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.

Front

How many alleles does a child inherit from each parent for a trait?

Back

1 allele from each parent, totaling 2 alleles for a trait.

Front

What is a carrier in genetics?

Back

A carrier is an individual who has one copy of a recessive allele that does not manifest the trait but can pass it on to offspring.

Front

How many alleles does a person carry for a trait?

Back

2 alleles, one inherited from each parent.

Front

What does it mean if a trait is recessive?

Back

A recessive trait only appears in an individual if both alleles are recessive (e.g., 'hh').

Front

In a pedigree, how can you identify a carrier?

Back

A carrier can be identified if they have a recessive allele but do not show the trait.

Front

What is the relationship between individuals III-2 and II-4 if III-2 is the niece of II-4?

Back

II-4 is the uncle of III-2.

Front

What genotype must an individual have to express a recessive disorder?

Back

The genotype must be 'hh' (homozygous recessive).

Front

What is the purpose of a pedigree chart?

Back

To track the inheritance of traits and genetic disorders through generations.

Front

What does it mean if an individual is homozygous for a trait?

Back

Homozygous means having two identical alleles for a particular gene (e.g., 'HH' or 'hh').