Mutations are sudden changes in genotype, involving qualitative and quantitative alterations in the genetic material itself which change the phenotype of an organism. Hugo de Vries (1901) was the first scientist who used the term mutation to describe the heritable phenotypic changes of the evening primrose Oenothera lamarckiana. Many mutations described by de Vries in O. lamarckiana are due to variation in chromosome number and chromosomal aberrations. Mutants of Oenothera were so different from the parent plant that it was not difficult to call these as new species. These mutants were pure breeding. According to de Vries mutations are basis of evolution.
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Main features of mutation
The main feature of mutations are as follows :—
1. Mutations may occur at any stage in the development of organism.
2. Mutations may take place either in somatic cells or in the germinal tissue.
3. Mutations may arise spontaneously in nature or may be induced artificially.
4. Mutations may be harmful or useful,
5. Mutations occur in all living organisms
6. They are rare
7. Mutations may be large or small
8. They may effect the structure and functioning of an organism.
9. Mutations are usually recessive and very few mutations are dominant.
10. They are usually lethal in their action but may be beneficial or at least not harmful.