Additional Punnette Squares

1. Additional Punnette Squares

2. Genetic Disorders: The harmful effects produced by inherited mutations. Mutations: • *are changes in genetic material • *occurs when a gene is damaged, copied incorrectly, or a faulty protein was made

3. Examples of Genetic Disorders • Sickle Cell Anemia – autosomal recessive (red blood cells are sickle-shaped and oxygen is not carried to cells) • Cystic Fibrosis – autosomal recessive (production of thick sticky mucus – affects lung) • Huntington’s Disease – autosomal dominant (neurodegenerative disorder – nerve cells start to degenerate) • Hemophilia – sex linked recessive (rare bleeding disorder – blood does not clot properly)

4. TaySachs– autosomal recessive (destroys nerve cells in the brain and spinal cord) • Phenylketonuria (PKU)– autosomal recessive (causes intellectual and developmental disabilities because body cannot break down the amino acid - phenylalanine) • Colorblindness– sex-linked recessive (a deficiency of color vision; have difficulty in distinguishing certain colors)

5. Genetic Counseling – is a form of medical guidance that informs people about genetic problems that could affect them or their offspring • Genetic Therapy – allows scientists to correct certain recessive genetic disorders by replacing defective genes with copies of healthy ones

6. Sickle Cell Anemia • Sickle cell anemia is a recessive autosomal disease. Michael and Kia are expecting their first child. Kia is a carrier of sickle cell but Michael is not. They see a genetic counselor who tells them that the probability that their child will be a carrier of sickle cell is ___ %. The probability that the child will have sickle cell is _____ %. 50 S S 0 S s SS SS Ss Ss

7. Huntington’s is a dominant disorder. • Joe and his wife Betsy are both heterozygous for Huntington’s. Their children have a ___ % chance of having Huntington’s and a ___ % chance of being normal. The probability that their child will be a carrier of Huntington’s is _____ %. 75 25 H h 0 H h HH Hh Hh hh

8. Tay Sachs is autosomal recessive. • Janet and Lee are both heterozygous for Tay Sachs disease. What are the odds that their first child will be a carrier of Tay Sachs? ______% What are the chances the child will have Tay Sachs? _____ % What are the odds that their child will be normal? ____% 50 25 75 T t TT T t Tt tt Tt

9. Colorblindness is x - linked recessive. • Jim’s father is color blind and his mother has the gene for color-blindness but has normal color vision. What are the odds that Jim is color blind? ___ % How about his sister, Sarah? What are her chances of being color blind? ___ % What are her chances of being a carrier of color-blindness?___ % 50 50 50 Xc Y Xc X XcXc XcY XY XcX

10. Phenylketonuria (PKU) is autosomal recessive. • Jane has PKU. Her husband, Darryl, neither has the gene or is a carrier. What are the chances that their children will have PKU? ____ % Not have PKU? _____% Be a carrier of PKU? ___ % 100 0 100 p p Pp P P Pp Pp Pp

11. Blood Types and Multiple Alleles • Blood type inheritance is somewhat complicated, with three forms of the gene and 4 possible phenotypes. Suppose that a man with heterozygous blood type B marries a woman with heterozygous blood type A. What are the possible blood types of their children? ___________________ AB, B, O A, A O B O AB BO OO AO

12. Cystic Fibrosisis an autosomal recessive disease. • Suppose that a man with a family history of CF marries a woman with no history of the disease. The woman has no genes for CF while the man is a carrier (heterozygous) and does not have the disease. If these people become parents, what are the chances that their children will have CF? 0% C c C C CC Cc Cc CC