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GENE AND INTRON REDUCTION. "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." https://lnkd.in/egqWFZp View in LinkedIn

WE TRANSITION from horizontal gene transfer and attendant problems in the case of antibiotic resistance, or attendant advantages in the case of genetic refreshing, to the great agents of change, namely, viruses and bacteria. These remarkable ancient creatures lived long before the newcomer Homo sapiens, and their evolution streamlined and outsourced their genomes to an advanced simplicity. View in LinkedIn

THIS IS NOT THE PLACE to go into a detailed discussion of GMOs. I have used them to illustrate the practical considerations of horizontal gene transfer, along with antibiotic resistance. Remember the Saxon King Cnut (995-1035) who tested his powers in the East Anglian Wash by commanding the tide not to rise? https://lnkd.in/eMbpfsJ View in LinkedIn

SOIL RESISTANCE POOL. "The reuse of treated wastewater (TWW) for irrigation is a practical solution for overcoming water scarcity, especially in arid and semiarid regions of the world. One such risk stems from the fact that TWW irrigation may increase antibiotic resistance (AR) levels in soil bacteria, potentially contributing to the global propagation of clinical AR." https://lnkd.in/e2B99ZZ View in LinkedIn

SO ENDS this first weekend on reductive evolution. It is becoming clear that evolution has extended periods of gene streamlining and loss interspersed by periods of vigorous gene amplification and innovation as new life forms develop. And among those species who adopt a parasitic or symbiotic lifestyle, there can be massive gene loss. This is contrary to the simple paradigm of life inexorably becoming more complex with time. View in LinkedIn

VIRAL REDUCTIVE EVOLUTION. "The interesting thing about these results is that they indicate that viruses must have diversified from ancient cells by a process called reductive evolution, where organisms simplify instead of becoming more complex." http://www.popsci.com/new-evidence-that-viruses-are-alive View in LinkedIn

MUTATION AND REDUCTION. "There appears to be a negative correlation between mutation rate and genome size among RNA viruses." High is correlated with small. https://lnkd.in/eJEAMe9 View in LinkedIn

RARER DIRECTIONAL EVOLUTION. "Previous analyses of evolutionary patterns, or modes, in fossil lineages have focused overwhelmingly on three simple models: stasis, random walks, and directional evolution. Our expanded survey is consistent with its predecessors in finding that stasis and random walk modes are prevalent in paleontological sequences, and in suggesting that sustained directional evolution is infrequently observed." https://lnkd.in/emAzRkZ View in LinkedIn

REDUCED FUNCTION. "Regardless of the cause of genome reduction, lost coding potential eventually dictates loss of function. Consequences of reductive evolution in streamlined organisms include atypical patterns of prototrophy and the absence of common regulatory systems, which have been linked to difficulty in culturing these cells." https://lnkd.in/ebFkv5a View in LinkedIn

SPECIALIZED LIFESTYLE. "Intracellular bacteria commonly have a reduced genome size, as a consequence of their nutritional dependence on, and adaptation to their host environment and specialization." https://lnkd.in/ebgdSj3 View in LinkedIn