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NOVEL DEFINITION. “The history of life is a story of parasite-host coevolution that includes both the incessant arms race and various forms of cooperation. All organisms are communities of interacting, coevolving replicators of different classes.” https://www.sciencedirect.com/science/article/pii/S1369848616300103 View in LinkedIn

SELFISHNESS. “The status of viruses among biological entities is readily defined within the replicator paradigm. All biological replicators form a continuum along the selfishness-cooperativity axis, from the completely selfish to fully cooperative forms.” https://www.sciencedirect.com/science/article/pii/S1369848616300103 View in LinkedIn

SPECTRUM OF REPLICATORS. “Viruses are ubiquitous, major biological entities. Viruses fit with the continuum of replicators from selfish to cooperative. Selfish elements are intrinsic to any evolving system of replicators.The entire history of life is a story of parasite-host coevolution.” https://www.sciencedirect.com/science/article/pii/S1369848616300103 View in LinkedIn

SAD AND COMMON POSITION. “The question whether or not “viruses are alive” is not a scientific question.” https://www.sciencedirect.com/science/article/pii/S1369848616300103 View in LinkedIn

FRAGMENT FROM NATURE contemplates for this and next weekend, jumping genes (more correctly, transposons or mobile genetic elements) that are generated by viruses. These semi-autonomous simple strands of DNA including genes defy our ideas of life. Just strings of chemicals, they hop around host genome ecosystems as free-living parasites and symbionts, and also have had an enormous impact on evolution across taxa. These curious entities are truly extraordinary, and we still know so little about them. View in LinkedIn

THIS IS THE END of this long section on the biology of death. The subject is far from over, and the transition is purely artificial. I hope that this series of perspectives from a biological viewpoint, nested in observations and experiments across the living world has been insightful. View in LinkedIn

DNA REPEATS. “Interspersed repeats within genomes are created by transposition events accumulating over evolutionary time. Because interspersed repeats block gene conversion, they protect novel gene sequences from being overwritten by similar gene sequences and thereby facilitate the development of new genes. TEs may also have been co-opted by the vertebrate immune system as a means of producing antibody diversity. The V(D)J recombination system operates by a mechanism similar to that of some TEs.” (TE = transposable elements, jumping genes). https://en.m.wikipedia.org/wiki/Transposable_element View in LinkedIn

DEATH ANTAGONISTS. "Peter Thiel, the billionaire co-founder of PayPal, plans to live to be 120. Compared with some other tech billionaires, he doesn’t seem particularly ambitious. Dmitry Itskov, the “godfather” of the Russian Internet, says his goal is to live to 10,000; Larry Ellison, co-founder of Oracle, finds the notion of accepting mortality “incomprehensible,” and Sergey Brin, co-founder of Google, hopes to someday “cure death.” http://www.newsweek.com/2015/03/13/silicon-valley-trying-make-humans-immortal-and-finding-some-success-311402.html View in LinkedIn

JUMPING GENE FOSSILS. “Evolution often deactivates DNA transposons, leaving them as introns (inactive gene sequences). In vertebrate animal cells, nearly all 100,000+ DNA transposons per genome have genes that encode inactive transposase polypeptides. In humans, all Tc1-like transposons are inactive.” https://en.m.wikipedia.org/wiki/Transposable_element View in LinkedIn

BIRTH AND DEATH. “Beginnings are often difficult to pinpoint, particularly in life cycles, for life is continuous. Life does not tolerate a break (at most a transitory standstill in a stage of quiescence). Life is a continuing process that started some billions of years ago below the level of multicellularity and will end with the death of the last living being. Nevertheless, each individual life that is based on sexual reproduction has two discrete boundaries: fertilization and death.” https://lnkd.in/d6G9geU View in LinkedIn