Pedigrees
Amoeba Sisters・2 minutes read
A pedigree visually represents inherited traits like a family tree, with specific symbols denoting genders and generations, while shaded shapes track specific traits like attached earlobes. Attached earlobes are an autosomal recessive trait represented by the genotype "ee," showing how recessive alleles are expressed when dominant alleles are absent, with pedigrees also able to track sex-linked traits based on chromosome combinations.
Insights
- Pedigrees visually represent inherited traits like a family tree, using shapes to denote gender and shading to indicate specific tracked traits.
- Understanding alleles and genotypes is crucial in pedigrees; for example, attached earlobes are autosomal recessive, requiring the "ee" genotype, while free earlobes need at least one dominant allele. Sex-linked traits are also tracked, with females having two X chromosomes and males having one X and one Y chromosome.
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Recent questions
What is a pedigree?
A pedigree is a visual representation of inherited traits across generations, similar to a family tree. It shows how specific traits are passed down from parents to offspring.
How are males and females represented in a pedigree?
In a pedigree, circles represent females, and squares represent males. This visual representation helps track the inheritance of traits through different generations.
What do shaded shapes in a pedigree indicate?
Shaded shapes in a pedigree represent a specific trait being tracked. This shading helps identify individuals who possess or carry the trait being studied.
What does a lowercase "e" represent in a pedigree?
In a pedigree, a lowercase "e" represents the genotype for attached earlobes, which is an autosomal recessive trait. Individuals with the genotype "ee" will have attached earlobes.
How are dominant and recessive alleles expressed in pedigrees?
Dominant alleles express dominant traits, while recessive alleles are only expressed when dominant alleles are absent. In pedigrees, this information helps determine how traits are inherited and passed down through generations.
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Summary
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Understanding Pedigrees: Tracking Inherited Traits
- A pedigree is a visual representation of inherited traits across generations, similar to a family tree.
- In a pedigree, circles represent females, squares represent males, and roman numerals indicate generations.
- Shaded shapes in a pedigree represent a specific trait being tracked.
- The trait being tracked in the example is attached earlobes, which is autosomal recessive.
- Dominant alleles express dominant traits, while recessive alleles are only expressed when dominant alleles are absent.
- The genotype for attached earlobes is represented by lowercase "e."
- Individuals with attached earlobes must have the genotype "ee," while those with free earlobes must have at least one dominant allele.
- Pedigrees can also track sex-linked traits, with females having two X chromosomes and males having one X and one Y chromosome.
