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PEDIGREE CHARTS A family history of a genetic condition or trait.

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Presentation on theme: "PEDIGREE CHARTS A family history of a genetic condition or trait."— Presentation transcript:

1 PEDIGREE CHARTS A family history of a genetic condition or trait

2 W HAT IS A PEDIGREE CHART ? Pedigree charts show a record of the family of an individual. They can be used to study a hereditary condition or trait. They are especially useful when there are large families that cover several generations. © 2007 Paul Billiet ODWSODWS

3 S TUDYING HUMAN GENETICS Today genetic engineering has new tools to offer doctors studying genetic diseases A genetic counselor will still use pedigree charts to help determine the distribution of a disease in an affected family © 2007 Paul Billiet ODWSODWS

4 ORGANIZING A PEDIGREE CHART Generations are identified by Roman numerals & are on different levels. I II III IV

5 Males are represented by the square Females are represented by the circle I II III IV

6 Parents are connected with a horizontal line. Offspring are below the parents and the bracket is connected by a vertical line. Siblings are within the same bracket.

7 READING THE 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


9 Genetic Counselors use a pedigree chart to predict the probability of transmitting an inherited disorder. Cystic Fibrosis – autosomal recessive

10 Huntingtons Disease is autosomal dominant.

11 Hemophilia is a blood disorder that affects blood clotting. It comes from a recessive gene on the x-chromosome. Use the pedigree chart on worksheet to trace hemophilia through the Royal family.

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