How can autopolyploidy occur?

Autopolyploidy is defined as the condition of having more than two complete sets of chromosomes derived from a single species. This can occur as a result of two main processes: the fertilization of an egg by two sperms, leading to a triploid condition, or through failed chromosome separation during mitosis, which can result in diploid or higher ploidy levels in the daughter cells. When chromosome number is doubled within a single organism without hybridization with another species, it leads to an increased set of chromosomes that all come from the same organism.

The fertilization by two sperms results in an extra set of chromosomes, while mitotic failures, such as nondisjunction, can lead to cells that have multiple copies of the chromosomes, contributing to the overall polyploidy of the organism. Both scenarios allow for the genetic material to be doubled within a single lineage, which is a hallmark of autopolyploidy.