A chromosome has the following segments, where + represents the centromere: A B C + D E F G H What type of chromosomal aberration does the following chromosome have? A B C + D G F E H

Answer: A paracentric type of inversion

Explanation:

Inversion occurs when a given segment of chromosome is excised and then reinserted at an orientation 180 degrees from the normal orientation. This paracentric type of inversion does not include the centromere.

Paracentric inversions

Explanation:

Inversion is a type of mutation in which the chromosomal segment breaks and rearranges itself and rotates at an angle of about 180°.

Since the rotation is at 180° and the sequence is inverted therefore the mutation is known as the inversion. The inversion is of two types: pericentric (centromere is involved) and paracentric (centromere is not involved).

In the given question,

The normal sequence is A B C + D E F G H

The abnormal sequence is A B C + D G F E H

+ denotes the centromere.

Since the sequence D E F G H is reverse but has not involved the centromere, therefore, the inversion is paracentric.

Thus, paracentric inversion is correct.