​An individual is heterozygous for a reciprocal translocation as shown below in the given diagram:​

The following statements are made about segregation of such chromosomes during meiosis and gamete formation:

A. The complexly paired 4 chromosomes fail to segregate, pass into one cell at anaphase I and the cell eventually dies.
B. Chromosomes pair between regions of maximum homology keeping the translocated part unpaired and a normal meiosis occurs.
C. One of the ways the chromosomes aggregate is by alternate segregation (N1, N2 moving to one pole and T1, T2 moving to the other pole).
D. Alternate segregation produces non-viable gametes.
E. Reciprocal translocations are considered as crossover suppressors as no gametes with crossover product are produced.

Select the option from the following that describes the meiotic consequences of such translocation correctly:

Correct option is B

Explanation-

​Reciprocal translocation occurs when non-homologous chromosomes exchange segments.
If an individual is heterozygous for this translocation, they have:
                                         1.    One normal set of chromosomes (N1 & N2)
                                         2.    One translocated set (T1 & T2)
This creates a cross-shaped (quadrivalent) structure during meiosis I due to pairing between homologous regions.
Segregation Types in Meiosis I
There are three types of segregation for reciprocal translocation quadrivalents:
1. Alternate Segregation 
N1 + N2 go to one pole, T1 + T2 go to the other. Each gamete gets one complete set of genetic information. This produces viable gametes.
2. Adjacent-1 Segregation 
N1 + T2 or T1 + N2 go to one pole. Each gamete gets duplicated and deficient regions. This produces non-viable or inviable gametes.
3. Adjacent-2 Segregation (rare) 
Homologous centromeres go to same pole (e.g., N1 + T1 or N2 + T2). This also leads to duplication and deficiency → non-viable.

Statement A -The complexly paired 4 chromosomes fail to segregate, pass into one cell at anaphase I and the cell eventually dies.
Incorrect — This is rare and not typical. Chromosomes do segregate, though not always normally.

Statement B -  Chromosomes pair between regions of maximum homology keeping the translocated part unpaired and a normal meiosis occurs.
 Incorrect — The chromosomes form a quadrivalent, not unpaired segments, and meiosis can produce abnormal gametes.

Statement C -One of the ways the chromosomes segregate is by alternate segregation (N1, N2 moving to one pole and T1, T2 moving to the other pole).
Correct — This is the alternate segregation, leading to balanced, viable gametes.

Statement D -Alternate segregation produces non-viable gametes.
Incorrect — Alternate segregation produces viable gametes because all genetic material is present.

Statement E - Reciprocal translocations are considered as crossover suppressors as no gametes with crossover product are produced.
Incorrect — Crossovers can still happen, but may result in duplications/deletions. They are not true crossover suppressors.

Correct Answer is option b - C only