Write about the events of Pachytene and mention the significance of this phase.

Write about the events of Pachytene and mention the significance of this phase. 
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1 Answer

Answer :

Ans: Events of Pachytene:

1. The two chromatids of chromosome are clearly seen. Each bivalent has 4 chromatids and known as Pachytene tetrad. Chromatids of the same chromosome are called as Sister chromatids and that of different chromosomes as non-sister chromatids.

2. The arms of non sister chromatids are broken transversely by the action of Endonuclease and the broken pieces are reciprocally united by Ligase. In this way the genetic material exchanged and the phenomenon is called as Crossing Over.

3. The cross shaped structures seen at the place of crossing over are called as Chiasmata.

Significance: Crossing over leads to recombination of genetic characters. This is responsible for the origin of new species which is one of the causes of evolution.
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