Question

In Drosophila, crossing over occurs only in females.

• A. True
• B. False

Answer 1

The correct option is A True

• Crossing over is defined as a mechanism of the recombination of the genes occurring due to interchange of chromosomal segments at the time of pairing.
• No crossing over has been observed in male Drosophila as they possess unusual prophase I of meiosis in which no synaptonemal complexes and chiasmata develop. The synaptonemal complex proteins are required for the accurate pairing of homologous chromosomes to facilitate crossing over.
  
• Therefore crossing over in Drosophila is observed in females only.