1. Human Blood Groups

2. Blood is determined by multiple alleles
3 or more alleles of the same gene that code for a single trait.
Codominant

3. There are 4 different possible phenotypes for human blood:
1. Blood Type A - I A I A or I A i 2. Blood Type B - I B I B or I B i 3. Blood Type AB - I A I B 4. Blood Type O - ii
What type is homozygous recessive?

4. Determined by the presence or absence of the antigens A and B
An antigen is a molecule that the body recognizes as foreign
Surface markers

5. b. “A” type blood had an “A” antigen, “B” blood had “B” antigen, “AB” blood had BOTH “A and B” antigen, and “O” blood has NO antigens.
c. "O" is the universal blood type donor because it contains no antigens but can only receive blood from an "O" type person. AB type blood can be received from any type of blood donor.

8. IV. Also there are Rh blood groups:
. Determined by the presence or absence of the Rh antigen.
For example Rh+ / Rh+, Rh+/Rh-, or Rh-/Rh-