Pedigree

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

What does a filled square represent in a pedigree chart?

Back

A filled square represents an affected male.

Front

What does a filled circle represent in a pedigree chart?

Back

A filled circle represents an affected female.

Front

What does an empty square represent in a pedigree chart?

Back

An empty square represents a not affected male.

Front

What does an empty circle represent in a pedigree chart?

Back

An empty circle represents a not affected female.

Front

What is the significance of horizontal lines connecting squares and circles in a pedigree?

Back

Horizontal lines represent mating between individuals.

Front

What is the significance of vertical lines in a pedigree?

Back

Vertical lines represent the offspring of the individuals connected by horizontal lines.

Front

What does it mean if a trait is autosomal recessive?

Back

An autosomal recessive trait means that an individual must inherit two copies of the recessive allele to express the trait.

Front

If individual II-3 in a pedigree has an autosomal recessive disorder, what must their genotype be?

Back

hh (homozygous recessive).

Front

How can you determine the number of affected individuals in a pedigree?

Back

Count the filled squares and circles, which represent affected males and females, respectively.