Dorothy Johnston 87 of Abilene passed away Friday April 8 2011at home surrounded by her daughters and granddaughters. A family memorial service was held in her backyard officiated by David Cason. Her two daughters four grandchildren and their spouses and her 12 great-grandchildren were present for the service.   "Mammy" taught school for 32 years in Monahans TX Pecos TX and Midland TX. She also did volunteer work for Odessa TX.   She was preceded in death by her husband of 50 years Clay Johnston.   She is survived by two daughters: Lou Hanna of Abilene and Pat Turman and her husband Greg of Dallas; four grandchildren and their spouses: Kevin and Michelle Hanna of Abilene Heather and Buddy Long of Greer SC Brandon and Shirra Hanna of Austin TX and Heidi and Chris Jones of Greer SC; and 12 great-grandchildren: Cassidy Cameron and Cason Hanna Cal Wilson Anna Claire Lauren and Bobby Long Charlie Hanna Christopher Rosemary and Audrey Jones.    Online condolences can be made at www.northsfuneralhome.com