CUET Preparation Today
Match Column 1 with Column 2 :
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A-ii, B-iv, C-i, D-iii A-ii, B-iv, C-iii, D-i A-ii, B-iii, C-i, D-iv A-iii, B-iv, C-i, D-ii |
A-ii, B-iii, C-i, D-iv |
The correct answer is Option (3) –A-ii, B-iii, C-i, D-iv
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 of human polygenic inheritance are skin colour, eye colour.
Haemophilia : This sex linked recessive disease, which shows its transmission from unaffected carrier female to some of the male progeny has been widely studied. In this disease, a single protein that is a part of the cascade of proteins involved in the clotting of blood is affected. Due to this, in an affected individual a simple cut will result in non-stop bleeding. Sickle-cell anaemia : This is an autosome linked recessive trait that can be transmitted from parents to the offspring when both the partners are carrier for the gene (or heterozygous). The disease is controlled by a single pair of allele, HbA and HbS. Out of the three possible genotypes only homozygous individuals for HbS (HbSHbS) show the diseased phenotype.
The inheritance of flower colour in the dog flower (snapdragon or Antirrhinum sp.) is a good example to understand incomplete dominance. In a cross between true-breeding red-flowered (RR) and true- breeding white-flowered plants (rr), the F1 (Rr) was pink. |
