Main Profile

At A Glance

4.3.4 Describe ABO blood groups as an example of codominance and multiple alleles

There are 3 alleles involved in the determination of blood groups as shown on the video. They determine the antigens present on red blood cells. 'I^A' gives A antigens. 'I^B' gives B antigens and 'i' gives no antigens.However, the genotypes for a given individual's blood group can only be determined by two of the three alleles. The possible genotypes for each blood group (phenotypes) are:Blood group A: I^A I^A or I^A iBlood group B: I^B I^B or I^B iBlood group AB: I^A I^BBlood group O: i iIn the example a person of blood type AB (genotype I^A I^B) is crossed with a person heterozygous for blood type A (I^A i). The gametes from the person with blood type AB are either I^A or I^B whereas the person of blood type A can produce gametes either I^A or i. Once the punnett square is compete the genotypic and phenotypic ratios can be deduced:Genotypic ratio: 25% I^A I^A : 25% I^A i : 25% I^A I^B: 25% I^B I^iPhenotypic ratio: 50% Blood type A : 25% Blood type AB : 25% Blood type O
Length: 02:26

Contact

Questions about 4.3.4 Describe ABO blood groups as an example of codominance and multiple alleles

Want more info about 4.3.4 Describe ABO blood groups as an example of codominance and multiple alleles? Get free advice from education experts and Noodle community members.

  • Answer

Ask a New Question