The Williams Family Narrative – use this to construct your pedigree
This is the story of Joan and James Williams. When James proposed marriage to Joan he explained to her that he was a carrier of the sickle cell gene. Joan who was, a biology teacher and knowledgeable in the area of Mendelian genetics was not worried about their future offspring because she knew she was not a carrier.
Three beautiful children were born to Joan and James. Their first born was a girl, Elena, followed by two precocious boys, Willie and Keith. Although Joan was not worried about the presence of sickle cell disease, she insisted on having all her children tested merely because her husband was a carrier. The results from the blood test indicated that Joan had given birth to three carriers.
All of the William’s children lead healthy productive lives and each one secured a spouse with the exception of Willie. Elena followed in her mother’s footsteps and became a biology teacher. She too insisted that her husband, Eric Jackson, be tested for the presence of the sickle cell gene. Fortunately, Eric’s test showed the DNA sequence for normal hemoglobin. Keith’s wife, Marsha was tested. Her results indicated she was a carrier like Keith. When Joan found out about Marsha, she advised them to talk extensively with a genetic counselor before starting a family. However Marsha’s strong belief in the family caused her to ignore her mother- in law’s advice. She simply wanted to have children, and she did, 2 boys; Cedric, Jeff and Nita their daughter. Unfortunately her oldest son was born with sickle cell disease, her middle child was a carrier, and the baby girl was normal.
Elena and Eric had decided to wait before starting a family, because they wanted to become financial secure and stable. After seven years of marriage they decided to start a family. Over the next six years they were blessed with four children. Nya, their oldest girl came into the world with normal hemoglobin, Eric Jr. and baby girl Shenita were both carriers, and the second son, Jason, was normal.
Aside from the normal rigors of raising a family, Eric and Elena had a good life. Although Eric Jr. and Shenita were the only siblings to marry, six grandchildren were born. Eric Jr. and wife Nicole had three children. Their oldest children were a set of identical twins girls, Nina and Tina, followed by younger brother Alex. Shenita and husband Marvin Jones (a carrier) had two girls and one boy; Mary, Susan, and Joseph. Four of the six Jackson grandchildren, all girls, were carriers. Two were born to Eric Jr. and Nicole, and two were born to Shenita and Marvin. None of the Jackson grandchildren were born with sickle cell disease.
Keith and Marsha’s only child to have a carrier genotype, Jeff, did marry. Cedric remained single due to poor health, and Nita swore off marriage after several bad relationships. Jeff and his wife Adrienne had four children, Angela, Keith, Joyce, and Denise. Although the parents were not expecting it to happen, their only son and their second born girl were born with sickle cell disease.
Post- pedigree questions: