Category: Uncategorized

FIRST LIFE FORMS. "The quasispecies concept originated in a theoretical formulation of molecular evolution that emphasized error-prone replication of simple RNA or RNA-like replicons as an essential feature of self-organization and adaptability of primitive life forms." http://www.sciencedirect.com/science/article/pii/S0042682215001580 View in LinkedIn

QUASISPECIES. "Two main aspects are addressed: (i) mutant clouds as reservoirs of phenotypic variants for virus adaptability and (ii) the internal interactions that are established within mutant spectra that render a virus ensemble the unit of selection." http://mmbr.asm.org/content/76/2/159.short View in LinkedIn

MUTANT SWARMS. "Evolution of RNA viruses occurs through disequilibria of collections of closely related mutant spectra or mutant clouds termed viral quasispecies." https://lnkd.in/d9Upsp3 View in LinkedIn

"VIRAL QUASISPECIES are the mutant distributions (also termed mutant swarms or mutant clouds) that are generated upon replication of RNA viruses, and some DNA viruses in infected cells and organisms." http://www.sciencedirect.com/science/article/pii/S0042682215001580 View in LinkedIn

GROUP SELECTION. "Two types of interactions have been evidenced: negative interactions (also termed interfering interactions) by which some genomes affect negatively the replication of other genomes of the same ensemble, and positive interactions (akin to classical complementation) by which genomes reinforce each other to achieve a higher replication rate. The result of these interactions is that evolution operates at the level of the population, a process often called ‘group selection”." http://www.sciencedirect.com/science/article/pii/S0042682215001580 View in LinkedIn

DEFINITIONAL CONVENIENCE? "There are lots of other places where the boundary of a species is blurred. It's not so surprising that these blurry places exist — after all, the idea of a species is something that we humans invented for our own convenience!" http://evolution.berkeley.edu/evolibrary/article/evo_41 View in LinkedIn

SINGLE ENTITY MUTANT SWARMS. "A realization of recent years is that mutant swarms are not mere collections of mutants ranked by a mutation-selection balance that act independently of each other. Rather, very often the mutant ensemble acts as a unit of selection due to interactions among its members." https://lnkd.in/dJdEQAk View in LinkedIn

"A SPECIES is often defined as a group of individuals that actually or potentially interbreed in nature. In this sense, a species is the biggest gene pool possible under natural conditions. The definition of a species as a group of interbreeding individuals cannot be easily applied to organisms that reproduce only or mainly asexually. Also, many plants, and some animals, form hybrids in nature. Should they be considered the same species or separate species?" https://lnkd.in/e3Bgi6R View in LinkedIn

NEGATIVE SELECTION. "Mutant swarm generation might be prevented only if negative (or purifying) selection eliminated the great majority of newly arising mutant genomes, which is not the case. Current evidence suggests that a considerable proportion of mutants might be eliminated by negative selection, but it is not clear whether all mutations considered lethal by standard measurements of viral production might not be in reality low fitness variants that can populate low frequency levels of mutant spectra, either because they can replicate minimally or because they are helped by complementation." http://www.sciencedirect.com/science/article/pii/S0042682215001580 View in LinkedIn

FRAGMENT FROM NATURE: this meditation considers viral hybrid swarms and quasispecies, which cloud traditional thinking about species. As usual, viral entities thumb their noses at biological norms, and on the topic of species, it is a spectacular thumbing. Viruses challenge biologists to rethink many old assumptions. View in LinkedIn