Year: 2022

MASSIVE GENE LOSS. "Two notable examples are the reconstruction of the complex archaeal ancestor and the intron-rich ancestor of eukaryotes. In both cases, evolution in most of the lineages was apparently dominated by extensive loss of genes and introns, respectively." http://onlinelibrary.wiley.com/doi/10.1002/bies.201300037/full View in LinkedIn

GENOMIC STREAMLINING. "Genomic researchers have proposed that natural selection may favor small genomes—weeding out superfluous material—through a process called “genomic streamlining. Streamlining makes inherent sense because a small genome should aid metabolic efficiency, because genome size is correlated with cell size." http://scholar.google.es/scholar?q=selective+pressures+for+genomic+simplicity&hl=en&as_sdt=0&as_vis=1&oi=scholart&sa=X&ved=0ahUKEwi8_67jh8zPAhXBbRQKHa6-BbEQgQMICDAA View in LinkedIn

TWO PHASES OF EVOLUTION. "These and many other cases of reductive evolution are consistent with a general model composed of two distinct evolutionary phases: the short, explosive, innovation phase that leads to an abrupt increase in genome complexity, followed by a much longer reductive phase, which encompasses either a neutral ratchet of genetic material loss or adaptive genome streamlining." http://onlinelibrary.wiley.com/doi/10.1002/bies.201300037/full View in LinkedIn

EPISODIC AMPLIFICATION. "Quantitatively, the evolution of genomes appears to be dominated by reduction and simplification, punctuated by episodes of complexification." http://onlinelibrary.wiley.com/doi/10.1002/bies.201300037/full View in LinkedIn

DRUNKARD'S WALK. "Gould argued that the average complexity of life forms has barely increased over the course of the history of life, even as the upper bound of complexity was being pushed upwards, perhaps for purely stochastic reasons, under a “drunkard's walk” model of evolution." http://onlinelibrary.wiley.com/doi/10.1002/bies.201300037/full View in LinkedIn

PARASITIC SIMPLIFICATION. "It has been well known for decades that the evolution of numerous parasitic and symbiotic organisms entails simplification rather than complexification. In particular, bacteria that evolve from free-living forms to obligate intracellular parasites can lose up to 95% of their gene repertoires without compromising the ancestral set of highly conserved genes involved in core cellular functions." http://onlinelibrary.wiley.com/doi/10.1002/bies.201300037/full View in LinkedIn

“GENETIC OUTSOURCING is not to be confused with simplification in parasite downsizing. In many cases, access to the host genome, or simply parking of its own genetic burden can be seen as a type of genetic expansion strategy. Streamlining with greater efficiency and greater plasticitymay be a better term than simplification.” http://onlinelibrary.wiley.com/doi/10.1002/bies.201300037/full View in LinkedIn

EXEMPLARS OF STREAMLINING. "The mitochondria, the ubiquitous energy-transforming organelles of eukaryotes, and the chloroplasts, the organelles responsible for the eukaryotic photosynthesis, are the ultimate realizations of bacterial reductive evolution." http://onlinelibrary.wiley.com/doi/10.1002/bies.201300037/full View in LinkedIn

DUBIOUS EQUIVALENT. "The utility of equating complexity with entropy is dubious at best as becomes particularly clear when one attempts to define genomic complexity. Indeed, using sequence entropy (Shannon information) as a measure of genomic complexity is obviously disingenuous given that under this approach the most complex sequence is a truly random one that, almost by definition is devoid of any biological information." http://onlinelibrary.wiley.com/doi/10.1002/bies.201300037/full View in LinkedIn

NOT A SIMPLE CORRELATION. "The relationship between genomic complexity and the complexity at various levels of the phenotype, from molecular to organismal, is far from being straightforward as it has become clear already in the pre-genomic era." Some relatively simple creatures have much greater genomic complexity than more complex creatures. http://onlinelibrary.wiley.com/doi/10.1002/bies.201300037/full View in LinkedIn