Harmful and Neutral Effects

Key Concepts

• Mutation
• Harmful Effects
• Neutral Effects
• Albinism
• Polyploidy

Introduction:

Harmful and Neutral Effects, Mutation is a change in the genetic material of an organism. 

Mutations have beneficial, harmful as well as neutral effects. 

Beneficial mutations lead to evolution, and survival of the fittest. 

However, most of the mutations are harmful and lead to genetic disorders. 

Explanation: 

Harmful Mutations: 

Mutations that lead to changes in genes that further produces unusual protein or alter the function of that protein adversely are called harmful mutations. 

These mutations are not useful and do not lead to evolution. 

The organisms with harmful mutations do not survive long.  

Example 1: 

Albinism in organisms is an example of harmful mutation that fails to produce melanin, a useful pigment that protects organisms against the harmful radiation of the sun. 

Hence, the organisms are white in color. They have a high risk of skin cancer and low vision. 

Also, organisms that show albinism fail to escape from their predators as they appear easily against background. They serve as easy targets to their predators. 

 These organisms fail to survive the fittest and die very soon. 

Example 2: 

Hemophilia is a bleeding illness caused by a mutation in the gene that fails to produce blood clotting factor. 

Hence, people with this disorder have excessive bleeding during injuries. 

It also causes internal bleeding, painful joints, and gums. 

Example 3: 

Polyploidy in organisms is a condition of having more than two sets of chromosomes.  

This leads to the production of extra limbs, two heads, webbed feet, extra fingers etc. in animals and humans. 

These organisms have difficulty in surviving and die soon. 

Example 4: 

Cancer is a leading cause of death worldwide.  

It is caused due to mutations that lead to abnormal growth of cells in the body that grow uncontrollably and form tumors. 

These cells halt the function of normal body cells that lead to systemic failures in body and death of the person. 

Example 5: 

Sickle cell anemia is a disease where the shape of red blood cells is not disc shaped, but sickle shaped, or crescent moon shaped that leads to lower hemoglobin and low blood levels in people. 

People with this disease are weak, look pale and sickle shaped cells get stuck together and block blood vessels. 

Neutral Mutations 

The changes in the DNA or genetic material that are neither useful nor harmful to the organism, the effect is neutral. 

These mutations change the phenotype that does not affect adaptation nor reproduction. 

Example: 1 

Different eye color is observed in human beings due to mutation. 

This change in the eye color does not have any effect on reproduction or survival.  

In most cases the eye color is inherited from parents. 

Example: 2 

Different ear lobes in humans. 

Humans have either free or attached ear lobes. 

These changes are due to mutation in a single gene responsible for ear lobes. 

The presence of attached or free lobes does not affect humans. 

It is also studied that humans have a wide number of neutral mutations that do not affect them at all. 

Example: 3 

Different fur color in animals is a type of neutral mutation that we see around. 

Dogs of the same breed or dogs from the same parent have different fur color or textures. 

This does not affect the organism in its growth and reproduction. 

Example: 4 

Polyploidy in plants is an example of neutral mutation. 

Where flowers of the same plant show difference in color or show two colors. 

Such types of neutral mutations do not affect the plant and if the owner likes it, he further produces these kinds of plants by grafting and other vegetative propagation methods. 

These may be of commercial value and turn out to be beneficial. 

Summary:

• Mutation is a variation in the genetic material of an organism.
• Mutations have beneficial, harmful as well as neutral effects.
• Mutations that lead to changes in genes that further produce unusual protein or changes the function of that protein adversely, are called harmful mutations.
• Albinism in organisms is an example of harmful mutation that fails to produce melanin, a useful pigment that protects organisms against harmful radiation of the sun.
• Hemophilia is a bleeding illness caused by a mutation in the gene that fails to produce blood clotting factor.
• Polyploidy in organisms is a condition of having more than two sets of chromosomes. This leads to the production of extra limbs, two heads, webbed feet, extra fingers etc., in animals and humans.
  Cancer is a leading cause of death worldwide.
• It is caused due to mutations that lead to abnormal growth of cells in the body that grow uncontrollably and form tumors.
• Sickle cell anemia is a disease where the shape of red blood cells is not disc shaped, but sickle shaped, or crescent moon shaped that leads to lower hemoglobin and low blood levels in people.
• Different eye color is observed in human beings due to mutation.
• Polyploidy in plants is an example of neutral mutation, where flowers of same plant show difference in color or show two colors.
• Such types of neutral mutations do not affect the plant and if the owner likes it, he further produces these kinds of plants by grafting and other vegetative propagation methods.