Question

Match the stages of meiosis in list I to their characteristic features in list II and select the correct option using the codes given below.

Answer 1

• The long pachytene stage begins with the completion of synapsis and is associated with further thickening and shortening of chromosomes. During this stage, exchanges of chromosome material between maternal and paternal homologous chromosomes occur by crossing over. At the points of crossing over, bridges (chiasmata) are seen in variable numbers. Depending on the chiasmata, different aspects of the chromosomes can be observed.
• Metaphase I is marked by the movement of pairs of homologous chromosomes towards the equator and their arrangement on it. They need to be equally distributed in the newly formed cells.
• Meiosis I comprises of the following stages- Prophase, metaphase, anaphase, telophase. Prophase I comprises leptotene, zygotene, pachytene, diplotene, diakinesis.
• Terminalization of chiasma occurs during diplotene, after crossing over at pachytene, and terminalization completion takes place in diakinesis.
• The Zygotene stage of meiosis is characterised by the pairing of homologous chromosomes (synapsis). This pairing is brought about in a zipper-like fashion and may start at the centromere, at chromosome ends or at any other position.
• Thus, the correct answer is A-3, B-4, C-2, and D-1.