Question:

Given below is a representation of a kind of chromosomal mutation. What is the kind of mutation represented?

Updated On: Jun 27, 2023

Deletion
Duplication
Inversion
Reciprocal translocation

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The Correct Option is C

Approach Solution - 1

Inversion involves a reverse order of genes in a part of chromosome. ABCDEFGH has been shown infigure where breakes occur between A and B as well as between D and E. Reunion at broken ends may lead to inversion of the segment BCD into DCB. In deletion, a section of chromosome is lost. In duplication a piece of chromosome is copied next to an identical section. In reciprocal translocation, a segment from a chromosome is translocated into a nonhomologous chromosome from which a segment is reciprocally transferred to the first chromosome.

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An inversion is the type of mutation that is represented. A chromosomal fragment inverts during inversion as a result of reattachment. Thus, the section B C D of a chromosome with the genes A B C D E F G H in linear order may become inverted. The new configuration will be AB CD CBE PGH. It is a kind of chromosomal aberration that involves two breaks in a chromosome, followed by a segment's reversal and the gene sequence in that segment. Contrary to paracentric inversion, pericentric inversion includes the centromere in the inverted region.

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Concepts Used:

Principles of Inheritance and Variation - Mutation

A Mutation is a change in the sequence of our DNA base pairs caused by numerous environmental stimuli such as UV light or mistakes during DNA replication. Germline mutations take place in the eggs and sperm and can be passed onto offspring, whereas somatic mutations take place in body cells and are not passed on.

Types of Mutations

There are three types of mutations, which are as follows:

Silent mutation

It refers to any change in DNA sequence that has no effect on the amino acid sequence in a protein or the functions that a protein performs. There is no phenotypic indication that a mutation has occurred.

Nonsense mutation

When there is a change in the sequence of base pairs due to a point mutation, that results in a stop codon. This leads to a protein that is either shortened or non-functional.

Missense mutation

A missense mutation occurs when a point mutation causes a change in the codon, which then codes for another amino acid.

The mutation is caused by the following factors:

Internal Causes

When DNA copies incorrectly, the majority of mutations occur. Evolution occurs as a result of all of these mutations. DNA makes a copy of itself during cell division. When a copy of DNA isn't flawless, it's called a mutation since it differs somewhat from the original DNA.

External Causes

When certain chemicals or radiations are used to break down DNA, it causes the DNA to break down. The thymine dimers are broken by UV radiation, resulting in altered DNA.