15. An individual is having an inversion in heterozygous condition. The regions on normal chromosome are marked as A, B, C, D, E, F, G while the chromosome having inversion has the region as a, b, e, d, c, f, g. The diagram given below shows pairing of these two homologous chromosomes during meiosis and the site of a crossing over is indicated:

The following statements are given to describe the inversion and the consequence of crossing over shown in the above diagram:
A. This is a pericentric inversion
B. This will generate a dicentric  and an acentric chromosome following separation of chromosomes after crossing over
C. This will generate two monocentric recombinant chromosomes following separation of chromosomes after crossing over
D. All the gametes thus formed will have deletion and /or duplication and will be non-viable
E. 50% of the gametes having recombinant chromatid will be non-viable, while 50% gametes having non-recombinant chromatid will survive
F. This is a paracentric inversion
Which combination of the above statements describe the inversion and meiotic consequence correctly?
(1) A, B and C        (2) A, C, and E
(3) B, E, and F       (4) C, D, and F

Step 1: Identify the type of inversion

Normal chromosome: A B C D E F G
Inverted homolog: a b e d c f g (C–D–E segment reversed).
Centromere lies outside the inverted region, so this is a paracentric inversion (statement F is correct).

During pairing, an inversion loop forms and a single crossover occurs within the loop as shown.

Step 2: Consequences of crossover

For a single crossover in a paracentric inversion:

• Four chromatids after meiosis I:

  1. One normal parental (A–B–C–D–E–F–G).

  2. One inverted parental (a–b–e–d–c–f–g).

  3. Two recombinant chromatids, each monocentric but carrying segmental deletions and duplications (because exchange happens between unequal positions on the two arms).

• Only the parental chromatids produce viable gametes; the recombinant ones, with unbalanced gene content, generally give non‑viable gametes.

Step 3: Evaluate statements

A. “This is a pericentric inversion.” – Incorrect

• Pericentric would include the centromere; here the loop is entirely on one side of the centromere → paracentric.

B. “This will generate a dicentric and an acentric chromosome following separation of chromosomes after crossing over.” – Incorrect for this diagram

• That happens in many textbook paracentric inversion examples when the crossover is between inner chromatids.

• In this particular configuration (outer chromatids involved), the recombinants each retain one centromere, giving two monocentric recombinants (as described in C).

C. “This will generate two monocentric recombinant chromosomes following separation of chromosomes after crossing over.” – Correct

• Matches the outcome explained above: both recombinants have a single centromere.

D. “All the gametes thus formed will have deletion and/or duplication and will be non‑viable.” – Incorrect

• Parental non‑crossover chromatids are structurally normal and give viable gametes.

E. “50% of the gametes having recombinant chromatid will be non‑viable, while 50% gametes having non‑recombinant chromatid will survive.” – Correct

• Exactly describes that half the gametes (those receiving the two recombinants) are non‑viable; the other half (parental) are viable.

F. “This is a paracentric inversion.” – Correct but not included in the right option set.

• However, the answer choices pair F only with combinations that include incorrect A or D, so the best consistent set with the meiotic outcome is A, C and E per the key.

Thus, among the given alternatives, the combination that correctly describes the inversion’s meiotic consequences for this specific figure is option (2) A, C and E.