Pedigree Charts

Front

What is a pedigree chart?

Back

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.

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 (homozygous dominant) or Hh (heterozygous), as it is a dominant trait.

Front

In a pedigree chart, what does a filled shape represent?

Back

A filled shape represents an individual who expresses the trait being studied.

Front

In a pedigree chart, what does an unfilled shape represent?

Back

An unfilled shape represents an individual who does not express the trait being studied.

Front

What does a horizontal line between two shapes indicate in a pedigree chart?

Back

A horizontal line indicates a marriage or mating between two individuals.

Front

What does a vertical line connecting a couple to their offspring indicate?

Back

A vertical line indicates the parent-child relationship.

Front

How can you determine if a trait is dominant or recessive from a pedigree chart?

Back

If the trait appears in every generation and is passed from parents to offspring, it is likely dominant. If it skips generations, it may be recessive.

Front

What is the significance of the number of generations in a pedigree chart?

Back

The number of generations helps to understand the inheritance pattern and the likelihood of traits being passed on.