Offspring can show variations that don't resemble either parent and have never occurred before during past generations of that family. Characteristics like this are referred to as mutations, many of which can be harmful. An organism with a characteristic resulting from mutation is called a mutant. There are two main forms of mutations: gene mutations, which are changes in a single gene so that the traits normally produced are destroyed, and chromosomal mutations, which the entire chromosome is affected. When a cell divides, the genetic information is normally passed on. If a mistake occurs, the DNA molecule will continually replicating therefore the mutation is passed on from generations to come.
Mutagens occur through any known cause but a number of agents are known to increase that rate at which they occur. These are known as mutagenic agents or mutagens. Mutagens are different from other agents in that they don't always cause defects, they manage to increase the rate of mutations taking place. Some known mutagens are mustard gas, formaldehyde, sulfur dioxide, and some antibiotics.
Mutations can occur in the body cells or in the reproductive cells of a person. The first case, where the body cells, or somatic cells, are involved is known as a somatic mutation. If the reproductive cells are affected the mutation can occur in the gametes and may then be passed on to the next and subsequent generations. These are known as germ-line mutations. In this case the individual in whom the mutation occurs is not usually affected.
Mutagens occur through any known cause but a number of agents are known to increase that rate at which they occur. These are known as mutagenic agents or mutagens. Mutagens are different from other agents in that they don't always cause defects, they manage to increase the rate of mutations taking place. Some known mutagens are mustard gas, formaldehyde, sulfur dioxide, and some antibiotics.
Mutations can occur in the body cells or in the reproductive cells of a person. The first case, where the body cells, or somatic cells, are involved is known as a somatic mutation. If the reproductive cells are affected the mutation can occur in the gametes and may then be passed on to the next and subsequent generations. These are known as germ-line mutations. In this case the individual in whom the mutation occurs is not usually affected.