what is deletion chromosome
Deletion on a chromosome. In genetics, a deletion (also called gene deletion, deficiency, or deletion mutation) (sign: Î´) is a mutation (a genetic aberration) in which a part of a chromosome or a sequence of DNA is lost during DNA replication.Any number of nucleotides can be deleted, from a single base to an entire piece of chromosome. ' Terminal Deletion' â a deletion that occurs towards the end of a chromosome. 2  Intercalary Deletion / Interstitial Deletion â a deletion that occurs from the interior of a chromosome. 3  Microdeletion â a relatively small amount of deletion (up to 5Mb that could include a dozen genes).