Handout03HumanPedigrees

Handout03HumanPedigrees - Autosomal dominant 1. Affected...

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BIS101-001/Engebrecht Spring 2010 Handout03Human Pedigrees Autosomal Recessive 1. Affected children often from unaffected parents. 2. On average 1/4 of children are affected in mating of 2 heterozygotes. 3. Equal numbers of affected males and females. 4. Depending how rare the affected allele is, matings of affected individuals to unrelated, unaffected individuals usually produce normal offspring. Conversely, consanguineous (related individuals) marriages have a much higher chance to produce affected offspring. e.g. Cystic fibrosis (1/25 het in pop), PKU X-linked recessive 1. Many more males than females affected. 2. None of the offspring of an affected male are affected. 3. None of the sons of an affected male are affected or will pass on the disease allele. e.g., Red-green colorblindness, hemophilia
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Unformatted text preview: Autosomal dominant 1. Affected children have at least one affected parent. 2. Usually 1/2 children are affected. Most dominant disease traits are rare so most affected individuals are heterozygotes. 3. Equal numbers of affected males and females. 4. Except for the very rare case of a new mutation, unaffected parents do not produce affected children (or the disease is not fully penetrant). e.g., Huntington corea, polydactyly, brachydactyly X-linked dominant 1. Affected males have daughters that are all affected. 2. Affected heterozygous females pass the disease to 1/2 sons and 1/2 daughters. Most dominant disease traits are rare so that most affected individuals are heterozygotes. e.g. Hypophosphatemia...
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