Question

ABO blood group is an example of

• A. Epistasis
• B. Multiple allelism
• C. Pleotropism
• D. Complementary genes

Answer 1

The correct option is B Multiple allelism

Multiple allelism: the state of having more than two alternative contrasting characters controlled by multiple alleles at a single genetic locus.
Multiple alleles is a type of non-Mendelian inheritance pattern that involves more than just the typical two alleles that usually code for a certain characteristic in a species. With multiple alleles, that means there is more than two phenotypes available depending on the dominant or recessive alleles that are available in the trait and the dominance pattern the individual alleles follow when combined together.
The human ABO blood type is a good example of multiple alleles. Humans can have red blood cells that are of type A (IA), type B (IB), or type O (i). These three different alleles can be combined in different ways following Mendel's Laws of Inheritance. The resulting genotypes make either type A, type B, type AB, or type O blood. Type A blood is a combination of either two A alleles (IA IA) or one A allele and one O allele (IAi). Similarly, type B blood is coded for by either two B alleles (IB IB) or one B allele and one O allele (IBi). Type O blood can only be obtained with two recessive O alleles (ii). These are all examples of simple or complete dominance.