"an individual resulting from the interbreeding of diverse breeds or strains; especially : one of unknown ancestry "
Mongrel sounds appropriate.
obama quote;
“When asked about his background, which includes a black father and white mother, Obama said of African-Americans: “We are sort of a mongrel people.”
http://thehill.com/homenews/administration/111611-obama-calls-african-americans-a-mongrel-people-