1. A family history of a genetic condition © 2007 Paul Billiet ODWSODWS

2. What is a pedigree chart? Pedigree charts show a record of the family of an individual They can be used to study the transmission of a hereditary condition They are particularly useful when there are large families and a good family record over several generations. © 2007 Paul Billiet ODWSODWS

3. Studying human genetics You cannot make humans of different types breed together Pedigree charts offer an ethical way of studying human genetics Today genetic engineering has new tools to offer doctors studying genetic diseases A genetic counsellor will still use pedigree charts to help determine the distribution of a disease in an affected family © 2007 Paul Billiet ODWSODWS

4. Symbols used in pedigree charts Normal male Affected male Normal female Affected female Marriage A marriage with five children, two daughters and three sons. The eldest son is affected by the condition. Eldest child  Youngest child © 2007 Paul Billiet ODWSODWS

5. Organising the pedigree chart A pedigree chart of a family showing 20 individuals © 2007 Paul Billiet ODWSODWS

6. Organising the pedigree chart Generations are identified by Roman numerals I II III IV © 2007 Paul Billiet ODWSODWS

7. Organising the pedigree chart Individuals in each generation are identified by Arabic numerals numbered from the left Therefore the affected individuals are II3, IV2 and IV3 I II III IV © 2007 Paul Billiet ODWSODWS

8. Example of a Pedigree!

9. 1. Constructing a Pedigree 2. Males represented by squares 2. Females are represented by circles 2. A marriage is a line between 2 shapes 2. Offspring are shown using a line from a marriage

10. 2. Shaded shapes show people that have a trait 2. Unshaded shapes do not show the trait 2. Sometimes a heterozygous person is half-shaded

11. Practice – Write the answers to these questions on a piece of paper. 1. In this pedigree, which numbers are females? 2. Which numbers are male? 3. How many brothers does # 11 have? 4. Who is # 9 married to? 5. How many children does couple 1 and 2 have? 6. Which are married? 7. Which show the trait for which the pedigree was constructed? 8. Guess: do you think this trait is inherited as a dominant allele or a recessive allele? WHY?

12. Practice – Write the answers to these questions on a piece of paper. Use the numbers to show which people are the answers to each question 1. In this pedigree, which numbers are females? 1,4,7,8,10,11,13,15,16,17,18,19 2. Which numbers are male? 2,3,5,6,9,12,14,20 3. How many brothers does # 11 have? 1 (#12) 4. Who is # 9 married to? 8 5. How many children does couple 1 and 2 have? 3 6. Which are married? # 4 and #6 7. Which show the trait for which the pedigree was constructed? 2,6,9,11,16,20 8. Guess: do you think this trait is inherited as a dominant allele or a recessive allele? WHY?

13. Try using a pedigree to determine genotypes….. If this pedigree follows a trait that is coded for by a recessive allele…. What is the genotype of parent 1? Parent 2? The daughter? The son? A = dominant allele a= recessive allele

14. Try using a pedigree to determine genotypes….. If this pedigree follows a trait that is coded for by a recessive allele…. What is the genotype of parent 1? Aa Parent 2? Aa The daughter? aa The son? A__ (we can’t know the second allele yet) A = dominant allele a= recessive allele

15. Figure out if the trait is dominant or recessive…… Do you think this pedigree shows a dominant trait or a recessive trait? Explain why and draw a punnett square to support your answer.

16. In this pedigree, the trait must be dominant, and the parents must both be heterozygous AAAa aa A a A a

17. Summarize…… List several types of information that pedigrees can be used for. Explain how a pedigree is constructed Explain whether the pedigree here shows a dominant trait or a recessive trait and explain why you think so using a punnett square.

18. Try making a pedigree! The gene which results in Achondroplasia is dominant. Use the numbers to make a pedigree which follows the genotypes of each person in this picture. You can use the numbers to show who is who on the pedigree. 5 1 2 3 4 6

19. Challenge! Albinism is inherited as a recessive allele. In the figure above, assuming that persons from the general population are not heterozygous for albinism (Aa), what are the genotypes of all persons whose genotypes are known?

20. Case Study Learn about a disorder called Alcaptonuria (  click here).Alcaptonuria Read the fact sheet and determine the following : What are the SYMPTOMS of alcaptonuria? What are the CAUSES of alcaptonuria? What test determines whether a patient has alcaptonuria? What are some effective treatments for alcaptonuria?

21. A.D.A.M. Medical Encyclopedia. Alkaptonuria AKU; Alcaptonuria; Homogentisic acid oxidase deficiency; Alcaptonuric ochronosis Last reviewed: May 15, 2011. Alkaptonuria is a rare condition in which a person's urine turns a dark brownish-black color when exposed to air. See also: Inborn error of metabolismInborn error of metabolism Causes, incidence, and risk factors A defect in the HGD gene causes alkaptonuria. The gene defect makes the body unable to properly break down certain amino acids (tyrosine and phenylalanine). As a result, a substance called homogentisic acid builds up in the skin and other body tissues. The acid leaves the body through the urine. The urine turns brownish- black when it mixes with air. Alkaptonuria is inherited, which means it is passed down from parents to their children. To get this disease, each of your parents must pass you a copy of the faulty HGD gene.

22. Symptoms Urine in an infant's diaper may darken and can turn almost black after several hours. However, many persons with this condition may not know they have it until mid-adulthood (around age 40), when joint and other problems occur. Symptoms may include: Arthritis (especially of the spine) that gets worse over time Darkening of the ear Dark spots on the white of the eye (sclera) and corneasclera Signs and tests A urine test (urinalysis) is done to test for alkaptonuria. If ferric chloride is added to the urine, it will turn the urine a black color in patients with this condition.urinalysis Treatment Some patients benefit from high-dose vitamin C. This has been shown to decrease the build-up of brown pigment in the cartilage and may slow the development of arthritis. Expectations (prognosis) The outcome is expected to be good.

23. Complications People with this condition also can get arthritis in adulthood. The build-up of homogentisic acid in the cartilage causes arthritis in about 50% of older adults with alkaptonuria.arthritis Homogentisic acid also can build up on the heart valves, especially the mitral valve. This can sometimes lead to the need for valve replacement. Coronary artery disease may develop earlier in people with alkaptonuria. Coronary artery disease Kidney stones and prostate stones may be more common in people with alkaptonuria. Kidney stones Calling your health care provider Call your health care provider if you notice that your own urine or your child's urine becomes dark brown or black when it is exposed to air. Prevention There is no know prevention. References Chakrapani A, Holme E. Disorders of tyrosine metabolism. In: Fernandes J, Saudubray J-m, van den Berghe G, Walter JH, eds. Inborn Metabolic Diseases: Diagnosis and Treatment. 4th ed. New York, NY: Springer;2006:chap 18.

24. The Story A new baby is born into the family!! Baby Jenna appears health and strong, but nurses notice that her diaper has turned a disturbing brown/black color. After testing, the doctor diagnoses the child with alcaptonuria. The family now needs to know more about the disease, so you are called in to help. Your goals: 1. Determine who in the family has the disease 2. Design a pedigree to help the family see how the trait has moved through the family. 3. Explain how the trait is inherited in a way that the family understands.

25. Start your research 1. Test the urine of the family.  Request urine samples of family members  Add the test solution to the tube  Record the results. 2. Design a pedigree and indicate who is affected and who is not (hint: you may benefit from designing the pedigree before the test and then shading in the affected family members later. ) 3. Fill in the genotypes of each of the family members on the pedigree.

26. The family: John and Lucy are the parents of baby Jenna John has 1 sister named Suzanne John’s parents are Steven and Martha Lucy’s parents are David and Ann Lucy has a brother, Randy and a sister Lynne, the sister showed the same symptoms.

27. Queen Victoria’s Pedigree Chart