Question

Write short notes on:
(i) Atavism
(ii) Protoplast fusion
(iii) Rh factor

Answer 1

(i) Atavism is the reappearance or refunctioning of certain ancestral characters after several generations, which have either completely disappeared or greatly reduced. For example, a baby born with a short tail.

(ii) Protoplast fusion is the fusion of protoplasts of two plant cells to form a single cell with multiple nuclei. It is done with the help of certain compounds such as PEG-polyethylene glycol or by electrofusion. This provides a chance for an extended variety of hybrid plants between nonrelated species and genera e.g., hybrids of wheat and rye, and turnip and cabbage.

(iii) Rh factor was first discovered in Rhesus monkey. A person with Rh antigen on the surface of red blood corpuscles is known as Rh positive and the person who lack this antigen are considered as Rh negative.