Hi,
The word mutation come from word mutate, that means to change. In Biology, a mutations means a change in the DNA sequence of an organism. Since DNA sequence encodes for proteins, when a mutation occurs in part of DNA (gene) it causes a different than usual protein which had to be expressed.
For example:
- There was a gene whose sequence was: AATGGGGCCC
- A single base mutation made the sequence as: TATGGGGCCC
Now how these mutations affect an organism in which they took place?
The answer is, mutations can be beneficial, harmful and even neutral.
A mutations is beneficial when the sequence changes in such a way that the new protein gives beneficial characteristics to the organism. For instance, a mutation occurs in the DNA of bacteria which enhances its resistance against antibiotics, so the bacteria can live longer. This is a beneficial mutation for bacteria. Sometimes, the mutations can be lethal and very hamrful. For instance, when a mutation occurs in the coding region of a gene for certain trait of organism like skin type, skin color. If mutation happens in coding region of skin type, in such a way that new protein formed is not correct, it can heavily harm. Like a mutation changes the skin color of people living in hot areas from from dark to pale color. The pale color is prone to more damage than dark color, therefore, these skins are easily burnt and can causes skin cancer and other skins problems to people. Similarly, some mutations can be neutral and they cause neither benefit, nor harm, no effect on organism. These are called silent mutations because the DNA sequence is changed in such a way that new protein is same as old protein. For example there is a gene having part CCG, after mutation it changes to CCA. Both will code for the same protein Glycine and will have no effect on overall phenotype of organism.
Hope it help!
