Crossing over doesn’t take place ________________ A. Between


Crossing over doesn’t take place ________________

A. Between two sister chromatids

B. Between two non-sister chromatids

C. For recombination repair

D. Between three chromatids

This question was posed to me in final exam.

My question is based upon Meiosis Prophase 1 : Pachytene topic in chapter Chromosomal Changes During Meiosis of Cytogenetics

Right choice is D. Between three chromatids

The best I can explain: Crossing over can occur between two non-sister chromatids as well as for recombinational purpose. Crossing over also occurs between sister chromatids but it is of less significance as they have same genetic constitution. Three chromatids single cross over is not possible.