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Sex-Linked Inheritance exam Flashcards

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Sex-Linked Inheritance exam
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  • Sex-linked inheritance


    Inheritance of genes located on sex chromosomes, primarily the X chromosome.

  • X-linked genes


    Genes found on the X chromosome.

  • Y-linked genes


    Genes found on the Y chromosome.

  • Why do X-linked recessive disorders predominantly affect males?


    Males have only one X chromosome, so a single recessive allele on the X chromosome will express the disorder.

  • Hemophilia


    An X-linked recessive disorder characterized by abnormal blood clotting.

  • What is the probability of having a male or female offspring?


    50% chance of having a male and 50% chance of having a female.

  • What is the significance of the X chromosome being larger than the Y chromosome?


    The X chromosome contains more genes (around 1100) compared to the Y chromosome (around 100).

  • What is required for a female to express an X-linked recessive disorder?


    The female must be homozygous recessive, having two recessive alleles.

  • Carrier


    An individual who has one copy of a recessive allele that causes a genetic disorder in the homozygous condition.

  • Why can't males be carriers of X-linked recessive disorders?


    Males have only one X chromosome, so they either express the disorder or do not have the allele.

  • Red-green color blindness


    An X-linked recessive disorder affecting the ability to distinguish between red and green colors.

  • What is the inheritance pattern for X-linked recessive disorders in pedigrees?


    More males are affected than females, and affected females must have an affected father and a carrier or affected mother.

  • What determines the sex of an organism?


    The presence of sex chromosomes: XX for females and XY for males.

  • X-linked dominant


    A mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

  • What is the result of crossing a homozygous red-eyed female fruit fly with a white-eyed male?


    All offspring will have red eyes.

  • What is the result of crossing a heterozygous red-eyed female fruit fly with a white-eyed male?


    50% of the females and 50% of the males will have white eyes.

  • What is the result of crossing a heterozygous red-eyed female fruit fly with a red-eyed male?


    0% of the females and 50% of the males will have white eyes.

  • What is the result of crossing a homozygous white-eyed female fruit fly with a red-eyed male?


    All males will have white eyes, and all females will have red eyes.

  • What is the likelihood of a son being affected if the mother is a carrier of an X-linked recessive disorder?


    50% chance of being affected.

  • What is the likelihood of a daughter being affected if the mother is a carrier and the father is unaffected?


    0% chance of being affected, but 50% chance of being a carrier.

  • What is the likelihood of a daughter being affected if both parents are carriers of an X-linked recessive disorder?


    25% chance of being affected.

  • What is the likelihood of a son being affected if the mother is affected by an X-linked recessive disorder?


    100% chance of being affected.