Homozygous purelines in cattle can be obtained by :
- mating of related individuals of same breed
- mating of individuals of different species
- mating of individuals of different breed
- mating of unrelated individuals of same breed
Answer
(1) mating of related individuals of same breed
Solution
As per NCERT, inbreeding refers to the mating of more closely related individuals within the same breed for 4–6 generations.
Inbreeding increases homozygosity; hence it is necessary if we want to evolve a pureline in any animal.
Mating of different species (interspecific hybridisation), of different breeds (cross-breeding) and of unrelated animals of the same breed (out-crossing) are forms of out-breeding, which increase heterozygosity.
Answer: (1)