Difference Between Frameshift Mutation and Base Substitution Mutation

The key difference between frameshift mutation and base substitution mutation is that frameshift mutation is an insertion or deletion of a base pair or base pairs from a DNA sequence of a gene that causes changes in the open reading frame while base substitution mutation is the exchange of one nucleotide from another nucleotide in a DNA sequence.

Changes that occur in DNA sequences can result in different types of mutations. As a result of mutation, a particular gene sequence can be altered and result in varying effects such as cancers, genetic diseases, birth defects, infertility problems, etc.  There are different factors affecting mutations. UV and chemical agents are the major factors among them.

CONTENTS

1. Overview and Key Difference
2. What is a Frameshift Mutation
3. What is a Base Substitution Mutation
4. Similarities Between Frameshift Mutation and Base Substitution Mutation
5. Side by Side Comparison – Frameshift Mutation vs Base Substitution Mutation in Tabular Form
6. Summary

What is a Frameshift Mutation?

A frameshift mutation is a type of mutation that occurs due to insertion or deletion of a base pair or base pairs. It changes the reading frame of the gene and expresses an incomplete or incorrect protein. Generally, nucleotide triplets make codons. Each codon codes for a specific amino acid. Upon insertion or deletion, nucleotides in triplets shift and show a difference compared to the original sequence. Wrong codon sequence results in a wrong amino acid during the translation process. In the end, it produces a different amino acid sequence. In other words, frameshift mutation produces an incorrect protein at the end of the gene expression.

Figure 01: Frameshift Mutation

Frameshift mutations lead to several complications including Tay-Sachs disease, Crohn’s disease, Cystic fibrosis, HIV and cancer. Frameshift mutation can occur randomly. It also can occur due to external stimuli such as chemical agents.

What is Base Substitution Mutation?

Base substitution mutation is the alteration of a DNA sequence due to the exchange of a nucleotide with another nucleotide. One base exchanges with another, so, it is a type of a point mutation. Some single base mutations are silent mutations. However, some causes diseases. For example, a single substitution in the beta haemoglobin gene causes life-threatening disorder; for example, sickle cell anaemia due to alteration of single amino acid. Furthermore, base substitutions produce incomplete proteins which are non-functional.

Figure 02: Base Substitution Mutation

Chemical agents induce base substitution mutations. Moreover, UV light can also cause single base substitution mutations.

What are the Similarities Between Frameshift Mutation and Base Substitution Mutation?

• Frameshift mutation and base substitution mutation are two types of mutations occurring in DNA sequences.
• They change the genetic makeup of an organism.
• Moreover, they can result in unwanted or malfunctional proteins.
• Both are caused by chemical agents, radiation, UV, etc.

What is the Difference Between Frameshift Mutation and Base Substitution Mutation?

Insertions and deletions cause frameshift mutations, while the exchange of one base from another (substitution) causes base substitution mutations. So, this is the key difference between frameshift mutation and base substitution mutation.

Below infographic summarizes the difference between frameshift mutation and base substitution mutation.

Summary – Frameshift Mutation vs Base Substitution Mutation

Frameshift mutation causes changes in the reading frame of a gene, resulting in the expression of incorrect proteins. Insertions and deletions are the main reasons for frameshift mutations. Base substation mutation causes changes in the DNA sequence due to the exchange of one base from another. They also produce incorrect proteins at the end if the mutation is not silent. Thus, this summarizes the difference between frameshift mutation and base substitution mutation.

Reference:

1. “Frameshift Mutation – Definition, Examples & Effects.” Biology Dictionary, 28 Apr. 2017, Available here.
2. “Genetic Mutation.” Nature News, Nature Publishing Group, Available here.

Image Courtesy:

1. “Frameshift deletion (13062713935)” By Genomics Education Programme – Frameshift deletion (CC BY 2.0) via Commons Wikimedia
2. “Mutation par substitution” By Lln.gyenes lfv – Own work (CC BY-SA 4.0) via Commons Wikimedia

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