Dominant and Recessive Alleles Flashcards

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What is meant by a dominant allele?

A dominant allele is a version of a gene. Its trait shows even if only one copy is present.

A recessive allele is a version of a gene. Its trait only shows when there are two copies and no dominant allele.

Only one copy is needed. The trait will also appear if there are two copies.

Two copies are needed. There must be no dominant allele present.

They will show the dominant trait. The dominant allele masks the recessive allele.

A dominant allele is shown with a capital letter, like B. A recessive allele is shown with the lower-case letter, like b.

A carrier has one dominant and one recessive allele. They do not show the recessive trait but can pass it on.

No. The dominant allele hides the recessive allele, so the recessive trait does not show.

Both parents may be carriers of the recessive allele. Their child can inherit two recessive alleles and show the recessive trait.