Pedigree Review

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What is a pedigree chart?

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A pedigree chart is a diagram that shows the occurrence and appearance of phenotypes of a particular gene or organism and its ancestors, used to analyze the inheritance of traits.

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What does it mean if a trait is recessive?

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A recessive trait is one that is expressed in an individual only when two copies of the recessive allele are present (homozygous).

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How can you determine the genotype of an individual from a pedigree?

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You can determine the genotype by analyzing the phenotypes of the individual and their relatives, considering the inheritance patterns of the traits.

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What is the significance of generation labels in a pedigree?

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Generation labels (I, II, III, etc.) indicate the different generations in a pedigree, helping to track the inheritance of traits over time.

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What does it mean if an individual is represented by a filled shape in a pedigree?

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A filled shape typically indicates that the individual expresses the trait being studied, often a recessive trait.

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What is the difference between homozygous and heterozygous genotypes?

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Homozygous means having two identical alleles for a trait (e.g., RR or rr), while heterozygous means having two different alleles (e.g., Rr).

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How do you identify carriers of a recessive trait in a pedigree?

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Carriers of a recessive trait are typically represented by individuals who do not express the trait but have affected offspring, indicating they possess one recessive allele.

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What is the purpose of using symbols in a pedigree chart?

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Symbols in a pedigree chart help to visually represent individuals, their relationships, and the presence or absence of traits, making it easier to analyze genetic inheritance.

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What does the term 'phenotype' refer to?

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Phenotype refers to the observable physical or biochemical characteristics of an organism, as determined by both genetic makeup and environmental influences.

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How can you tell how many males are in a generation from a pedigree?

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You can count the number of squares (which represent males) in the generation level of the pedigree chart.