Editing Genetic variation (section)

== Sources ==
[[File:Coquina variation3.jpg|thumb|upright|A range of variability in the mussel ''Donax variabilis'']]

Random [[mutation]]s are the ultimate source of genetic variation. Mutations are likely to be rare, and most mutations are neutral or deleterious, but in some instances, the new alleles can be favored by natural selection.  [[Polyploidy]] is an example of chromosomal mutation. Polyploidy is a condition wherein organisms have three or more sets of genetic variation (3n or more).

Crossing over ([[genetic recombination]]) and random segregation during [[meiosis]] can result in the production of new [[allele]]s or new combinations of alleles. Furthermore, random fertilization also contributes to variation. Variation and recombination can be facilitated by [[transposable elements|transposable genetic elements]], [[endogenous retrovirus]]es, LINEs, SINEs, etc.{{cn|date=December 2021}} For a given genome of a multicellular organism, genetic variation may be acquired in somatic cells or inherited through the germline.