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“DUPLICATION is not the same as life. Complex chemicals are capable of duplication. Amino acids and protein are not alive, but they duplicate and are a requirement for replication. Proto-life catalyzes and carries information required for its own existence.” https://lnkd.in/dSqra5e View in LinkedIn

SO ENDS this second and last weekend on jumping genes. These often autonomous mobile threads of DNA have been important architects of genetic variation across species, liberally sharing genes and making new genes. Like prions, which are just clumps of tangled protein, these chemical threads can proliferate, infect, and move around in the cellular or genomic (respectively) ecosystems that they inhabit. They push our understanding of the boundaries of what it is to be alive towards information that can replicate itself and evolve. View in LinkedIn

DRIVEN BY JUMPING GENES. “It is becoming increasingly difficult to escape the conclusion that eukaryotic genome evolution is driven from within not just by the gentle breeze of the genetic mechanisms that replicate and repair DNA, but by the stronger winds (with perhaps occasional gale-force gusts) of transposon activity. The ability to evoke rapid genome restructuring is at the heart of eukaryotic evolvability—the capacity of organisms with larger and larger genomes to maintain evolutionary flexibility.” http://science.sciencemag.org/content/338/6108/758 View in LinkedIn

INVITATION TO JUMPING GENES. “Thus, responses to stress—whether from pathogens, environmental extremes, or damage to the genetic apparatus—evoke not just a transcriptional response, but also a profound and to some extent heritable change in the epigenetic framework. Such changes can loosen the epigenetic constraints on transposons, allowing stress-inducible TEs to propagate stress-inducible promoters to other genes through transposition.” http://science.sciencemag.org/content/338/6108/758 View in LinkedIn

COBBLED TOGETHER IMPERFECTLY. “Again the Darwinian mantra is that what we see is good enough in its own way, no doubt capable of improvement should the adaptive circumstances demand, but in the grand scheme of things far from perfect. To be honest, a bodge-job, impressive enough, but the rivets showing everywhere.” https://lnkd.in/euEN3Eh View in LinkedIn

IMPACT OF STRESS. “Evidence is accumulating that both biotic and abiotic stresses induce a heritable increase in the ability of plants to withstand infection and tolerate stress. DNA damage, pathogen infection, and abiotic stresses also increase homologous recombination frequency and chromosomal rearrangements, both somatically and heritably.” http://science.sciencemag.org/content/338/6108/758 View in LinkedIn

PHYSICAL LIMITS. “The fact that the limitations that terrestrial extremophiles have reached – be it in terms of temperature, pressure, salinity, pH, or water activity – seem to be close to those capable of carbon-based life forms anywhere.” https://lnkd.in/euEN3Eh View in LinkedIn

“TRANSPOSASES hold a special place in the pantheon of genome sculptors. Arguably the products of the most abundant genes on Earth, transposases are transposon-encoded enzymes that cleave transposon ends and attach them to new sequences.” http://science.sciencemag.org/content/338/6108/758 View in LinkedIn

REACHING BIOLOGICAL LIMITS. “Can we make the case that life has already begun to reach the boundaries of the biological universe (however defined)?” https://lnkd.in/euEN3Eh View in LinkedIn

HOST-PARASITE COLLABORATION. “The traffic in genes and regulatory sequences is bidirectional: Transposons pick up bits and pieces of genes that code for proteins other than transposases, and transposase genes are pressed into services other than transposition.” http://science.sciencemag.org/content/338/6108/758 View in LinkedIn