Correct option is D
The correct answer is: 4. A, B, C, D and E
Explanation:
The figure shows homologous chromosomes paired during meiosis, with one event of recombination occurring between them. Let's break down each interpretation:
A. The individual is heterozygous for an inversion:
The diagram shows a recombination event that involves chromosome regions being inverted. The presence of a crossover involving an inversion indicates that the individual is heterozygous for an inversion, where one chromosome carries the inversion, while the other does not.
B. The figure depicts a paracentric inversion:
Paracentric inversions involve the inversion of a chromosomal segment that does not include the centromere. The diagram fits this description, as the inversion occurs without the centromere being involved.
C. After recombination at Anaphase I, a dicentric and an acentric chromosome will be formed:
During Anaphase I, the crossover at the inverted region would result in the formation of dicentric chromosomes (with two centromeres) and acentric chromosomes (without a centromere). These are typical outcomes after recombination involving inversions.
D. At Anaphase II the recombinant chromatids will have large deletion or duplication:
In Anaphase II, the dicentric and acentric chromosomes will separate, often leading to deletion or duplication of chromosomal material because of the mis-segregation of these chromosomes.
E. Inversions are often considered as crossover suppressors because crossover products do not survive:
Inversions prevent the normal exchange of genetic material between chromosomes during meiosis, thus acting as crossover suppressors. The products of crossover in inverted regions are typically non-viable due to chromosomal abnormalities such as dicentric and acentric chromosomes.
Information Booster:
Heterozygous inversion occurs when one homologous chromosome contains an inversion while the other does not.
Paracentric inversions do not include the centromere in the inverted segment, causing different recombination outcomes compared to pericentric inversions (which include the centromere).
Dicentric chromosomes (two centromeres) and acentric chromosomes (no centromere) are formed as a result of recombination within an inverted region.
The mis-segregation of dicentric and acentric chromosomes often leads to deletions or duplications of genetic material during Anaphase II.
Inversions act as crossover suppressors, preventing effective homologous recombination and producing non-viable crossover products.
Recombination in inverted regions can lead to severe chromosomal instability, resulting in loss of viable offspring or genetic disorders.
