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FRAGMENT FROM NATURE follows on from the past weekend series on convergent evolution, but this time focuses on reductive evolution, where there is a tendency to simplify. We always assume that complexification is the norm in evolution, and that simpler creatures are less evolved. It is becoming clear that neither assumption is true. View in LinkedIn

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ANIMAL GROWTH ENHANCER. "60% of antibiotic use in nursery-age pigs is for disease prevention or growth promotion. ~60% of antibiotic use in grower/finisher pigs is for growth promotion." HGT in animal guts fosters antibiotic resistance genes." Regulatory agencies have completely betrayed society. https://lnkd.in/eEaXmjy View in LinkedIn

RICH MELTING POT. "Gene transfer is common in the gut. A broad assessment of lateral gene transfer events between bacteria from a multitude of environments showed that human-associated bacteria are 25 times more likely to exchange genetic material than bacteria from other environments, and that closely related human-associated bacteria exhibit horizontal gene transfer (HGT) in 20% to 40% of all pairwise bacterial comparisons." http://www.jci.org/articles/view/72333 View in LinkedIn

GUT MICROBE DENSITY. "The intestinal ecosystem boasts the highest density of microbes of all known environments, with 10(11)–10(12) cells per gram of gastrointestinal content; opportunities for HGT by conjugation are afforded by the intimate proximity of microorganisms." (HGT = Horizontal Gene Transfer). http://www.jci.org/articles/view/72333 View in LinkedIn

WIDESPREAD ANTIBIOTIC RESISTANCE. "A study that described culturable microbes from over 600 individuals revealed that the majority of these individuals harbored gut communities in which at least 10% of members were resistant to a single antibiotic, and over a third carried microbes that exhibited multidrug resistance phenotypes." http://www.jci.org/articles/view/72333 View in LinkedIn

SELECTIVE PRESSURE. "Treatment with antibiotics promotes the transfer of genetic information among bacteria by increasing conjugation, phage transduction, and plasmid mobility, primarily through the activation of cellular stress responses." http://www.jci.org/articles/view/72333 View in LinkedIn

CHRONIC GENE LOSS WITH BURSTS OF GAINS. "The findings that in many if not most lineages evolution is dominated by gene (and more generally, DNA) loss that occurs in a roughly clock-like manner whereas gene gain occurs in bursts associated with the emergence of major new groups of organisms imply a biphasic model of evolution." https://lnkd.in/egqWFZp View in LinkedIn

HUMAN GUT ON ANTIBIOTICS. "Changes to the highly co-evolved microbial community architecture lead to changes in resource availability and species-species interactions, opening niches available for pathogenic intrusion and leading to the loss of colonization resistance. Antibiotics also select for antibiotic-resistant community members, enriching the presence of resistance genes in the microbiome." http://www.jci.org/articles/view/72333 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." https://lnkd.in/egqWFZp View in LinkedIn