Question

Giant polytene chromosomes can be observed in

• A. Salivary glands of a larval fruit fly
• B. Amphibian oocytes
• C. Human egg
• D. Salivary gland of a man

Answer 1

Answer: (A)

Salivary glands of a larval fruit fly

Some tissues of certain organisms contain chromosomes, which differ significantly from the normal chromosomes in morphology and function. Such chromosomes are too large under normal conditions, thus are called salivary gland chromosomes. An example of giant chromosomes is polytene chromosomes. Polytene chromosomes are very common in salivary glands of insects. A generalised amplification of DNA due to repeated replication of DNA (chromonemata) without cell division and somatic pairing between the homologous chromosomes, gives rise to polytene chromosomes.

Hence, giant polytene chromosomes can be observed in salivary glands of a larval fruit fly. So, the correct answer is 'Salivary glands of a larval fruit fly'.