Match List I with List II
| LIST I | LIST II |
|---|---|
| A. Phenotype reflects the contribution of each allele | I. Pleiotropy |
| B. Multiple phenotypic expressions by a single gene | II. Linkage |
| C. Generation of non-parental gene combinations | III. Polygenic inheritance |
| D. Parental gene combinations higher than non-parental type in F2 progeny | IV. Recombination |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → A-III, B-I, C-IV, D-II
(A) Phenotype reflects the contribution of each allele — this matches (III) Polygenic inheritance. In a polygenic trait such as human skin colour, several genes act together and each allele adds a little, so the phenotype is the sum of all of them.
(B) Multiple phenotypic expressions by a single gene — this matches (I) Pleiotropy. A pleiotropic gene affects more than one trait; in phenylketonuria one faulty gene causes mental retardation and lighter hair and skin.
(C) Generation of non-parental gene combinations — this matches (IV) Recombination. Crossing over during meiosis gives new combinations of genes that neither parent had.
(D) Parental gene combinations higher than non-parental type in F2 progeny — this matches (II) Linkage. Genes lying close together on one chromosome tend to stay together, so parental types outnumber the recombinants, as Morgan found in Drosophila.