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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

ADVANTAGES OF SPECIES BARRIERS? Natural selection can increase reproductive isolation (the Wallace Effect). Allopatric selection from adaptive divergence also leads to an increase in speciation. The production of viable offspring is the key driver in nature. Differences in molecular construction and compatibility can lead to sterility or in viable offspring. Perhaps it is all just an accident of molecular incompatibility, just like sexual organ incompatibility can cause a barrier, rather than a competitive advantage. View in LinkedIn

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QUASI-SPECIES. "An RNA virus population does not consist of a single genotype; rather, it is an ensemble of related sequences, termed quasispecies. Quasispecies arise from rapid genomic evolution powered by the high mutation rate of RNA viral replication." https://lnkd.in/eb_myZ8 View in LinkedIn

SURPRISE FINDING. "The mitochondrial genome specifies a miniscule but essential portion of the mitochondrial proteome, ranging from a low of 3 proteins of defined function in apicomplexans such as Plasmodium to a high of 66 in the excavate Andalucia godoyi, a member of the core jakobids." https://lnkd.in/e8CjRNK View in LinkedIn

BUTTERFLY SPECIES. "Genome analysis suggests that the two species are swapping genes at a surprising rate. But each species has genome segments unique to its own kind, which seem to persist despite the mixing of the rest of the genome. Scientists have dubbed such regions of the genome “islands of speciation.” https://lnkd.in/eKBjZs5 View in LinkedIn

RETAILORING PROCESS. "However, the mitochondrial proteome, most of which is nucleus-encoded, tells another, murkier story. It was expected that many mitochondrial proteins would not have obvious bacterial homologs because they would have emerged specifically within eukaryotes, as part of the endosymbiont-to-organelle retailoring process." https://lnkd.in/e8CjRNK View in LinkedIn

GENOME SEQUENCING. "The results — from studies of crows, butterflies, mosquitoes, fish and other organisms — suggest that the concept of species is even more muddled than we thought, and that genetic changes don’t always align with more visible ones, such as appearance. In some cases, species have big morphological and behavioral changes with only a few genetic changes, and in other cases, there is lots of genetic change with few visible results." https://lnkd.in/eKBjZs5 View in LinkedIn

TAMED AND REWORKED ENDOSYMBIONT. "That the mitochondrial genome is of bacterial (specifically α-proteobacterial) origin is now indisputable." https://lnkd.in/e8CjRNK View in LinkedIn