By Bill Graveland THE CANADIAN PRESS CALGARY- The Indigenous roots of one of Alberta’s longest serving and best-known premiers is explored in a new book focusing on the ancestry of Peter Lougheed and his Metis grandmother. “The Premier and His Grandmother” is written by Doris Jeanne MacKinnon, an academic from Red Deer, Alta., who studies the important role Indigenous women have played in Prairies history. The reaction to her earlier book, “Metis Pioneers: Marie Rose Delorme Smith and Isabella Clark Hardisty Lougheed,” prompted MacKinnon to write about the Lougheed family. “As I delved into her history, I don’t recall knowing myself that Peter Lougheed had an Indigenous grandmother,” MacKinnon said in an interview. “As I would share the story of my earlier book, I would ask, ‘Do you know this?’…