Student Assessment:

Dihybrid Cross Quiz

Lecture:

Recap!

-We have learned about Mendelian traits which are either dominant or recessive

-We learned about sex-linked genes

-We learned about incomplete dominant traits

Now for Co-dominant traits

-A Co-dominant trait is the opposite of an incomplete dominant trait

-With an incomplete dominant trait the two alleles blend together

-With a co-dominant trait both alleles are expressed without any blending

Here is an example of a co-dominant trait that is also sex-linked

All Calico cats are females (Well, there is a chance of having a boy calico cat. Can you guess how?)

Now lets talk about human blood type another good example of a co-dominant trait

For human blood type there are three different alleles

A

B

O

Both A and B alleles are co-dominant and O is recessive

-What does this mean?

If you get...

Genotype

AA= Type A blood

AO= Type A blood

AB= Type AB blood

BB= Type B blood

BO= Type B blood

OO= Type O blood

Blood type means what type of recognition protein is made by your blood cells

-A blood makes A proteins

-B blood makes B protein

-AB blood makes both A and B proteins

-O does not make any proteins

Student Practice:

Lets practice!