Blood Types A O B AB Donor Recipient Genotype Phenotype Antigen Antibody Homozygous Dominant Heterozygous Recessive
“ Types” of Blood The ABO Blood Group: One factor in determining blood types is by the presence or absence of co-dominant , genetically determined (inheritable) protein molecules present in red blood cell membranes. These proteins are called agglutinogen A (antigen A) & agglutinogen B (antigen B). It is the presence of one, both, or neither that determines a person’s blood type (both phenotype and genotype ) according to the ABO group.
Thus, there are four major blood types based only on the ABO group: Plasma carries agglutinins ( antibodies ) to the agglutinogen not carried on the cell membrane. Red Blood Cells Plasma Type A Type B Type AB Type O
Remember that agglutinogen A & B are dominant traits. This means that it only takes one allele to inherit the trait. Type A, B, AB, or O are the physical expression of a person’s genes which means they are phenotypes . This means that there are multiple genotypes for type A and type B
AB Ao Bo oo A man who is heterozygous Type A marries a woman who is heterozygous Type B. What are the possible phenotypes and genotypes of their children? Remember your Punnett square problems? 4 Genotypes AB Ao Bo oo 4 Phenotypes AB A B O
Let’s try another Punnett square!!! A man who is blood type AB marries a woman who is heterozygous type B . If they had four children, what would their probable genotypes and phenotypes be? AB Bo BB Ao 4 Genotypes AB Ao BB Bo 3 Phenotypes AB (1/4) A (1/4) B (2/4) 1 Child AB or 1 Child A 2 Children B A B o B Homozygous Type B Heterozygous Type B
Percentages of each ABO type in the U.S. 45% Type O 40% Type A 11% Type B 4% Type AB
The Rh Factor Red blood cells carry proteins on their surfaces in addition to the “A” and “B” antigens. The Rhesus factor , or Rh , is a protein carried by some individuals. If a person's red blood cells carry the Rh factor, they are considered to be “Rh positive (Rh + ).” If not, they are “Rh negative (Rh - ).” Rh is a dominant trait so only one allele is needed to be Rh + .
What this means is that there really are eight (8) major blood phenotypes: Can you name them? A - , A + , O - O + , AB - , AB + , B - , B + , Let’s have some fun!!
If a heterozygous type B, heterozygous Rh + woman married a heterozygous type A, heterozygous Rh + man, what are the possible phenotypes of their children? Mom’s Genotype? Dad’s Genotype? Mom’s Phenotype? Dad’s Phenotype? Possible Combinations: B + A + Bo Rh + Rh - Ao Rh + Rh - B Rh + , B Rh - , o Rh + , o Rh - o Rh + , Possible Combinations: o Rh - A Rh - , A Rh + ,
Phenotypes 3 AB+ 3 A+ 3 B+ 3 O+ 1 AB- 1 A- 1 B- 1 O- Mom Dad B Rh + B Rh - o Rh + o Rh - A Rh + A Rh - o Rh + o Rh - AB++ AB+- Ao++ Ao+- Ao-- Ao+- AB-- AB+- oo+- oo++ Bo+- Bo++ Bo+- Bo-- oo+- oo-- AB ++ AB +- Ao ++ Ao +- Ao -- Ao +- AB -- AB +- oo +- oo ++ Bo +- Bo ++ Bo +- Bo -- oo +- oo -- ABO Phenotypes 4 AB 4 A 4 B 4 O Ratio 1:1:1:1 Rh Phenotypes 12 Rh + 4 Rh - Ratio 3:1 A Different Look:
Which blood phenotype, in theory, could receive blood from any donor? AB + Why? A person with AB + is called a Universal Recipient . They have all factors present already so the body does not perceive anything foreign.
Which blood phenotype, in theory, could donate blood to any recipient? O - Why? A person with O - is called a Universal Donor . They have no factors present so the body cannot perceive anything foreign.