Pedigree and Sex-Linked Traits

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What is a pedigree?

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A pedigree is a diagram that shows the genetic relationships among family members and how traits are passed down through generations.

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What does autosomal recessive mean?

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Autosomal recessive means that a trait or disorder is inherited when both copies of a gene (one from each parent) are mutated or nonfunctional.

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What is a sex-linked trait?

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A sex-linked trait is a trait that is associated with a gene located on a sex chromosome, often affecting males and females differently.

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What is colorblindness?

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Colorblindness is a condition where a person has difficulty distinguishing certain colors, often due to a sex-linked recessive gene.

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What does genotype mean?

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Genotype refers to the genetic makeup of an individual, specifically the alleles they possess for a particular gene.

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What is the difference between X^A and X^a?

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X^A represents a normal allele for a trait, while X^a represents a mutated or recessive allele for that trait.

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What does it mean if a trait is sex-linked recessive?

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It means that the trait is carried on the X chromosome and is expressed in individuals who have two copies of the recessive allele (females) or one copy (males).

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How can you tell if a trait is autosomal dominant?

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If the trait appears in every generation and affected individuals have at least one affected parent, it is likely autosomal dominant.

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What is hemophilia?

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Hemophilia is a sex-linked recessive disorder that affects the blood's ability to clot, leading to excessive bleeding.

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What does it mean if an individual has the genotype hh?

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It means that the individual has two recessive alleles for a trait, which typically results in the expression of a recessive disorder.