Question

1. During which phase does crossing over between the homologous chromosomes (paternal and maternal homologs) occur?

A.            interphase      

B.            prophase I          

C.            prophase II

D.            metaphase I      

E.            metaphase II

Answer 1

Here, the correct option is B.  prophase I

Explanation -

Generally, the crossing over takes place in the meiosis cell division and not in the mitosis. Meiosis is again divided into two stages: meiosis I and meiosis II. Meiosis I consists of prophase I, metaphase I, anaphase I and telophase I. During the pachytene stage of the prophase I of the meiosis I the crossing over takes place.

Crossing over is the event in which the genetic material present in the homologous chromosomes (one maternal chromosome and one paternal chromosome) takes place. Due to this crossing over the offspring produced will be different from the both the parents. It will have both the characters of the mother and the father.

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