Alleles and Genes

Front

What is an allele?

Back

An allele is a variant form of a gene that can produce different traits.

Front

What is a gene?

Back

A gene is a segment of DNA that contains the instructions for building a specific protein or trait.

Front

What does homozygous mean?

Back

Homozygous means having two identical alleles for a particular gene (e.g., AA or aa).

Front

What does heterozygous mean?

Back

Heterozygous means having two different alleles for a particular gene (e.g., Aa).

Front

What is a dominant allele?

Back

A dominant allele is an allele that expresses its trait even when only one copy is present.

Front

What is a recessive allele?

Back

A recessive allele is an allele that only expresses its trait when two copies are present.

Front

What does the notation 'AA' represent?

Back

'AA' represents a homozygous dominant genotype.

Front

What does the notation 'aa' represent?

Back

'aa' represents a homozygous recessive genotype.

Front

What does the notation 'Aa' represent?

Back

'Aa' represents a heterozygous genotype.

Front

When do recessive traits show up?

Back

Recessive traits show up only when there are two recessive alleles present.