Multiple Alleles

Multiple alleles: many variations of a gene

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So far, we've looked at scenarios where there was one dominant allele and one recessive allele. In many cases, there are three, four, or more possible alleles for a trait.

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Remember that variation within a species helps to ensure survival of the species.

Example of Multiple Alleles

• Example of multiple alleles: fur color and length in cats

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• Cats can have a basic fur color of black, brown, or orange/red.

• Cats can have no hair, short hair, and there are two different alleles for long hair.

Example of Multiple Alleles in Rabbits

Rabbits can have four different types of coloring, as seen in this diagram.

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​Consider: What other domesticated animals have many different fur colors, textures, and lengths?

Multiple Alleles in Humans

All humans have one of four blood types: A, B, AB, or O.

Video Segment 1

Click on the image on the next slide to watch the first segment of the

This is a visual representation of the antigens (proteins) on blood cells.

​This illustration shows all blood types, and makes it clear why O negative is the universal donor.

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