- Loss of a segment of DNA from a chromosome (and hence from the genome). The first human chromosome deletion was detected in 1963 by Jerome Lejeune and his colleagues in Paris. They discovered loss of part of 5p, the short (p) arm of chromosome 5, in children with a hitherto-undescribed condition with mental retardation and multiple congenital anomalies (birth defects) they named the cri du chat (cat-cry) syndrome. A chromosome deletion is the opposite of a chromosomal duplication.
* * *In genetics, any spontaneous elimination of part of the normal genetic complement, whether cytogenetically visible (chromosomal d.) or found by molecular techniques. [L. deletio, destruction]- gene d. d. of a segment of a chromosome too small to be detected cytogenetically, inferred from the phenotype at one particular locus.- nucleotide d. d. of a single nucleotide, which in a transcribed gene will lead to a frame-shift mutation. SYN: point d. (2).- point d. 1. d. involving a submicroscopic loss of genetic material too small to be resolved by linkage analysis; 2. SYN: nucleotide d..
* * *de·le·tion di-'lē-shən n1) the absence of a section of genetic material from a gene or chromosome2) the mutational process that results in a deletion
* * *n.(in genetics) a type of mutation involving the loss of DNA. The deletion may be small, affecting only a portion of a single gene, or large, resulting in loss of a part of a chromosome and affecting many genes.
* * *de·le·tion (del) (də-leґshən) [L. deletio destruction] in genetics, the loss of any portion of the genetic material on a chromosome, ranging from loss of a single nucleotide within, which can throw the reading frame out of register and cause a frameshift mutation if it is within a coding sequence, to loss of part or all of a gene, to loss of a microscopically visible portion of the chromosome, possibly involving multiple genes.
Medical dictionary. 2011.