Autopolyploïdy

Autopolyploidy is a type of polyploidy where an individual has more than two sets of chromosomes, and all of these sets are derived from the same species. This occurs when the normal process of meiosis, which reduces the chromosome number by half, fails. This failure can happen at different stages of meiosis or mitosis, leading to gametes or somatic cells with a duplicated chromosome number. For example, if a diploid organism with 2n chromosomes undergoes a meiotic error, it might produce diploid gametes (2n) instead of haploid gametes (n). If these diploid gametes fuse, the resulting zygote will be tetraploid (4n). Autopolyploidy can also arise from mitotic errors. An organism with an autopolyploid state is called an autopolyploid. These individuals typically exhibit increased vigor and size, a phenomenon known as gigas effect, and can have larger flowers, fruits, and seeds. Autopolyploidy is relatively common in plants, contributing to evolutionary diversification and the development of new crop varieties. Examples include some species of alfalfa, wheat, and potatoes. In animals, autopolyploidy is much rarer due to the complexities of sex determination and development.