Multiple Alleles and Codominance with Blood Types

Codominance and Multiple Alleles in Blood Types

Your blood cells have little ID badges on their surface called antigens.

• Type A blood has A antigens.

• Type B blood has B antigens.

• Type AB blood has both A and B antigens.

• Type O blood has no antigens.

Match

Match the following

• Type A

• Type B

• Type AB

• Type O

A antigens

B antigens

A and B antigens

no antigens

• A antigens

• B antigens

• A and B antigens

• no antigens

Multiple Choice

What are antigens?

• Small proteins on the outside of red blood cells that act like ID cards

• Proteins in the blood that recognize each other

• Antiheros

• Pathogens

Your blood also has antibodies floating around, looking for stuff that shouldn't be there like pathogens.

In this example, the blood cells have B antigens. So the antibodies are designed to attack A antigens.

The A and B alleles are codomniant with each other, and both are dominant to the O allele.


Notice that there are two ways to write the genotypes! You can pick either, juts be consistent.

Multiple Choice

Which two alleles are codomiant?

• Type A and Type B alleles

• Type A and Type O alleles

• Type B and Type O alleles

Multiple Choice

Which allele is recessive?

• Type A allele

• Type B allele

• Type O allele

Multiple Choice

Why is blood type an example of a trait with multiple alleles?

• There are three alleles involved.

• the A and B alleles are codominant.

• There are clear dominant and recessive relationships.

• There is more than one chromosome involved.

Match

Match the following blood types to their genotypes!

• Type A

• Type B

• Type AB

• Type O

AA

BO

AB

OO

• AA

• BO

• AB

• OO

Match

Match the following blood types to their genotypes!

• Type A

• Type B

• Type AB

• Type O

I^Ai

I^BI^B

I^AI^B

ii

• I^Ai

• I^BI^B

• I^AI^B

• ii

​Check out this example! When a type AB parent and heterozygous Type A parent are crossed, some of the offspring are homozygous A, AB, heterozygous A, or heterozygous B!

Multiple Select

What are the phenotypes of the PARENTS in this cross? Choose 2 answers!

• Type A

• Type B

• Type AB

• Type O

Multiple Select

What are the phenotypes of the offspring in this cross? Choose all answers that apply!

• 50% type A

• 25% Type AB

• 25% Type B

• 50% Type O

• 75% Type A

Multiple Choice

What will be the phenotypes of the offspring in this cross?

• 50% type A, 50% type B

• 50% type O, 50% type B

• 50% type A, 50% type O

• 50% type AB, 50% type O

Multiple Select

Which of the following describe the phenotypes of the children? Check off all correct answers!

• 25% Type A

• 50% Type AB

• 25% Type B

• 50% Type O

• 75% Type A

Use the video on the next slide to help you complete it!

Make sure you holepunch this handout and put it in your binder!

​

Get a handout from the counter!