Question

Which one of the following best describes polygenic inheritance?
A. ABO blood group in human and flower color of Mirabilis jalapa
B. Hair pigment of mouse and tongue rolling in human
C. Human eye color and sickle-cell anemia
D. Human height and color of skin and eyes

Answer 1

Hint: A "polygene” or "multiple gene inheritance" is a member of a group of non-epistatic genes that interact additively to influence a phenotypic trait. Polygenic inheritance occurs when one character is controlled by two or more genes. The genes are often large in quantity but small in effect.

Complete answer:
The human ABO blood group system describes codominance for a gene with multiple alleles. Codominance is a phenomenon in which alleles that do not show dominance recessive relationships are able to express themselves independently when present together. In incomplete dominance, the genes of an allelomorphic pair are not expressed as dominant and recessive but express themselves partially when present together in the hybrid. Mirabilis jalapa is an example of incomplete dominance.
Hair pigment of the mouse is an example of recessive epistasis. When the recessive allele of one gene masks the effects of either allele of the second gene, it is known as recessive epistasis.
Due to dominant traits with simple Mendelian inheritance, tongue rolling in humans can be observed in some people.
Human eye color is due to polygenic inheritance and sickle cell anemia is due to codominance.
Human height and color of skin and eyes occurs due to several genes, so it is an example of polygenic inheritance.
So, the answer is D, i.e., Human height and color of skin and eyes.

Note: Polygenic locus is included in the system of genes responsible for the genetic component of variation in a quantitative (polygenic) character. Polygenic characters show a continuous rather than discontinuous distribution.