Natural genetic engineering: A programmed chromosome/DNA elimination.

Typically, all cells of a given organism have the same set of chromosomes. However, there are exceptions to this rule, and in many organisms, the somatic cells and germ cells, various types of somatic cells or organs, or females and males, have different genomes. One of the sources of such differences is chromosome/DNA elimination/chromatin diminution that is a naturally programmed phenomenon. We describe chromosome/DNA elimination in various organisms and present the current hypotheses on its origin, mechanisms, significance, and consequences. [Display omitted] • Chromosome/DNA elimination occurs in unicellular and multicellular organisms. • Chromosome/DNA elimination creates the difference between germline and soma. • Sex chromosome elimination creates the difference between sexes. • Chromosome/DNA elimination mechanisms differ between organisms. • Chromosome/DNA elimination is an evolutionarily very ancient phenomenon. [ABSTRACT FROM AUTHOR]