Autotetraploidyorigin

Autotetraploid origin refers to the origin of autotetraploids, organisms in which the genome comprises four homologous sets of chromosomes all derived from a single species. In such organisms, the four chromosome sets are essentially identical in gene content, though they may diverge over time through mutation and rearrangement.

Autotetraploids can form via genome duplication in a diploid organism (somatic doubling or endoreduplication) or by the fusion of unreduced 2n gametes during self-fertilization or cross-fertilization. Both pathways create a four‑set genome within a single species, enabling the establishment of a stable polyploid lineage under appropriate selective conditions.

Meiosis in autotetraploids often involves the pairing of homologous chromosomes as quadrivalents, which can lead to tetrasomic inheritance and irregular segregation. This chromosomal behavior frequently causes reduced fertility in newly formed autopolyploids. Fertility and meiotic stability can improve over generations through selection and diploidization, a process that reorganizes meiotic behavior toward more regular disomic-like segregation.

Autotetraploidy is common in plants and has played a significant role in speciation, ecological adaptation, and crop improvement. Benefits can include increased cell and organ size, altered gene dosage, and expanded tolerance to environmental stresses. However, initial chromosomal pairing challenges can constrain establishment and reproduction.

Induced autopolyploidy is widely used in plant breeding, typically achieved with chemicals such as colchicine or oryzalin to double chromosome numbers in tissue culture or growing plants. Detection and study of autotetraploids rely on cytogenetics (chromosome counts, karyotyping), flow cytometry for genome size, and molecular markers; genomic sequencing can reveal high homology among the chromosome copies.

Notable examples include cultivated potato (Solanum tuberosum), an autopolyploid important in agriculture.