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Mutations - Deletion

A deletion is a mutation resulting in the loss of a segment of the genetic material, and the genetic information contained therein, from the chromosome. The deleted segment may be located in the middle of the chromosome or on the end. A deletion is initiated by breaks in chromosomes induced by such agents as heat, radiation, chemicals, and viruses. The consequences of a deletion depend on the gene or genes that were removed. In this animation, the D region of the chromosome is deleted.

In diploid organisms the effects of a deletion may be minimized by the presence of the other set of genes on the homologous chromosome. Sometimes, however, the deletion of a dominant allele on one homolog can allow harmful recessive alleles on the other homolog to be expressed in the individual as a detectable phenotypic change.


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