's a strong link on his side?
My parents (mom & stepdad) didn't drink. They did have a liquor cabinet where they stored any alcohol they received as gifts. Didn't have many drinking relatives either.
Doesn't much matter to me. No one ever held a drink to my lips and forced me to drink. I'm an alcoholic, I'm in recovery & it's of no interest to me whether it's genetic predisposition or not.