Complex sentence: Gajdusek's father was from Slovakia and his mother from Debrecen, Hungary, who emigrated to the United States and settled down in Yonkers, New York, where their son was born.
Split into simpler sentences: Gajdusek's father was from Slovakia and his mother from Debrecen, Hungary. They emigrated to the United States and settled down in Yonkers, New York, where their son was born.