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9.6: Using Pedigrees

  • Page ID
    133683
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    Pedigrees can be used to trace patterns of inheritance by looking at several generations of a family. They can be used to trace genetic diseases while giving family history and helping provide insight for future generations.

    Many conditions are genetic but the pattern of inheritance may be different depending on which chromosome the gene is found on and whether or not the mutated allele is dominant or recessive. When a mutated allele is found on the autosomes, the condition affects males and females equally. But when the mutated allele is found on a sex chromosome (X or Y), then the condition tends to predominantly affect one sex (usually male).

    clipboard_eb86f8becc7d3e80553f4f445ae39c211.png

    "Pedigrees Explained" by Karen Marks, Reedley College is licensed under CC BY 4.0

    In the example pedigree seen above, we see that there are several affected individuals, as noted by the colored-in shapes. By analyzing the relationships and connections of affected individuals, we can determine if the pattern of inheritance is autosomal dominant, autosomal recessive, sex-linked dominant, or sex-linked recessive. In this particular example, the pattern of inheritance is autosomal recessive since males and females are equally affected and the affected male on the left has two healthy parents (the “skipped generation”.)

    Now it’s your turn to practice determining patterns of inheritance using pedigrees.

    clipboard_ece15fdfe72855acc3d05b05d7cd7216a.png

    Is this autosomal or sexlinked?

    Is this dominant or recessive?

    clipboard_ece52643d971e742f494ed12d5ddb62fe.png

    Is this autosomal or sex-linked?

    Is this dominant or recessive?

    clipboard_e9f6f6a59d787ead7a9b318fa170d47ac.png

    Is this autosomal or sex-linked?

    Is this dominant or recessive?


    This page titled 9.6: Using Pedigrees is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Karen Marks and Valeria Hochman Adler.

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