Tag: images

Eukaryogenesis

Genetic analysis places Loki squarely within the single-celled archaea. But it possesses an intriguing collection of genes that look as though they would be more at home in eukaryotes, rather like modern words dotting a medieval manuscript. In fact, Loki’s genetic machinery suggests that the organism might be able to engulf other cells, the first step in the creation of mitochondria. Even if Loki doesn’t solve the mystery of our ancient origins, its discovery shows just how much biological diversity remains to be unearthed. Perhaps the next discovery will be a eukaryote with no history of possessing mitochondria. Or perhaps it will be an archaeon with signs of a symbiotic bacterium living within.

2020-11-25: Viral nucleus origin?

A trove of giant viruses was recently sequenced from the very same deep-sea sediments where Lokiarchaeota were discovered. He hopes someone will test whether any of these viruses can infect archaea and, if so, whether they build viral factories similar to those made by the NCLDVs that infect eukaryotes. Demonstrating that would be “game over.”

2022-11-12: Syntropic eukaryogenesis

Today, at the microbial mats in the Atacama Desert and other sites throughout the world, scientists are investigating what the earliest eukaryotic cells may have looked like, the partnerships they may have struck up with other organisms, and how their molecular machinery might have functioned and evolved. Already, the discovery of the Asgards has solidified certain aspects of eukaryogenesis while raising new questions about others. “I think this is the most exciting development in biology right now. So much is being discovered and so many predictions are being met. Eukaryogenesis is arguably one of the most important events in the history of life, after the origin of life itself.” Many scientists have rallied behind the idea that the first eukaryotes evolved out of a syntrophy between an archaeal host and bacteria that somehow found their way inside to become the organelles, such as nuclei and mitochondria, that distinguish eukaryotes. The details of these relationships remain murky, but mitochondria provide the most tantalizing clues to their origin story. “There’s DNA in mitochondria that we can somewhat clearly connect or trace back to alphaproteobacteria”. There are contrasting hypotheses as to how the alphaproteobacterium would have gotten inside an archaeal host, however. In the eukaryogenesis version of the chicken-and-egg conundrum, scientists go back and forth on whether mitochondria would have been necessary to power the energetically expensive process of phagocytosis, or whether phagocytosis would have had to arise first as the means of ingesting the symbiotic partner. When it comes to the nucleus, the picture is much less clear. Hypotheses of its origin run the gamut from a bacterial endosymbiont within an amoeboid host to the remnants of a giant virus.


2023-06-19: Lokiarchaeota aren’t the the origin of eukaryotes, but are closely related.

Eukaryotes are placed as a well-nested clade within Asgard archaea and as a sister lineage to Hodarchaeales, a newly proposed order within Heimdallarchaeia, consistent with the 2 domain tree of life scenario. Using sophisticated gene tree and species tree reconciliation approaches, we show that analogous to the evolution of eukaryotic genomes, genome evolution in Asgard archaea involved significantly more gene duplication and fewer gene loss events compared with other archaea. Finally, we infer that the last common ancestor of Asgard archaea was probably a thermophilic chemolithotroph and that the lineage from which eukaryotes evolved adapted to mesophilic conditions and acquired the genetic potential to support a heterotrophic lifestyle.

Universal Computing

take any physical process at all, and you should be able to simulate it using a universal computer. It’s an amazing, Inception-like idea, that one machine can effectively contain within itself everything conceivable within the laws of physics. Want to simulate a supernova? Or the formation of a black hole? Or even the Big Bang? Deutsch’s principle tells you that the universal computer can simulate all of these. In a sense, if you had a complete understanding of the machine, you’d understand all physical processes. Deutsch’s principle goes well beyond Turing’s earlier informal arguments. If the principle is true, then it automatically follows that the universal computer can simulate any algorithmic process, since algorithmic processes are ultimately physical processes. You can use the universal computer to simulate addition on an abacus, run a flight simulator on a silicon chip, or do anything else you choose.

2022-06-23: And now the reverse, trying to get the universe to do our computations.

McMahon and a band of like-minded physicists champion an unorthodox approach: Get the universe to crunch the numbers for us. “Many physical systems can naturally do some computation way more efficiently or faster than a computer can”. He cites wind tunnels: When engineers design a plane, they might digitize the blueprints and spend hours on a supercomputer simulating how air flows around the wings. Or they can stick the vehicle in a wind tunnel and see if it flies. From a computational perspective, the wind tunnel instantly “calculates” how wings interact with air. The physicists building these systems suspect that digital neural networks — as mighty as they seem today — will eventually appear slow and inadequate next to their analog cousins. Digital neural networks can only scale up so much before getting bogged down by excessive computation, but bigger physical networks need not do anything but be themselves.

Moebius

“In the supremely unstable universe of Moebius, characters exist and abruptly change in accordance with their creator’s fluctuating whims, an aspect of his art that became a central premise, to great comic effect. (It is awkward when one’s body suddenly shifts its form, improbably and ridiculously, a point that became the hilarious core of the early story “Shore Leave on Pharagonesia” and remained a reliably satisfying spice throughout the later works.) And Moebius, who liked to abandon himself to the flow of improvisation, produced a steady rhythm of surprises in other ways. Le garage hermétique, composed as a serial with very short chapters, reflects an anarchic authorial game in which its creator deliberately introduced new and abrupt conceptual complications each month to destroy the story’s coherence and give himself problems to which he would then have to invent solutions in the subsequent month’s installment—at which time, of course, he would also introduce further complications to destroy the coherence he had just achieved, to pose a new challenge for next time. As he later explained, this state of “insécurité permanente”—the desire it inspired in him to re-create consistency and the satisfaction of then doing so—brought him “un délice absolu” (“absolute delight”)….”

moebius is my favorite comic artist. his stuff is absolutely fantastic.

Social media

2022-10-05: Social media as we’ve known it is probably doomed

Whether a decline in social media would on balance be good or bad for society I’ll leave to another discussion, but the handwriting is on the wall for a major decline in social media overall.
As with most predictions, the timing and other details will surface in coming months and years, but the overall shape of things to come is not terribly difficult to visualize.
The fundamental problem is also clear enough. A vast range of entities at state, federal, and international levels are in the process of enacting, invoking, or otherwise planning a range of regulatory and other legal mandates that would apply to social media firms — with many of these requirements being in direct and total opposition to each other.
The most likely outcome from putting these firms “between a rock and hard place” will be a drastic reduction of social media services provided, resulting in a massive decrease in ordinary persons’ ability to communicate publicly, rather than the increase that various social media critics have been anticipating.

Becoming a disney character

Our posthuman future made cute by disney.

Disney is teaming up with Open Bionics to provide royalty-free use of various character hands for children who’ve lost a limb! Open Bionics is thrilled to announce the next generation of bionic hands for young amputees. From the Marvel Universe, hot out of Tony Stark’s workshop, the Iron Man hand. Now kids can get excited about their prosthetics. They won’t have to do boring physical therapy, they’ll train to become heroes. They’re not just getting medical devices, they’re getting bionic hands inspired by their favorite characters. The Walt Disney Company is generously donating the time of its creative teams and providing royalty free licenses. More designs coming soon!”