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

How many alleles does each person carry for a trait?

Back

Each person carries 2 alleles for a trait, one inherited from each parent.

Front

What does it mean to be a carrier of a trait?

Back

A carrier is an individual who has one copy of a recessive allele that does not manifest in their phenotype but can be passed on to offspring.

Front

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

Back

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

Front

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

Back

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

Front

What does a horizontal line connecting a male and female represent in a pedigree chart?

Back

A horizontal line connecting a male and female represents a mating or marriage.

Front

What does a vertical line leading down from a couple represent in a pedigree chart?

Back

A vertical line leading down from a couple represents their offspring.

Front

How can you determine if a trait is dominant or recessive using 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 is likely recessive.

Front

What is the significance of Roman numerals in a pedigree chart?

Back

Roman numerals are used to denote generations in a pedigree chart, with I being the first generation, II the second, and so on.

Front

How can you identify carriers in a pedigree chart?

Back

Carriers can be identified if they have offspring with the trait but do not express it themselves, indicating they possess one recessive allele.