Q. 10 - Biology

Question

Assume a pericentric inversion occurred in one of two homologs prior to meiosis. The other homolog remains normal. During meiosis, what structure—if any—would these homologs assume in order to pair accurately along their lengths? 

a. V formation 

b. cruciform 

c. loop 

d. pairing would not be possible 

Step-by-Step Solution

Answer

The correct option is (c). 

Step 1. Introduction

A pericentric inversion is  a rearrangement of chromosome in which a chromosomal segment reversed end-to-end.

Step 2. Explanation of correct and incorrect option

During pericentric inversion the length of chromosome arm is altered i.e. both arms become asymmetric (one short, one long). Thus in order to have point to point synapsis (contact) during meiosis the longer homologue needs to form a loop and the shorter one is around the loop.

If the homologue assume any other structure point to point synapsis is unlikely.

Hence loop structure is best for correct alignment. Thus option (c) is correct and rest are incorrect.