Question

If two persons with 'AB' blood group marry and have a sufficiently large number of children, these children could be classified as ‘A’ blood group : 'AB' blood group :'B' blood group in 1:2:1 ratio. Modern technique of protein electrophoresis reveals the presence of both 'A' and 'B' type proteins in 'AB' blood group individuals. This is an example of?

• A. incomplete dominance
• B. codominance
• C. complete dominance
• D. partial dominance

Answer 1

The correct option is B

codominance

The correct option is B

Explanation of the correct option:

1. Multiple allelism and codominance occur within the ABO blood group system in humans.
2. However, only two alleles are necessary for a gene to be expressed in a human at any one time.
3. When two distinct alleles express themselves simultaneously in a heterozygote, the phenomenon is known as co-dominance.
4. The ABO blood group system was created by Karl Landsteiner and is well known.

Explanation of the incorrect option:

Option A:

1. When both alleles of a gene are only partially expressed at a locus, it is known as incomplete dominance.
2. This sort of gene interaction frequently produces an intermediate or distinct phenotype.
3. For instance, the gene for the colour red predominates over the allele for the colour white in roses.

Option C:

1. When one allele, or "version," of a gene totally conceals another, this is known as complete dominance.
2. It is said that the trait that is expressed "dominates" the trait that is not expressed.
3. The majority of living things are diploid, meaning that each gene is present in two copies, one from each parent.

Option D:

1. When both alleles of a gene are only partially expressed at a locus, it is known as incomplete dominance.
2. This sort of gene interaction frequently produces an intermediate or distinct phenotype.

Final answer: Codominance is the correct option.