Hemophilia Inheritance
The top row represents a mother who is a carrier. She has the hemophilia gene on one of her "X" chromosomes. The row on the side represents the father. He has the hemophilia gene on his "X" chromosome and is affected by hemophilia. This Punnett Square shows that the son (XY) has a 50% chance of being affected by hemophilia. A male only needs the hemophilia gene from the mother in order to have hemophilia, as opposed to a female who needs the hemophilia gene from both the mother and father. In order for the baby to be a boy, the father has to pass down a "Y" chromosome, which does not carry the disease. The mother can then pass down one of her two "X" chromosomes, one being normal and the other having the hemophilia gene on it. So, that is a 1 in 2 chance of the baby boy having hemophilia.
The pedigree shows the family history of hemophilia. The paternal grandmother was a carrier of hemophilia and the grandfather was affected by hemophilia. He died at the age of 35. They had Grover Jackson, the client, who is affected by hemophilia. Grover married Mary Neille, the other client, whose mother was a carrier of hemophilia and father was not affected by it. Mary Jackson is a carrier of hemophilia. Her sister Alicia is healthy and unaffected by hemophilia and her brothers Jeremy and Sal are unaffected by hemophilia. Looking at Grover and Mary Jackson's children we can already see that they're oldest and youngest daughters, Lisa and Nicole, are both hemophilia carriers. They're middle daughter, Amber, is affected by hemophilia. The baby, which we know will be a boy, has a 50% chance of being a hemophiliac.
Works Cited for this page ("Inheritance")
Genetics of Pregnancy Encyclopedia Corporation. X-linked dominant, affected mother. Genetics of Pregnancy Encyclopedia, 2011. JPEG.
National Heart, Lung, and Blood Institute. Inheritance Pattern for Hemophilia- Example 2. NHLBI, 2013. GIF.
National Heart, Lung, and Blood Institute. Inheritance Pattern for Hemophilia- Example 2. NHLBI, 2013. GIF.