Multiple Alleles and Blood Types

Multiple Alleles

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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.

Multiple Choice

Blood type is determined by the proteins on the surface of blood cells.

• true

• false

Multiple Select

Which of the following are possible human blood types? (check all that apply)

• A

• B

• C

• O

• P

Multiple Choice

A person's blood type indicates the type of _______ on the surface of their blood cells.

• antiseptic

• antibiotic

• antigen

Multiple Choice

People with blood type A have no antigens on the surface of their blood cells.

• true

• false

Multiple Choice

Blood transfusions require that the person get blood from a donor with antigens that are

• the same

• different

• the same or different; doesn't matter

Multiple Choice

The blood type that is the universal donor because anyone can receive it is

• A

• B

• O

Multiple Select

Which blood type(s) can receive blood from anyone?

• A

• B

• AB

• O

Multiple Choice

How did the Ameba sisters know that baby Phil couldn't possibly be the baby of two parents with blood type A?

• Type A is dominant over blood type B

• Baby Phil has blood type A and the parents must have a different blood type

• Both parents had blood type A; neither could have given Baby Phil the B allele

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

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