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KARL SIMS WAS THE FIRST big name in "evolved viral life" or "artificial life". Inspired by his work, many others explored this space, including some who made significant contributions. https://lnkd.in/dh-4NJm View in LinkedIn

VARIANT SIMILARITY. “Despite their differences, all genetic systems share one significant bias: the vast majority of changes to the code we presently know of involve termination or stop codons being reassigned to encode an amino acid.” https://lnkd.in/d87ZWbH View in LinkedIn

IGNORE TIME. "Why wait another billion years for genome improvement, when you can take evolution into your own hands?" (Karl Sims). https://lnkd.in/dD4T763 View in LinkedIn

MORE VARIANT CASES. “In nuclear genomes, variants are also rare, but as protist genome diversity is explored the number of cases is expanding. One interesting pattern to emerge is that the frequency of different kinds of changes in nuclear genomes is different from those of mitochondria and bacteria (the most obvious being the prevalence of UAR=Q versus UGA=W, respectively). Once again, this likely reflects a fundamental difference in their genomes, in this case the underlying translation systems (amino acyl tRNA syntheses and termination factors).” https://lnkd.in/d87ZWbH View in LinkedIn

SO ENDS this two weekend contemplation on the genetic code. Once again, the influence of microbial horizontal gene transfer has contributed to the conservation of the genetic code in unrelated living cells. It seems very likely other variant codes will be discovered. Whether there are creatures that can reproduce with hugely different genetic structures awaits to be seen, but is very relevant to the search for new life both on earth, and elsewhere. View in LinkedIn

NEW CELLULAR DNA. “Australian researchers have identified a new DNA structure -- called the i-motif -- inside cells. A twisted 'knot' of DNA, the i-motif has never before been directly seen inside living cells. The new shape looks entirely different to the double-stranded DNA double helix. We think the coming and going of the i-motifs is a clue to what they do. It seems likely that they are there to help switch genes on or off, and to affect whether a gene is actively read or not." https://lnkd.in/dC4Eqkg View in LinkedIn

CONSERVING FORCES. “Conceivably, frozen accident and the requirement of horizontal gene transfer were major, complementary factors that have kept the code universal.” https://lnkd.in/dKTqJpY View in LinkedIn

HORIZONTAL EXPLANATION. “Then, why only one frozen accident, assuming that the actual codon assignments are indeed (quasi) accidental? To put it even more generally, why a single last universal common ancestor only? Only one code survived because extensive horizontal gene transfer was an aspect of early evolution without which the transition to the cellular level of complexity would not have been possible. Even a small change in the code has a prohibitive effect on horizontal gene transfer.” https://lnkd.in/dKTqJpY View in LinkedIn

ARTIFICIAL CODE. “New methods of synthetic biology have recently allowed substantial artificial alteration of the code in bacteria. Although the fitness of the bacteria with altered codes has not been thoroughly studied, their viability itself seems to support the view that the fitness of different codes might not differ dramatically, so that the (near) universality of the standard genetic code is likely to stem from high fitness barriers separating it from other codes, or in other words, low fitness of the intermediates.” https://lnkd.in/dKTqJpY View in LinkedIn

PARADIGM WRECKERS. “Further study of how translation functions in Blastocrithidia will cast a unique light on how the code works, which will certainly be challenging since it is not only an uncultured symbiont, but also a trypanosome, a lineage which is notorious for re-writing the rule books of molecular biology and genomics.” https://lnkd.in/d87ZWbH View in LinkedIn