What results to polyploidy?

Failure of cytokinesis after telophase

The correct answer is Option (1) → Failure of cytokinesis after telophase

Polyploidy (having more than two complete sets of chromosomes) arises due to:

Failure of cytokinesis after telophase:

• The cell undergoes chromosome duplication but fails to divide, resulting in a cell with double the chromosome number (e.g., 4n instead of 2n).

Other Options:

• Failure of chromatid segregation: Causes aneuploidy (abnormal chromosome number, e.g., trisomy), not polyploidy.
• Both 1 and 2: Incorrect (only cytokinesis failure leads to polyploidy).
• Retrovirus: No direct role in polyploidy formation.

Key Example:

• Autopolyploidy in plants (e.g., wheat, bananas) often results from cytokinesis failure.