Question

Match the terms in Column I with their description in Column II and choose the correct option:

$\begin{array}{cccc}& ColumnI& & ColumnII\\ A.& Dominance& \left(i\right)& Manygenesgovernasinglecharacter\\ B.& Codominance& \left(ii\right)& Inaheterozygousorganismonlyonealleleexpressesitself\\ C.& Pleiotropy& \left(iii\right)& Inaheterozygousorganismbothallelesexpressthemselvesfully\\ D.& Polygenicinheritance& \left(iv\right)& Asinglegeneinfluencesmanycharacters\end{array}$

• A. (a) - (ii) (b) - (i) (c) - (iv) (d) - (iii)
• B. (a) - (ii) (b) - (iii) (c) - (iv) (d) - (i)
• C. (a) - (iv) (b) - (i) (c) - (ii) (d) - (iii)
• D. (a) - (iv) (b) - (iii) (c) - (i) (d) - (ii)

Answer 1

The correct option is B (a) - (ii) (b) - (iii) (c) - (iv) (d) - (i)

Dominance in genetics is a relationship between alleles of one gene, in which the effect on the phenotype of one allele masks the contribution of a second allele at the same locus. The first allele is dominant and the second allele is recessive. Example: In garden pea, tall is dominant over short plant.

Codominance is a form of dominance wherein the alleles of a gene pair in a heterozygote are fully expressed. This results in offspring with a phenotype that is neither dominant nor recessive. Example: I${}^A$ and I${}^B$ in human blood groups are codominant.

Pleiotropy occurs when one gene influences two or more seemingly unrelated phenotypic traits. Example: Phenylketonuria.

Polygenic inheritance occurs when one character is controlled by two or more genes. Often the genes are large in quantity but small in effect. Examples: Height and skin color in human.