*** Welcome to piglix ***

Endogenosymbiosis


Endogenosymbiosis is an evolutionary process, proposed by the evolutionary and environmental biologist Roberto Cazzolla Gatti, in which "gene carriers" (viruses, retroviruses and bacteriophages) share parts of their genomes in an endogenous symbiotic relationship with their hosts.

The related process of symbiogenesis or endosymbiosis was proposed by Lynn Margulis in 1967. She argued that the internal symbiosis of bacteria-like organisms had formed organelles like chloroplasts and . She proposed that this had created the eukaryotes, and thus driven the expansion of life on Earth. She had argued that this process of symbiotic collaboration had run alongside the classical Darwinian cycle of mutation, natural selection and adaptation.

Roberto Cazzolla Gatti, Ph.D., associate professor at Tomsk State University (Russia), argued in his hypothesis that "the main likely cause of the evolution of sexual reproduction, the parasitism, also represents the origin of biodiversity". In other terms, this theory suggests that sexual reproduction acts as a conservative system against the inclusion of new genetic variations into cells' DNA (supported by the DNA repair systems) and, instead, the evolution of species can take place only when this preservative system fails to contrast the inclusion, within the host genome, of hexogen parts of DNA (and RNA) coming from obliged "parasitic" elements (viruses and phages) that establish a symbiosis with their hosts. "As two parallel evolutionary lines – Cazzolla Gatti wrote in his original paper – sexual reproduction seems to preserve what the endogenosymbiosis moves to diversify. Following the former process, the species can adapt slowly and indefinitely to the external factors, adjusting themselves, but not 'creating' novelty. The latter process, instead, leads to the speciation due to sudden changes in genes sequences. Not only organelles can be symbiotic with other cells, as suggested Lynn Margulis, but entire pieces of genetic material coming from symbiotic parasites, can be included in the host DNA, changing the gene expression and addressing the speciation process".


...
Wikipedia

...