Complex sentence: Dunham's father, Albert Millard Dunham, was an African-American businessman who owned a dry-cleaning business in Glen Ellyn, Illinois and who had traced his ancestry back to slaves from West Africa and Madagascar.
Split into simpler sentences: Dunham's father, Albert Millard Dunham, was an African-American businessman who owned a dry-cleaning business. Albert Dunham traces his ancestry back to African slaves from West Africa and Madagascar.