Elimination of altered karyotypes by sexual reproduction preserves species identity

• Published in: Genome Vol. 50; no. 5; pp. 517 - 524
• Main Author: Heng, Henry H.Q
• Format: Journal Article
• Language: English
• Published: Canada NRC Research Press 01.05.2007; Canadian Science Publishing NRC Research Press
• Subjects: Animal reproduction; Bacteria; Biological Evolution; Cancer; CCAs and NCCAs; CCAs et NCCAs; Cells; Control; diversité génomique; E coli; Genetic aspects; Genetic diversity; Genetic recombination; Genetic Variation; Genome - genetics; genome and species identity; genome diversity; Genomes; identité du génome et de l'espèce; karyotype and cancer evolution; Karyotypes; Karyotyping; Offspring; paradox of sex; paradoxe du sexe; Properties; Recombination, Genetic; Reproduction; reproduction sexuée et asexuée; Selection, Genetic; sexual and asexual reproduction; Sexual reproduction; Species Specificity; Systems stability; évolution du caryotype et du cancer; United States
• ISSN: 0831-2796; 1480-3321
• DOI: 10.1139/G07-039

Resolving the persistence of sexual reproduction despite its overwhelming costs (known as the paradox of sex) is one of the most persistent challenges of evolutionary biology. In thinking about this paradox, the focus has traditionally been on the evolutionary benefits of genetic recombination in generating offspring diversity and purging deleterious mutations. The similarity of pattern between evolution of organisms and evolution among cancer cells suggests that the asexual process generates more diverse genomes owing to less controlled reproduction systems, while sexual reproduction generates more stable genomes because the sexual process can serve as a mechanism to "filter out" aberrations at the chromosome level. Our reinterpretation of data from the literature strongly supports this hypothesis. Thus, the principal consequence of sexual reproduction is the reduction of drastic genetic diversity at the genome or chromosome level, resulting in the preservation of species identity rather than the provision of evolutionary diversity for future environmental challenges. Genetic recombination does contribute to genetic diversity, but it does so secondarily and within the framework of the chromosomally defined genome.