endosymbiont

Examples of endosymbiont in the following topics:

• The Evolution of Plastids

  • There is also, as with the case of mitochondria, strong evidence that many of the genes of the endosymbiont transferred to the nucleus.
  • This leads to the question of the possibility of a cell containing an endosymbiont to become engulfed itself, resulting in a secondary endosymbiosis .
  • Some of the major groups of algae became photosynthetic by secondary endosymbiosis; that is, by taking in either green algae or red algae as endosymbionts.
  • The chloroplasts contained within the green algal endosymbionts are capable of photosynthesis, making chlorarachniophytes photosynthetic.
  • The green algal endosymbiont also exhibits a stunted vestigial nucleus.

• Endosymbiosis and the Evolution of Eukaryotes

  • Christian de Duve proposed that they may have been the first endosymbionts, allowing cells to withstand growing amounts of free molecular oxygen in the earth's atmosphere.
  • It is believed that over millennia these endosymbionts transferred some of their own DNA to the host cell's nucleus during the evolutionary transition from a symbiotic community to an instituted eukaryotic cell (called "serial endosymbiosis").
  • The cyanobacterial endosymbiont already had a double membrane.

• Genome Evolution

  • Another beautiful example are endosymbiont species.
  • For instance, Polynucleobacter necessarius was first described as a cytoplasmic endosymbiont of the ciliate Euplotes aediculatus.
  • The latter species dies soon after being cured of the endosymbiont.
  • The endosymbionts have a significantly reduced genome when compared to their free-living relatives (1.56 Mbp vs. 2.16 Mbp).

• Endosymbiotic Theory and the Evolution of Eukaryotes

  • This occurs when one species is taken inside the cytoplasm of another species, which ultimately results in a genome consisting of genes from both the endosymbiont and the host.
  • This mechanism is an aspect of the Endosymbiont Theory, which is accepted by a majority of biologists as the mechanism whereby eukaryotic cells obtained their mitochondria and chloroplasts.
  • The double membrane would be a direct result of endosymbiosis, with the endosymbiont picking up the second membrane from the host as it was internalized.

• The Evolution of Mitochondria

  • This has been interpreted as evidence that genes have been transferred from the endosymbiont chromosome to the host genome.
  • This loss of genes by the endosymbiont is probably one explanation why mitochondria cannot live without a host.

• Mitochondria

  • These prokaryotic cells may have been engulfed by a eukaryote and became endosymbionts living inside the eukaryote.

• Genomic Similiarities between Distant Species

  • The majority of evolutionary models, such as in the endosymbiont theory, propose that eukaryotes descended from multiple prokaryotes, which makes HGT all the more important to understanding the phylogenetic relationships of all extant and extinct species.

• Phylum Porifera

  • Other species host photosynthesizing micro-organisms as endosymbionts; these alliances often produce more food and oxygen than they consume.