Question

Which of the following chromosomal mutation are most likely to take place when homologous chromosomes are undergoing synapsis?

• A. Inversion and translocation
• B. Deletion and duplication
• C. Inversion and deletion
• D. Translocation and duplication

Answer 1

The correct option is B

Deletion and duplication

The correct option is B:

Explanation of the correct option:

1. Synapsis is the pairing of the human chromosomes from each parent during the prophase I of meiosis.
2. Deletion and duplication usually occur during the synapsis process.
3. In deletion, a part of a chromosome is lost, thus decreasing the chromosomal length.
4. Whereas in duplication, a segment is copied and reattached, thus increasing chromosomal length.

Explanation of the incorrect options:

Option A:

1. Inversion is the process in which the segment of the chromosome breaks and gets reattached in the reverse direction.
2. Whereas translocation occurs during mitosis when broken ends of two non-homologous chromosomes are joined together.

Option C:

1. Inversion is the process in which the segment of the chromosome breaks and gets reattached in the reverse direction.
2. Whereas, in deletion, a part of a chromosome is lost.

Option D:

1. Translocation occurs when broken ends of two non-homologous chromosomes are joined together.
2. Whereas, in duplication, a segment is copied and reattached, thus increasing chromosomal length.

Final answer: Deletion and duplication are the two most common chromosomal mutations during the synapsis of homologous chromosomes.