Autodiploids

Autodiploids are organisms that possess two sets of chromosomes, both of which are derived from the same ancestral species. This means that the organism's genome consists of two identical or very similar sets of chromosomes. Autodiploidy is a form of polyploidy, where an organism has more than two complete sets of chromosomes. In contrast to allotetraploids, which arise from the hybridization of two different species followed by chromosome doubling, autodiploids have chromosome sets originating from a single parent species.

The formation of autodiploids can occur spontaneously through errors during meiosis, the cell division process that produces gametes. If the chromosomes fail to separate properly during meiosis, a diploid gamete can be produced. When this diploid gamete fuses with a normal haploid gamete, or if it self-fertilizes, an autodiploid organism is formed. Another mechanism is through errors in mitosis in somatic cells, leading to polyploid tissues within an otherwise diploid organism.

Autodiploids often exhibit a phenomenon known as "dosage effect," where the presence of two copies of each gene can lead to increased gene expression and potentially altered phenotypes compared to their diploid ancestors. This can result in larger cell size, increased vigor, or changes in biochemical pathways. While autodiploidy is relatively common in plants and some fungi, it is less frequent in animals. In plants, autodiploidy has been exploited in agriculture to create varieties with desirable traits.