Multiple Allele Systems and Blood Groups Flashcards
What are multiple allele systems?
Genes that are controlled by more than two alleles
What are human ABO blood group antigens? What are the four human blood groups? What gene controls their expression? Which two alleles are codominant? What antigens do each produce?
Antigens- immunogenically reactive proteins
I^A- A antigen results in A surface protein
I^B -B antigen results in B surface protein
i- no surface protein
Four human blood groups- A, B, AB, O
The A and B alleles are codominant; they produce A, B and AB antigens
What is an antibody? What is agglutination? Why is it important that people receive compatible blood types during transfusions?
Antibody- a protein which is produced to attach to and elicit an immune reaction to foreign antigens
Agglutination- Blood clumping
It is important that people receive a compatible blood type b/c otherwise the recipients antibodies will initiate a response and cause agglutination, which can be deadly
Be able to identify which blood types are compatible and know why they are compatible. What is the universal donor? What is the universal recipient?
Type A- can only receive blood from types A and O
Type B- can only receive from types B and O
Type AB- can receive from any type; universal recipient
Type O- can only receive from type O, but can be donated to any type; universal donor
What is the Rh Factor? What gene controls its expression? How many alleles exist for the D gene? What two phenotypes can occur?
Rh is another blood antigen, controlled by the D gene.
The D gene only has two main alleles; therefore Rh+ and Rh- phenotypes
What is erythroblastosis fetalis? How does it occur during pregnancy? What is the treatment to prevent onset of the disease?
When an Rh- mother becomes pregnant with an Rh+ child, her body will develop anti-Rh antigens, if she has another Rh+ child, the mother’s antibodies can attack the fetus and cause sever damage
This is prevented by injecting the mother with RhoGAM, which is an antibody that blocks the mother’s detection of Rh+ blood cells
What is the H gene? What is the Bombay phenotype? What type of epistasis is demonstrated by the H gene and what is the hypostatic gene?
The H gene controls the addition of glycoproteins to red blood cells; if the genotype is hh, no glycoproteins can attach to the cells, so regardless of what blood type is determine by the I gene, if a person is hh, their blood phenotype will be O – the Bombay phenotype–
The H gene epistatic to the I gene; the I gene is hypostatic to the H gene
