Pedigrees

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, often used to track inheritance patterns.

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What does a shaded symbol represent in a pedigree?

Back

A shaded symbol in a pedigree represents an affected individual who has the trait or disorder being studied.

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What does a circle represent in a pedigree?

Back

A circle represents a female in a pedigree.

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What does a square represent in a pedigree?

Back

A square represents a male in a pedigree.

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What is a carrier in genetics?

Back

A carrier is an individual who has one copy of a recessive allele that causes a genetic disorder but does not exhibit symptoms of the disorder.

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How can you identify carriers in a pedigree?

Back

Carriers can often be identified in a pedigree by looking for individuals who are not affected (not shaded) but have affected offspring.

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What does it mean if a trait skips a generation in a pedigree?

Back

If a trait skips a generation, it may indicate that the trait is recessive, meaning that it can be carried by individuals who do not express it.

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What is the significance of the first generation in a pedigree?

Back

The first generation in a pedigree typically represents the original individuals from whom the trait is being studied, often referred to as the 'proband'.

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How do you determine the number of generations in a pedigree?

Back

The number of generations in a pedigree is determined by counting the horizontal rows of symbols from the top (oldest generation) to the bottom (youngest generation).

Front

What does it mean if a female is represented by a half-shaded circle in a pedigree?

Back

A half-shaded circle indicates that the female is a carrier of the trait, meaning she has one affected allele but does not express the trait.