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, used to track traits in families.

Front

What does it mean if a trait is dominant?

Back

A dominant trait is one that is expressed in the phenotype even when only one copy of the allele is present.

Front

What does it mean if a trait is recessive?

Back

A recessive trait is one that is only expressed in the phenotype when two copies of the allele are present.

Front

What is the genotype for an individual with Huntington's Disease?

Back

The genotype can be either HH or Hh, as Huntington's Disease is a dominant trait.

Front

What is the genotype for an individual with an autosomal recessive disorder?

Back

The genotype must be hh, as both alleles must be recessive for the disorder to be expressed.

Front

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

Back

You can determine the genotype by analyzing the phenotypes of the individual and their relatives.

Front

What is the significance of the 'H' in genotypes like HH, Hh, and hh?

Back

The 'H' represents the allele for Huntington's Disease; uppercase indicates dominant and lowercase indicates recessive.

Front

What is the relationship between individuals III-2 and II-4 if one is an uncle and the other is a niece?

Back

Individual III-2 is the child of II-3, who is a sibling of II-4.

Front

What does it mean if a pedigree shows a trait skipping generations?

Back

It may indicate that the trait is recessive, as it can be carried by individuals who do not express it.

Front

What is the purpose of using pedigrees in genetics?

Back

Pedigrees are used to track traits in families and make determinations about the inheritance of genetic disorders.