A sudden change in the amount, arrangement or structure of the DNA or chromosomes of an organism is called mutation. The mutation alters the hereditary material of an organism’s cell and may or may not be inherited by cells. A mutation may result in a change in the appearance of a characteristic in a population.
Mutations occurring in gamete cells are inherited while those occurring in somatic cells (called somatic mutations) are usually not inherited.
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A mutation resulting from a change in the amount or arrangement of DNA is known as chromosomal mutation.
A mutation resulting from a change in the structure of gene in DNA is known as gene mutation.
Causes of Mutation:
Mutation can be caused by a variety of chemical substances such as mustard gas, caffeine, gamma rays and X-rays and sometimes even certain pesticides.
Sickle cell anemia is an example of disease caused due to mutation. It is a blood disorder characterized by red blood cells that assume an abnormal rigid, sickle shape due to sudden change in DNA structure.
Genetic Engineering:
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A technique in which the genetic constitution of an organism can be altered by introducing new genes or replacing existing genes into its chromosomes is known as genetic engineering. For example, insulin producing genes are introduced in a bacteria to produce insulin.
Genetic Counselling:
This is a counselling of the parents/newly married couples in which they are advised to get them screened for any genetic diseases such as haemophilia, thalassemia, down’s syndrome, etc.