Genetics (Pedigree)

Front

What is a pedigree?

Back

A pedigree is a diagram that shows the occurrence and appearance of phenotypes of a particular gene or organism and its ancestors.

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What does it mean if a trait is recessive?

Back

A recessive trait is one that is only expressed when an individual has two copies of the recessive allele (e.g., 'aa').

Front

What is the phenotype of an organism?

Back

The phenotype is the observable physical or biochemical characteristics of an organism, determined by both genetic makeup and environmental influences.

Front

What is the genotype of an organism?

Back

The genotype is the genetic constitution of an organism, specifically the alleles it possesses for a particular gene.

Front

How can you determine if an individual has a recessive trait on a pedigree?

Back

An individual with a recessive trait is typically represented by a shaded symbol on the pedigree.

Front

What does 'Aa' represent in genetics?

Back

'Aa' represents a heterozygous genotype, where 'A' is the dominant allele and 'a' is the recessive allele.

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What does 'aa' represent in genetics?

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'aa' represents a homozygous recessive genotype, meaning the individual expresses the recessive trait.

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What is the probability of a child having a recessive trait if both parents are heterozygous (Aa)?

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There is a 25% chance (1/4) that the child will have the recessive trait.

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What does a shaded square represent in a pedigree?

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A shaded square represents a male individual who expresses the trait being studied.

Front

What does a shaded circle represent in a pedigree?

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A shaded circle represents a female individual who expresses the trait being studied.