Question

Inheritance of ABO blood groups is an example of
(a)Incomplete Dominance
(b)Dominance
(c)Codominance
(d)Both b and c

Answer 1

Hint: In the complete dominance, just one allele within the genotype is seen within the phenotype. In codominance, both alleles within the genotype are seen within the phenotype. In incomplete dominance, a mix of the alleles within the genotype is seen within the phenotype.

Complete answer:
ABO blood group is the best example of Codominance, Incomplete dominance and Dominance.
Codominance – an expression of phenotypes of both parents is called codominance.
Multiple allelism – Presence of greater than two alleles for a gene is called Multiple allelism.
Dominance – an expression of one allele in a pair of contrasting characters, in heterozygous organisms, is called Dominance.

Additional Information:
-All humans and many of the primates can be typed for the ABO blood group. There are principally four types of blood groups: A, B, AB, and O.
-Blood group O is the most common blood group among the 4.
-Receiving blood from the wrong ABO group can lead to the death of the person. For example, if someone with group B blood receives group A blood, their anti-A antibodies will attack the group A cells. This is the reason that group A blood must never be given to someone who has group B blood and vice versa.
-As group O red blood cells do not have any A or B antigens, it can safely be given to any other group, but can't receive blood from any of other blood groups, while a person with AB blood group can receive blood from any of these blood groups.

So, the correct answer is, ‘Both b and c.’

Note: -Codominance should not be confused with incomplete dominance. In incomplete dominance, there is a blending of characters to give a phenotype that is intermediate of both the characters i.e. red and white flowered parents will give pink flower offsprings.
-Whereas in the case of codominance, red and white flowered parents will give offsprings that have both red and white colour in them i.e. red and white spots.
-The phenomenon of incomplete dominance is shown by the Dog flower (Antirrhinum majus) in the inheritance of the colour of the flowers.