Blood Types

What alleles has a person who is Rh-negative inherited?

d/d

What does the i allele code for?

i codes for an inactive enzyme.

If both parents are homozygous recessive for the Rh-factor allele, what is the probability that the mother will react to her second baby's blood?

0%

What is the frequency of the h/h phenotype in Bombay?

1 in 10,000

Name the most commonly used blood typing systems.

1. MN system 2. Rh factor 3. ABO system

If the father is homozygous dominant for the Rh-factor allele, what is the probability that the Rh-negative mother will react to her second baby's blood?

100%

How many blood typing systems are there?

32

What is the frequency of the h/h phenotype per million in the human population?

4 per million of the human population

What does a non-functional H gene prevent?

A non-functional H enzyme prevents the addition of A and B carbohydrate chains, thus resulting in a masked phenotype that resembles an O blood type.

What is the universal recipient blood type?

AB+ is the universal recipient, but can only donate to like blood types because a person with the AB blood type has always expressed both A and B, so their bodies will recognize any of the antigens, and never make antibodies to A or B.

When observing the ABO blood type, what are the alleles in a population and how many can a person carry at a time?

Alleles in a population: IA, IB, I, where one person can only carry two alleles at a time.

Why are some blood typing systems used more frequently than others?

Blood typing systems are used more frequently depending on the amount of variation within the population in that particular trait of red blood cells.

How can a researcher determine whether a person will react if they receive a blood transfusion?

Coagulation of blood in speckles after addition of anti-antibodies to the blood sample indicates that a rejection would occur during transfusion between the anti-antibodies and the antigens on the blood.

What is epistasis?

Epistasis is when one genotype is hiding or masking the genotype at a second locus.

Describe the pattern of dominance of the alleles of the ABO blood typing system.

IA = IB > I, where "=" represents codominance, where phenotypes associated with both genotypes are visible in the same person

What does the IA allele code for?

IA codes for the enzyme that attaches acetyl galactosamine to red blood cells.

What does the IB allele code for?

IB codes for the enzyme that attaches galactose to red blood cells.

Describe the differences in ABO blood types.

In each blood type, the surface proteins are the same, but modified in different ways.

What is the universal donor blood type?

O- is the universal donor, but can only receive from like blood type because a person with the O blood type will form antibodies against A, B, or AB blood if exposed to it.

What is recessive epistasis?

Recessive epistasis is when two or more genes contribute to a single phenotype and the resulting interaction decides the phenotype.

What is Rh factor?

Rh factor is the Rhesus factor. A person's blood is either positive or negative for the Rhesus factor.

Which is the dominant allele of Rh factor and what does this mean for people who are homozygous recessive?

Rh-positivity is dominant over Rh-negativity. If someone is Rh-negative, they cannot receive blood transfusions from someone who is Rh-positive because their body will develop antibodies to target the antigen, which is a foreign molecule.

What is the genotype of a person who has a non-functional H gene?

The recessive homozygous hh genotype (Bombay)

What does the ABO blood system describe?

The series of antigens that are present on red blood cells

If the father is heterozygous for the Rh-factor allele, what is the probability that the Rh-negative mother will react to her second baby's blood?

50%

What factors determine blood type?

Blood types are based on surface antigens on red blood cells, which may be proteins, carbohydrates, glycoproteins, or glycolipids.

What type of inheritance do blood types exhibit?

Blood types exhibit simple Mendelian inheritance.

What alleles has a person who is Rh-positive inherited?

Either D/d or D/D

Who can people with the Bombay genotype receive blood transfusions from?

Only other people who have the same genotype. They will react to blood with the H gene, because the antigen on the red blood cells contains a fructose that people with the recessive genotype do not have.

In what way can Rh factor differences between a mother who is Rh-negative and her baby be a problem?

Rh factor can be a problem for women with Rh-negative blood who are pregnant if their second fetus has a different Rh factor than they do. If the woman was Rh-negative and her first baby was Rh-positive, there would not be a problem because her body would not have come into contact with Rh-positive blood before, and would therefore not have an antibody to recognize it as foreign and target the fetus. If she came into contact with her baby's blood during birthing and her second baby had Rh-positive blood however, her body would have developed antibodies to the foreign blood and the fetus may be targeted for destruction.

What does the H gene code for?

The H gene codes for an enzyme that adds a fructose onto the surface antigen of the red blood cell. This fructose is essential for subsequent addition of the next monosaccharide by the enzymes coded for by the I allele.

What do the alleles at the I gene code for?

The alleles at the I gene code for enzymes that transfer alternate monosaccharides.