Allopolyploidie

Allopolyploidie is a type of polyploidy where an organism inherits extra sets of chromosomes from two or more different species. This contrasts with autopolyploidy, where additional chromosome sets originate from the same species. Allopolyploidy arises from hybridization between two distinct species, followed by a doubling of the chromosome number. This doubling is crucial as it restores fertility to the hybrid, which would otherwise be sterile due to mismatched chromosome sets. The resulting allopolyploid organism contains complete sets of chromosomes from each parent species.

This phenomenon is a significant evolutionary mechanism, particularly in plants. It can lead to the rapid formation of new species with novel characteristics, as the combination of genetic material from different lineages can result in advantageous traits. For example, many important crop plants, such as wheat, cotton, and tobacco, are allopolyploids. The increased genetic diversity within an allopolyploid can confer greater adaptability to different environments and resistance to diseases. The process often involves the formation of a sterile hybrid, followed by spontaneous or induced chromosome doubling, which creates homologous chromosomes from each parent, allowing for proper meiosis and the production of viable gametes. Allopolyploidy is a testament to the creative power of hybridization and chromosome duplication in shaping biodiversity.