MCDOWELL COUNTY, S.C. (WSPA) - A woman was arrested on accusations that she was in an incestuous relationship with her biological uncle, according to the McDowell County Sheriff's Office. 34-year-old Tiffany Adonnus Sydnor of Marion was charged with felony incest. Her uncle, 49-year-old Corey Terrell Tate, was also charged with felony incest. Deputies said…