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NUCLEAR HEADQUARTERS. "Reflecting its symbiotic origin, most of the proto-mitochondrion bacterial genome was transferred to the eukaryotic chromosomes so that it now encodes only a small subset of proteins and RNAs necessary for mitochondrial biogenesis. The vast majority of the mitochondrial proteome (~ 1500 proteins) are nuclear-encoded and require translocation into the mitochondrion through specific mechanisms." https://lnkd.in/e533NK2 View in LinkedIn

BACTERIAL ROLE IN GREAT LEAP FORWARD. "Although the evolutionary details of the prokaryote-to-eukaryote transition are still incompletely resolved, the crucial role that mitochondria played in that transition is becoming increasingly evident." The mitochondrion was of ancient bacterial origin. http://gbe.oxfordjournals.org/content/4/4/466.full View in LinkedIn

BACTERIAL DADDY. "The data underscore the archaebacterial (host) nature of the eukaryotic informational genes and the eubacterial (mitochondrial) nature of eukaryotic energy metabolism." Darwin would have it that we descended from the ape. Rather, we have older bacterial and viral parents. http://gbe.oxfordjournals.org/content/4/4/466.full View in LinkedIn

MOSTLY SINGLE ORIGIN. "We identified and investigated 712 eukaryotic protein families that have prokaryotic homologues. Of those trees, 571 (80%) reflect a single origin for the eukaryotic gene. For the remaining 141 genes whose trees do not directly reflect a single origin, there are causes other than LGT from prokaryotes to eukaryotes that can readily account for the lack of observed eukaryote monophyly." (LGT = Lateral Gene Transfer or horizontal gene transfer). https://lnkd.in/eqauQJt View in LinkedIn

LARGE DATA REVIEW. "To test the predictions of competing and mutually exclusive hypotheses for the origin of eukaryotes, we identified from a sample of 27 sequenced eukaryotic and 994 sequenced prokaryotic genomes 571 genes that were present in the eukaryote common ancestor and that have homologues among eubacterial and archaebacterial genomes." https://lnkd.in/eqauQJt View in LinkedIn

THE NUCLEUS WAS A VIRUS. "The current interpretation is that the precursor of the eukaryotic nucleus was indeed a huge membrane-covered DNA virus that persistently colonized a prokaryotic host." Add to that fact that the mitochondria (animal energy cell) was a bacteria, as was the plant chloroplast (the plant powerhouse). All the top cellular jobs taken by our friends the microbes. https://lnkd.in/e-pJFM6 View in LinkedIn

BURST IN GENE DUPLICATION AND NOVELTY appears to have been one of the complexification steps in the emergence of new life forms, interrupting longer periods of genetic simplification. These events are poorly understood, to say the least. View in LinkedIn

"THE TRANSITION from prokaryotes to eukaryotes was the most radical change in cell organisation since life began, with the largest ever burst of gene duplication and novelty. This radical transformation of cell structure (eukaryogenesis) is the most complex and extensive case of quantum evolution in the history of life." https://lnkd.in/enZ4-ZD View in LinkedIn

NUCLEATED CELLS. "Eukaryote cells are all evolutionary chimaeras of an ancestrally phagotrophic host cell with nucleus, endomembranes, and endoskeleton and an enslaved α-proteobacterium converted into a mitochondrion close to the time when the nucleus itself originated." https://lnkd.in/enZ4-ZD View in LinkedIn

SO ENDS Part One on the issue of speciation. Hybridization between species, quasi-species and horizontal gene transfer illustrate that tidy species barriers leading to reproductive isolation can be breached. Darwin's view of the evolutionary drive to species formation has dominated biology until recently. Now, it appears that perhaps enriching the global gene pool by any mechanism may be a stronger driver. View in LinkedIn