What are four types of chromosomal mutations?

Deletion, duplication, inversion and translocation are the four types of chromosomal mutation.

Deletion, duplication, inversion and translocation are the four types of chromosomal mutation. If a significant amount of genetic information is lost, the mutation is likely lethal.

Deletion is when genetic material on the is lost. A few could be lost or a larger number are lost. Deletions can happen anywhere on the chromosome. In the image above, B has been lost.

Duplication occurs when a portion of the chromosome is copied and replicated, so that there is extra information. In the image above, B has been duplicated.

In inversion, the order of some of the genetic material is reversed or switched. A segment of the chromosome is reversed. No genetic information is lost, but if the break and reversal occurs at a crucial point, then there can be serious consequences and the inversion could be lethal. In the image above, if A needs to be adjacent to B for the organism to survive, the inversion would be lethal.

Translocation occurs when a piece of one chromosome breaks off and is transferred to a new location on another chromosome. In the image above, the chromosome that originally began with ABC has lost DEF and gained JKL. DEF has been translated to the second chromosome so that it now reads GHIDEF. Down's syndrome is an example of a translocation mutation. A piece of chromosome 21 breaks off and attaches to chromosome 14.