Question

What is crossing over . Name the enzyme responsible for it?

Answer 1

Crossing over takes place in meiosis type of cell division.
This event occurs in Pachytene phase of Prophase 1 of Meiosis 1 .
During this event the non sister chromosomes of homologous chromosomes exchange their genes which is responsible for genetic variations .
The enzymes involved in crossing over  1) Recombinase is the major enzyme regulating recombination event  2) Endonuclease  3) Ligase enzyme Endonuclease is responsible for breakage of 2 non-sister chromatids at corresponding sites.

Answer 2

Crossing over is basically genetic recombination process. It is a process  where homologous chromosomes pair up with each other. They could exchange different segments or parts of them between two non homologous chromosomes. The time in which it is generally occurs is between the prophase 1 and metaphase 1 in the process of meiosis. Crossing over occur over fifty seven times in males and about seventy five times in female during the process of meiosis.