What'sNEW

30 Jan 2023What'sNEW about HGT
"Sedimentary DNA can influence evolution: Establishing mineral facilitated horizontal gene transfer as a route to bacterial fitness," by Taru Verma et al., doi:10.1101/2023.01.24.525235,
bioRXiv, 24 Jan 2023; and commentary by Keith Cowing, 29 Jan 2023.
Viruses and Other Gene Transfer Mechanisms has a primer and many examples of HGT.

29 Jan 2023
Wet Panspermia?!...                       The simplest form of life we know is a single prokaryotic cell. Nothing less could bring life to a lifeless planet. Of course eukaryotic cells also could, and viruses may easily hitchhike along with cells. These microbes, frozen inside comets for example, could persist indefinitely and arrive on a planet intact, perhaps descending as dust. Multicellular life would have more trouble. That's why cosmic ancestry adopts the definition of Panspermia that we have.

Definition of panspermia to be updated But this definition is incomplete. Astrobiologist Devid Tepfer has long advocated plant seeds as vectors for panspermia. Ted Steele et al. suggest cryo-preserved embryos of larger animals may survive in comets. Moreover, life in a comet may not always be dormant. A periodic pass close to a star could warm the comet enough to melt ice and allow cells to multiply.

Even far from stars, radioactive elements with long half-lives could warm a comet interior, as Hoyle and Wickramasinghe knew. Now Richard Hoover expands on that idea, suggesting that radioactivity may allow for "the transfer of intact biospheres across interstellar and possibly intergalactic distances." He's calling it "Wet Panspermia."

David Tepfer and Sydney Leach, "Plant Seeds as Model Vectors for the Transfer of Life Through Space," doi:10.1007/s10509-006-9239-0,
Astrophysics and Space Science, 15 Nov 2006.
Ted Steele et al., "Cause of Cambrian Explosion - Terrestrial or Cosmic?" doi:10.1016/j.pbiomolbio.2018.03.004, Progress in Biophysics and Molecular Biology, online 13 Mar 2018.
Richard B. Hoover, "Meteorites comets, rogue planets and the distribution of biosphere" [abstract], at the World Conference on Basic Sciences and Sustainable Development, Belgrade, Serbia, 19-22 Sep 2022.
13 Jan 2023 (book review): Kevin Peter Hand thinks whole biospheres might cross a galaxy.
Introduction and ...New Questions have more about the word "panspermia."

Stanley Phillip Franklin, co-founder of the Institute for Intelligent Systems at the University of Memphis
28 Jan 2023
Stanley Phillip Franklin, co-founder of the Institute for Intelligent Systems at the University of Memphis, died at home, 23 Jan 2023. He was also a founding Advisory Director of the Astrobiology Research Trust, the sponsor of this website. And he was a valued friend and advisor to me. I will miss him.
"Dr. Stan Franklin dies: Memphis genius pioneered 'Artificial Intelligence'" by John Beifuss,
Memphis Commercial Appeal, 26 Jan 2023.
Stan Franklin, IIS, U of M.
Astrobiology Research Trust

15 Jan 2023
Ari Abramóvich Shtérnfeld published an essay, in 1935, suggesting that Titan has an atmosphere and possibly life. This and much more are found in a new retrospective article.
"Brief review about history of astrobiology" by Bruno Leonardo do Nascimento-Dias and Jesús Martinez-Frias,
International Journal of Astrobiology, online 19 Oct 2022.

13 Jan 2023
Kevin Peter Hand learned about astrobiology with Chris Chyba, and James Cameron introduced him to deep seafloor exploration. Loving that, Hand was among the very first to see some of the unusual life swaying or swimming near hydrothermal ocean vents. As a NASA-affiliated astrobiologist, he now advocates missions to look for life in Alien Oceans, the ones under the ice of moons like Europa. He tells a captivating story. Alien Oceans by Kevin Peter Hand

And Hand makes it instructive. When he sees a need, he uses helpful analogies to remind us of the relevant science. He explains how different missions and different scientists with different instruments and methods progressively enabled us to reach our current understanding of other worlds. For example, some bodies have magnetic fields that are intrinsic, some that are induced, some, none at all. Each case holds important clues about the structure of that world.

Hand can also be quite imaginative about the life that might be found in those oceans. Could an underwater civilization develop metallurgy, or advanced technology? I gladly welcome such free-thinking. He also considers at length whether life elsewhere could use entirely different chemistry from ours. I think we first need to better understand life-as-we-know-it.

I'm puzzled: why doesn't panspermia get mentioned? He wonders if inhabited moons or planets might get thrown out of orbit and "transport biospheres across the galaxy" (p 134). Heck, that's panspermia, wholesale. For finding extra-terrestrial life, he writes, "the easiest and most intuitive biosignature is perhaps the one you can judge with your own eyes: its morphology" (p 238). He must be unaware of the morphology photographed by the Opportunity rover on Mars, 27 Feb 2004. His account of the search for life by the earlier Viking mission, 1976-1977, sticks closely to NASA's hyper-conservative party line. At least he plainly admits, "There has been only one time in the history of space exploration when looking for signs of life was the stated target of the mission [Viking]. …this first time was also the last time" (p 231). If this frustrates him, he says no more about it.

Of course Hand does not stray from orthodoxy as far as I do. Still, this book moves the paradigm in the right direction. For a bonus, it's edifying and enjoyable. Recommended!

Alien Oceans: The Search for Life in the Depths of Space by Kevin Peter Hand, Princeton University Press, 07 Apr 2020.
Life on Europa, Other Moons, Other Planets? has related links.
Life on Mars! has more about Viking and a link for Opportunity sol 34.

07 Jan 2023
Nature, Dec 2022
New studies suggest that recently identified archeabacteria evolved into eukaryotes, writes Elizabeth Pennisi in Science. Some species of Asgard are seen to have complex shapes and internal features resembling the eukaryotic cytoskeleton. Genes once thought exclusive to eukaryotes are found in these archaea. Some of the genes must be behind the surprising features. The story comes across as more evidence in favor of the mainstream theory of evolution. "Until recently, life's journey towards complexity was a blur."

The trouble is, those eukaryotic genes lack any discernable neo-darwinian provenance. They're just already installed in archaea. If we ask how the genes originated, mainstream theory has nothing to offer. A better question is, Where do these eukaryotic genes come from? Apparently, they come by HGT, possibly from archaea. Before archaea, the trail vanishes abruptly. This evidence supports evolution by cosmic ancestry.

"Did ancient tentacled microbes kick-start complex life?" by Elizabeth Pennisi, Science, 06 Jan 2023.
"Actin cytoskeleton and complex cell architecture in an Asgard archaeon," by T. Rodrigues-Oliveira, F. Wollweber, R.I. Ponce-Toledo et al., doi:10.1038/s41586-022-05550-y, Nature, 21 Dec 2022.
07 May 2015 and 09 Oct 2015: Genes for Eukaryotic Signature Proteins in Archaea.
Viruses and Other Gene Transfer Mechanisms has more.
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