August 14 If my previous column mentioned a book by a Eugene, this one mentions a book about a Eugeni.
Read on to know more about that. Though this column is really about certain tiny worms that lived tens of thousands of years ago and have been brought back to life, to the extent that they have reproduced. Though as you will find, they did so by "evading the cost of sex". Whether that's a good thing, or even a good characterization, I'll leave for you to answer. (But tell me, please oh please.) In Mint on August 4: Frozen worms and the cost of sex, https://www.livemint.com/opinion/columns/when-a-worm-wriggles-back-to-life-after-46-000-freezing-years-in-siberia-11691089845893.html cheers, dilip --- Frozen worms and the cost of sex Indulge me while I begin a second consecutive column with memories of a book. In this case it's Richard Ben Sapir's novel "The Far Arena", which I first read as a teenager. It's the story of Eugeni, a gladiator from Rome of the first century. But get this: it is not set in the first century, but in contemporary times. No, Eugeni is not a Methuselah twice-over, an old man who has somehow lived close to 2000 years. He's in the prime of his life, but finds himself situated in the modern world. How does this happen? Now of course this is science fiction. The premise of the novel is that Eugeni was frozen in ice in the first Century. Nearly two thousand years later, an oil company finds his frozen body. Comes a scientist interested in cryonics - the preservation of human body parts at low temperatures, with the intent of resurrecting them in the future. The scientific establishment today dismisses cryonics as pseudo-science, but this is a novel, after all. So while clearly Eugeni was presumed dead back in the first century, this scientist assumes that actually, his body went into a kind of indefinite stasis. He decides there's a chance to revive Eugeni. That's just what happens. Eugeni returns to life in the late 20th Century. As you can imagine, what happens to him afterward makes for a gripping story, not least because he and his modern-day acquaintances have a hard time relating to each other. Though of course I'm not trying to tell you that story here. Instead, what interests me is the idea of life being frozen for so long, and then revived. Eugeni is a fictional character and cryonics is viewed with serious scepticism. But leave that aside, stop reading the novel and think for a few moments of this: is this kind of suspension and later resurrection of life possible at all? If not with humans, what about plants? Other animals? Amazingly, the answer seems to be "Yes". Scientists have known for a while about what they call "cryptobiosis", in which organisms will slow down their body metabolisms to near zero. Doing so, they enter what is essentially a deep sleep. They do this to survive extreme weather conditions that might otherwise kill them. The "hope", not that I'm suggesting they necessarily have one, is that they can come back to life - or be brought back to life - when conditions improve. In 2014, for example, some scientists looked at moss ("Millennial timescale regeneration in a moss from Antarctica", Esme Roads et al, Current Biology, 17 March 2014). Mosses, they observed, "have well-developed stress tolerance features permitting cryptobiosis." Till then, the longest period of cryptobiosis observed had been 20 years. But these scientists found "small moss clumps" that had been covered in ice on Antarctica for 400 years. They were able to successfully regrow that moss. At the other end of the world a few years later, a team of scientists recovered "bdelloid rotifers" - not some exotic cousin of Rottweiler dogs, but microscopic multicellular animals - from Siberian soil samples that had been below freezing point temperatures for about 24,000 years ("A living bdelloid rotifer from 24,000-year-old Arctic permafrost", Lyubov Shmakova et al, Current Biology, 7 June 2021). This was, they commented, "the longest reported case of rotifer survival in a frozen state." Survival, because they recovered "numerous living rotifers". They then subjected these microscopic creatures to what more modern cousins might endure in the course of their lives: freeze them and attempt revival. This showed that there was no significant difference in the freeze-tolerance of ancient species and contemporary ones. In other words, it was not just that the rotifers that had been frozen for 24,000 years could be revived. It was also that, unlike Eugeni, they could live pretty normally in these modern times. Still, you wonder, what about slightly larger animals? What about, say, worms? Glad you asked. Last month, still other scientists published a paper that reports on a species of nematode - a roundworm - that was originally collected from Siberian permafrost in 2002 ("A novel nematode species from the Siberian permafrost shares adaptive mechanisms for cryptobiotic survival with *C. elegans* dauer larva", Anastasia Shatilovich et al, PLOS Genetics, 27 July 2023, https://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1010798). While nematodes are not microscopic, they are only about a millimeter long, so still tiny. They are also found all over the planet - in soil, in rivers, on the floor of the ocean and more. A particular species of nematode, *Caenorhabditis elegans*, is also commonly used in laboratory experiments around the world. So the scientists had a familiar animal to compare the Siberian specimens to. First, they reported the startling result of radio-carbon dating the Siberian nematodes: these "individuals have remained in cryptobiosis since the late Pleistocene (~46,000 years)." This makes them what a Scientific American report called "by far the most stunning examples of ... cryptobiosis - an organism's ability to suspend its own metabolism in poor conditions." Being dated to the Pleistocene Age is one thing, but can this suspended metabolism be revived? That's just what these researchers set out to answer. First, they thawed the soil sample, doing it over several weeks so as not to bake the nematodes to death. Eventually, "motile nematodes were detected" - meaning the worms were doing what worms do, wriggling about. They started consuming the bacteria the scientists had helpfully provided for food. There was more to come. The scientists named this nematode *Panagrolaimus kolymaensis*, after the Kolyma river in Russia where the samples were collected. In many ways, it wasn't unique. They found similarities to *C. elegans*, and those suggest many nematodes can potentially "suspend life over geological time scales." Besides, some selected *P. kolymaensis* females actually began producing babies via a process called "parthenogenesis", in which males are not required. Think of the implication: "otherwise extinct lineages" of some species can be re-started, if you like, if you can find an individual that has been in cryptobiosis for even tens of thousands of years. The scientists found this "particularly interesting ... as each individual can find a new population [by] evading the cost of sex." Yes: if you find such an individual, it might even "evade the cost of sex." I wonder if it can or will ever forgive you. Wish we could have asked Eugeni. -- My book with Joy Ma: "The Deoliwallahs" Twitter: @DeathEndsFun Death Ends Fun: http://dcubed.blogspot.com -- You received this message because you are subscribed to the Google Groups "Dilip's essays" group. To unsubscribe from this group and stop receiving emails from it, send an email to dilips-essays+unsubscr...@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/dilips-essays/CAEiMe8rPXtn3i3eUo%2B1ewDqoh9rJ%2BNQKhrzYvdFRPkXSBWxvig%40mail.gmail.com.