Question

Polytene chromosomes are formed by which of the following?

• A. Endoreduplication of chromosomes
• B. Somatic pairing of homologous chromosomes
• C. Somatic pairing of non-homologous chromosomes
• D. Germinal pairing of non-homologous chromosomes

Answer 1

The correct option is A Endoreduplication of chromosomes

Polytene chromosomes are oversized chromosomes and hence are also called as giant chromosomes. They are found in the salivary glands of insects. The chromosomes of the larval salivary glands undergo many rounds of endoreduplication. During endoreduplication, the chromosome undergoes repeated division without the cytoplasmic division. Hence, chromosome number is doubled and they do not segregate. It causes increase in the volume of cell's nuclei.

Thus, the correct answer is option A.