Information on Pettyjohn Family

My father George Pettyjohn was born in Dekalb, Texas. His father was John Henry Pettyjohn. He had two sisters Edna and Sena Mae and they lived in Oklahoma. My father was given away when he was 3 years old. He ended up in the same home as his sister Edna in the home of Tom and Minnie Samuels. Sena Mae was kept in the home with John Henry Pettyjohn and his new wife Jessie. I am looking for information regarding my father’s ancestors. We have been told that they were Cherokee on my grandfathers side. John Henry Pettyjohn was William Pettyjohn.