Arrange the following events of meiosis in correct sequence (i) Crossing over (ii) Synapsis (iii) Terminalisation of chiasmata (iv) Disappearance of nucleolus
- (i), (ii), (iii), (iv)
- (ii), (iii), (iv), (i)
- (ii), (i), (iv), (iii)
- (ii), (i), (iii), (iv)
Answer
(4) (ii), (i), (iii), (iv)
Solution
As per NCERT, prophase I of meiosis is divided into leptotene, zygotene, pachytene, diplotene and diakinesis.
⇒ Zygotene: homologous chromosomes pair (synapsis) — (ii)
⇒ Pachytene: crossing over between non-sister chromatids — (i)
⇒ Diakinesis: terminalisation of chiasmata — (iii); by the end of diakinesis the nucleolus disappears and the nuclear envelope breaks down — (iv)
∴ Correct sequence: (ii), (i), (iii), (iv)
Answer: (4)