Haematology: Blood Typing and Genetics

Vocabulary-style flashcards covering the genetics of blood types, inheritance patterns, antigens, antibodies, and relative abundance statistics.

Chromosome 9

The location of the human ABO gene in the genome.

Alleles

The three versions of the blood type gene, identified as A, B, and O.

Genotype

The genetic makeup of an organism, represented in blood typing by the specific combination of A, B, and O alleles.

Phenotype

The visible properties of an organism, which corresponds to a person's actual blood type (A, B, AB, or O).

Co-dominant

The genetic relationship between the "A" and "B" alleles when they are inherited together.

Recessive

The genetic status of the "O" allele relative to the "A" and "B" alleles.

Type A Genotypes

Represented by the allele combinations $I^A I^A$ or $I^A i$.

Type AB Genotype

Represented by the allele combination $I^A I^B$.

Type B Genotypes

Represented by the allele combinations $I^B I^B$ or $I^B i$.

Type O Genotype

Represented by the allele combination $ii$.

Antigen

A protein encoded by a specific enzyme that sits on the surface of the red blood cell (RBC).

Antibodies

Proteins found in the blood plasma that recognize and attack foreign molecules.

Blood Transfusion Clotting

The result of an immune response triggered when antibodies in the recipient's blood recognize antigens on donor blood cells as foreign.

Relative Abundance: Type O

$$43-45\%$$

Relative Abundance: Type A

$$40-42\%$$

Relative Abundance: Type B

$$10-12\%$$

Relative Abundance: Type AB

$$3-5\%$$

Rhesus Factor (Rh)

A protein found on the surface of red blood cells that is also found in Rhesus monkeys; it is expressed as either positive or negative.

Rh Positive Prevalence

Approximately $85\%$ of people.

O+ Statistics

$1$ in $3$ persons.

A- Statistics

$1$ in $16$ persons.

AB- Statistics

$1$ in $167$ persons.

Multiple Allelism

A condition exemplified by the blood type gene having three different alleles ($I^A$, $I^B$, and $i$).