Mutation

A mutation is any change in the genetic structure of a living cell. When that cell divides, the mutation is transmitted to the new cell and in the case of an organism, may result in offspring that look or behave different than its parents. Mutations are random events that can have a variety of causes.

The word mutation is credited to the Dutch botanist Hugo Marie De Vries (1848–1935), who observed random changes that suddenly appeared in the flowers he studied. De Vries named the changes mutations after the Latin word mutare, which means to change. De Vries had independently discovered Mendel's laws of inheritance, and when he added his theory of mutations (which meant there could be sudden "jumps" in evolution) to Mendel's laws, he was able to provide Darwin's theory of evolution with its missing mechanisms of change. We now know that mutations occur constantly in nature and that they are essential to life. Mutations are the source of variation in all living things, and without them populations would never evolve.

Mutations occur at the cellular level. Cells carry their codes for inherited characteristics in threadlike structures called chromosomes which,

in turn, carry genes that consist of a substance called deoxyribonucleic acid, or DNA. The coded information contained in the DNA determines the characteristics of living things. DNA looks like a spiral staircase or ladder, with the stair steps or ladder rungs determining the code for a particular organism. Any change or break in this DNA ladder alters the genetic code and results in a change in the next generation of the organism, whether it is a bacterium or a human being.

[See alsoChromosome; Genetic Disorders; Genetics ]