Evolutionary role of apomixis: S. S. Khokhlov’s hypothesis in the light of modern data
In 1949 S. S. Khokhlov (one of the founders of the Russian scientifi c school on the problem of apomixes) proved the original conception of the progressive evolutionary role of apomixis. He contended that the basic direction of the reproductive system evolution in angiosperms is a gradual failure of...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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Saratov State University
2022-03-01
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| Series: | Известия Саратовского университета. Новая серия: Серия Химия. Биология. Экология |
| Subjects: | |
| Online Access: | https://ichbe.sgu.ru/sites/ichbe.sgu.ru/files/text-pdf/2022/05/himiya_2022_1-89-98.pdf |
| Summary: | In 1949 S. S. Khokhlov (one of the founders of the Russian scientifi c school on the problem of apomixes) proved the original conception of the progressive evolutionary role of apomixis. He contended that the basic direction of the reproductive system evolution in angiosperms is a gradual failure of sex reproduction and transition to apomixis. This hypothesis was heavily criticized and called a “scientist’s fantasy”. In the second half of the 20th century the discovery of recombination repair led to a reassessment of the role of meiosis in the evolution. Now meiosis is considered as the guarantor of genomic stability, and not only as a source of combinative variability. Various molecular-genetic mechanisms of genome transformation unrelated to the sexual process were described. There are gene duplications, horizontal gene transfers and mobile gene systems. All this creates grounds to assume that not only amphymixis but apomixis can solve the dilemma: (1) saving the genotypic structure of the species, (2) providing the genetic diversity of the progeny. Parthenogesis allows the copying of genotypes and the saving of the genotypic structure of the species. The dropping out of meiosis from the development cycle of apomicts, on the one hand, increases its mutability because there is no recombination repair, and, in the other hand, promotes polyploidyzation and consequently contributes to the evolution by gene duplication. The accumulated data about distribution and embryology features of apomicts indicate its signifi cant evolutionary potential. In the light of the modern data S. S. Khokhlov’s hypothesis of the beginning of “apomixis era” appears to be not so fantastic as before. |
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| ISSN: | 1816-9775 2541-8971 |