Question

Which of the following is true?

(a) Zygotene is the phase preceding diplotene

(b) DNA replicated in zygotene is incorporated in chromosome 5-6 days later

(c) Synaptonemal complex formed is longer than the physical length of chromosomes itself

(d) The pairing of chromosomes forces the DNA to replicate

This question was posed to me in an international level competition.

Origin of the question is Meiosis Prophase 1 : Zygotene topic in portion Chromosomal Changes During Meiosis of Cytogenetics

Answer 1

The correct option is (b) DNA replicated in zygotene is incorporated in chromosome 5-6 days later

The explanation is: DNA replicated in zygotene phase is not immediately incorporated in the chromosome but it takes 5-6 days. While zygotene is followed by pachytene and the synaptonemal complex is shorter than the chromosome itself. The pairing follows replication and not vice versa.