Genetic mutation

 Introduction to Genetic Mutation

Mutation is a healthy alteration in the genetic makeup of an individual. Genetic mutation leads to a structural or numerical manipulation of the DNA sequence resulting in the variation of species ”. Mutation is essential for the process of the gradual transformation of traits from one generation to another through evolution. Rarely, a mutation can cause aberration of the genes resulting in the permanent genetic disorders. Most often, mutation occurs when different alleles are inherited from the egg and the sperm. 

Table of Contents

1. Introduction to Genetic Mutation

2. Causes and risk factors of mutation 

3. Forms of mutation

4. Consequences of mutation- a genetic approach

5. Benefits of mutation

 

Causes and risk factors of mutation 

Mutations may occur naturally or may be induced by environmental factors. Some of the factors are the prolonged exposure of individuals to radiation, medication, or viral infections. Being pregnant too early (before 18 years) and too late( after 40 years) favour mutation as the chromosomal nondisjunction is increasingly common in these age groups. On the other hand, the age of the father ( sperm)  directly affects the sperm count and their energy to fertilize. This is evident in men aged more than 40 years. The aged sperms have a higher tendency to form a wrong nucleotide sequence. Some of the environmental factors like pollution, exposure to chronic ultraviolet radiation and chemical irritants increases the risk of mutation. Above all, a genetic error inherited from the parental genes can pass on to many generations.

 

Forms of mutation

There are 2 major forms of mutation; germinal mutation and somatic mutation. If the genetic abnormalities are formed during the process of fertilization, it is known as the germinal mutation. If the mutation occurs during fetal or embryonic development, it is a somatic mutation. In many cases, children are asymptomatic until they grow into their school age. Non-disjunction is the failure of chromosome pairs to separate. Non -disjunction results in the derangement of the physical structure of chromosomes. If the mutation affects the arrangement of chromosome arms, it is translocation. Inversion is another form of mutation where the order of nucleotides are placed in a reverse mannerA bit rare and less profound form of mutation is the deletion of part of a chromosome. Deletion can easily hamper the order of gene arrangement thereby causing mutation. Mutation can affect the victims both genotypically and phenotypically, sometimes they take a serious form where gene therapy may not work.

 

Nonsense mutation  

 

 

 

Missense mutation

 

 

Insertion Defect

 

 

Frameshift Mutation

 

 

Duplication Error

 

 

Deletion Error

Mutation types-Images by US National Library of Medicine

 

Consequences of mutation- a genetic approach

  1.  Mutations interfere with protein synthesis by altering the nucleotides responsible for amino acid formation.

  2. Changes in the nucleotide sequence cause chronic conditions such as sickle cell disease, haemophilia, and some congenital illnesses of the heart.

  3. In some cases, gene mutations can cause stillbirth (baby is born dead).

  4. Kids suffered from mutation are substantially affected in terms of the level of intelligence.

  5. Affected children experience poor physical, emotional, intellectual and social development.

  6.  One of the common causes of congenital ( by birth) cancer is a mutation. Many cell studies have proved the correlation between cancer and genes.

 

Benefits of mutation

Nevertheless, most of the mutations are harmful, few of the healthy genetic alterations could benefit the species. Mutations produce a new version of proteins that will enable the organisms to adapt to drastic changes within the environment. In other words, they increase the organism’s chances of survival and reproduction. It is believed that thick fur on the animal skin, especially in the polar region, is a result of natural mutation. Another example is bacteria that can survive in the presence of antibiotic drugs is as a result of the mutant gene. 

 



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