Blood Groups & Rh Factor PDF

# Blood Groups & Rh Factor ## Blood Groups - In 1900, a scientist named Karl Landsteiner discovered blood groups in humans. - In 1940, Landsteiner and Wiener discovered the Rh factor. - There are three types of alleles: $I^A$, $I^B$, and $i$ that are found in two loci. - These alleles produce...

# Blood Groups & Rh Factor ## Blood Groups - In 1900, a scientist named Karl Landsteiner discovered blood groups in humans. - In 1940, Landsteiner and Wiener discovered the Rh factor. - There are three types of alleles: $I^A$, $I^B$, and $i$ that are found in two loci. - These alleles produce the A, B, and O blood types respectively. - The type of glycolipid present on the surface of red blood cells is determined by the alleles present at the ABO locus. - Glycosyl transferases are enzymes that control the synthesis of glycolipids. - Antigens are glycolipids present on red blood cells. - Antibodies are proteins found in blood serum that attack specific antigens. - When the red blood cells of one person are mixed with the blood serum of another person, agglutination may occur. - If blood transfusions are performed between incompatible blood types, the individual may die. ## Blood Group Phenotype | Blood Group | Antigen | Antibody | Can Receive From | Can Donate To | Genotype | |---|---|---|---|---|---| | A | A | Anti - B | A, O | A, AB | $ I^A I^A$ or $ I^A i$ | | B | B | Anti - A | B, O | B, AB | $I^B I^B$ or $I^B i$ | | AB | A, B | None | A, B, AB, O | AB | $I^A I^B$ | | O | None | Anti - A, Anti - B | O | A, B, AB, O | $i i$ | * **AB** is the **universal recipient**. * **O** is the **universal donor.** ## Blood Transfusion An individual with blood type **A** can receive blood from individuals with blood type **A** or **O**, and can donate blood to individuals with blood type **A** or **AB**. ## Example Problems ** Problem 1** **Given** that a father has blood type A & is homozygous, and a mother has blood type B & is heterozygous. Find the blood type of their offspring. **Solution: ** The father's genotype: $I^A I^A$ The mother's genotype: $I^B i$ | | $I^A$ | $I^A$ | |---|---|---| | $I^B $ | $I^A I^B$ | $I^A I^B$ | | *i* | $ I^A i$ | $I^A i$ | **Therefore**, the offspring can have blood type **A** or **AB**, with a probability of 50% each. **Problem 2** **Given** that a father has blood type A & might be homozygous or heterozygous, and a mother has blood type B & is homozygous. Find the blood type of their offspring. **Solution:** If the father's genotype is $ I^A I^A$, the offspring will definitely have blood type AB. If the father's genotype is $ I^A i$, the offspring will have blood type AB or B, with a probability of 50% each. **Problem 3** **Given** that a father has blood type AB, and a mother has blood type A & is heterozygous. Find the blood type of their offspring. **Solution:** The father's genotype: $I^A I^B$ The mother's genotype: $I^A i$ | | $I^A$ | $I^B$ | |---|---|---| | $I^A $ | $I^A I^A$ | $I^A I^B$ | | *i* | $ I^A i$ | $I^B i$ | **Therefore**, the offspring can have blood type **A**, **AB** or **B** with a probability of 50% for A, and 25% each for AB and B. **Note:** Whenever a question does not mention the genotype, it is assumed to be heterozygous unless explicitly specified.