Evidence suggests part of key gene needed for insect reproduction came from bacterial genomes
|03 Jun 2020||
What'sNEW about HGT |
Horizontal helper [human interest story] by Peter Reuell, The Harvard Gazette, 02 Jun 2020.
Viruses and Other Gene Transfer Mechanisms has background and many other examples.
Thanks, Google Alerts and Stan Franklin.
... there is a realistic possibility that Mars hosts indigenous microbial life, according to a number of experts on astrobiology and related topics. They met last November in New Mexico to discuss, among other things, "measurement techniques that could be used to detect evidence of extant life (if present)." We wonder if the Chiral Labelled Release experiment proposed by Gil Levin was considered. The original LR experiment on the Viking missions got positive results for life on Mars in 1977. Subsequently the results were attributed to unanticipated chemical reactions. The chiral version could easily tell the difference.
Mars Extant Life: What's Next? Conference Report, Astrobiology, online 28 May 2020.
Life on Mars!: mentions the Viking LR experiment with updates.
A brief history of astrobiology from the UK omits the most important UK astrobiologists of all, Fred Hoyle (1915-2001) and Chandra Wickramasinghe (b. 1939). Their analysis of interstellar dust produced a series of discoveries that pointed to life in space, and astrobiology was launched. What was Cockell thinking?! Correcting links follow.
Astronomy + biology by C.S. Cockell, Astron. & Geophys., Jun 2020.
Astronomy + Biology revisited by Wickramasinghe et al., invited response, Astron. & Geophys., 31 May 2020.
The Beginnings of Astrobiology | local PDF, Chandra Wickramasinghe, Int. J. Astrobiol., 30 Sep 2002.
The case for life as a cosmic phenomenon by F. Hoyle and N.C. Wickramasinghe, Nature, 07 Aug 1986.
Hoyle and Wickramasinghe's Analysis of Interstellar Dust: our brief history with references, links and updates.
Fred Hoyle Interviewed... and
Chandra Wickramasinghe have more.
An asteroid with a tail like a comet has been located by a monitoring system with telescopes around the globe. This asteroid orbits along the same path as Jupiter and is thought to have been there, inactive, for billions of years. Now its contents are venting or erupting out, leaving a visible tail. (But see update below.)
UH ATLAS telescope discovers first-of-its-kind asteroid, Institute for Astronomy, University of Hawaii, 20 May 2020.
Freaky 'Active' Object in Jupiter's Orbit Is First of Its Kind Seen by Astronomers by George Dvorsky, Gizmodo, 21 May 2020.
Thanks, Rob Cooper.
Comets: The Delivery System has background and updates.
Bacteria... can remain viable for billions of years, we believe. Leslie Orgel agrees.
UPDATE: Jupiter Has Trapped a Comet in a Bizarre Orbit by Jeff Hecht, Sky & Telescope, 28 May 2020.
Astronomers recategorize asteroid-like comet..., University of Hawai'i News, 26 May 2020.
This evolutionary history implies that the Jezero-lake floor would have... hosted an active environment of significant astrobiological importance.
Estimated Minimum Life Span of the Jezero Fluvial Delta (Mars) by Francesco Salese et al., Astrobiology, 20 May 2020.
Life on Mars! has lots more.
Our hemoglobin evolved by duplication, divergence and recombinations of ancient gene sequences, according to an international team coordinated at the University of Chicago. The project aimed to reconstruct the evolutionary history of vertebrate hemoglobin by reasoning backward from today's genetic sequences. It's similar to the analysis of snake venom reported yesterday.
This project is also deep and thorough, and the results are impressive. But both teams traced the "origins" of the studied genetic programs to pre-existing ancient genes. Thus, the kernels of the programs apparently were available already. If so, the tinkering to unlock their potential, while not inventive, is still remarkable.
Here we use ancestral protein reconstruction and biophysical assays to elucidate the origins of vertebrate haemoglobin.... We show that modern haemoglobin evolved from an ancient monomer and characterize the historical 'missing link' through which the modern tetramer evolved—a noncooperative homodimer with high oxygen affinity that existed before the gene duplication that generated distinct... subunits.
Origin of complexity in haemoglobin evolution by Arvind S. Pillai et al., doi:10.1038/s41586-020-2292-y, (+alternate); and commentary:
Extinct proteins resurrected to reconstruct the evolution of vertebrate haemoglobin by Michael Berenbrink, Nature, 20 May 2020.
Duplication... has updates.
Testing Darwinism... has relevant comments.
Genes Older Than Earth? is consistent with the possibility that evolution is actually development.
Robust Software Management... acknowledges that unlocking the hidden potential of genes is remarkable.
Where do new genes come from? A favored answer from standard darwinian theory is gene duplication, as Susumo Ohno suggested fifty years ago. After duplication, the new alleles can diverge. If the parent gene contained two or more functions, each daughter allele may specialize in one of them. This process, "subfunctionalization," is well observed.
Another outcome, called "neofunctionalization," is supposed to produce functions that were not contained in the original gene. Rattlesnake venoms provide a vivid example, according to new research using sequence data to reconstruct the evolution of those genes. We are awed by the scope and depth of the study. Its claims are not exaggerated.
|Here, we have traced the origin and diversification of one prominent family, the snake venom metalloproteinases (SVMPs) that play key roles in subduing prey in many vipers. ...We have shown that the that this 30-gene complex has been massively expanded in the rattlesnake lineage from a single, deeply conserved ancestral disintegrin and metalloproteinase (adam28) gene. In addition, we have identified a series of stepwise intragenic deletions that gave rise to three major classes of secreted SVMP toxins by the successive removal of [three domains]. ...These findings allow us to reconstruct the genetic path of snake venom SVMP innovation ...and to consider which evolutionary forces may best explain their genesis. ... there is no doubt that the massive expansion and diversification of SVMP genes that encode major components of prey-killing venom has involved episodes of positive selection. ...the SVMPs present a case of neofunctionalization via domain loss.
The origin and diversification of a novel protein family in venomous snakes by Matt W. Giorgianni, Noah L. Dowell, Sam Griffin, Victoria A. Kassner, Jane E. Selegue, and Sean B. Carroll, doi:10.1073/pnas.1920011117, 10 pages, open access, PNAS, 19 May 2020.
Duplication... has become our main webpage about the reach of neofunctionalization.
Testing Darwinism... includes comments about historical reconstructions like this one.
Evidence for Life on Mars deserves another look according to four astrobiologists studying photos taken by NASA's Opportunity rover. The abundant "blueberries" are not likely to be mineral accretions, they first explain. More importantly, many of the blueberries seem to grow like mushrooms on stalks, and lean the same way as if aiming for sunlight. (Cropping, right, from sol 88; click for NASA source.)
Blueberries seen with the Microscopic Imager in 2007 grew noticeably and new ones appeared in only 3 days (sols 1145-1148; paired images below).
Life on Mars: Colonies of Photosynthesizing Mushrooms in Eagle Crater? The Hematite Hypothesis Refuted by Rhawn Gabriel Joseph, R. A. Armstrong, Giora J. Kidron and Rudolph E. Schild, doi:10.37720/jassr.04172020, Journal of Astrobiology and Space Science Research, 38 pages, many images, 19 Apr 2020.
Thanks, Stan Franklin.
Opportunity: All 228,771 Raw Images, Mars.NASA.gov.
This blueberry, like some others, has a seam like a peach.
Life on Mars! is our related webpage.
We show that somatic RNA can be transported to the germline and passed on to embryos....
|12 May 2020||
What'sNEW about HGT |
Direct evidence for transport of RNA from the mouse brain to the germline and offspring by Elizabeth A. O'Brien, Kathleen S. Ensbey, Bryan W. Day, Paul A. Baldock and Guy Barry, doi:10.1186/s12915-020-00780-w, BMC Biology, 30 Apr 2020.
We hypothesized that RNA may be transported from a somatic tissue ...of an adult male mouse to the germline, and subsequently to embryos. To investigate this, we injected one hemisphere of the male mouse striatum with an AAV1/9 virus expressing human pre-MIR941 (MIR941). After 2, 8 and 16 weeks following injection, we ...[detected] the presence of virus and human MIR941 in brain, peripheral tissues and embryos, from injected male mice mated with uninjected females. ...[A] small percentage (~ 1-8%) of MIR941 is transported to the germline and to embryos in about a third of the cases.|
Viruses and Other Gene Transfer Mechanisms has related discussion and all updates.
James Powers has comments, 16 May 2020.
...E. coli (a prokaryote) and a much more complex single-cellular microorganism such as yeast (a eukaryote) can thrive in a pure H2 gas environment....
— Sara Seager et al., 2020
Microbes transported by comets may land on environments that are very unlike Earth. Cometary panspermia is more logical and more likely if microbes are able to survive and multiply in a wide variety of worlds. And indeed they can. New evidence from MIT only widens the proven range. But this versatility has no ready explanation in standard evolutionary theory, if microbes have survival capabilities that were never deployed or needed on Earth.
Laboratory studies on the viability of life in H2-dominated exoplanet atmospheres by Sara Seager et al., doi:10.1038/s41550-020-1069-4, Nature Astronomy, 04 May 2020.
Planets with hydrogen-rich atmospheres could harbor life by Lisa Grossman, Science News, 04 May 2020.
Thanks, Stan Franklin.
Bacteria: The Space Colonists has lots about their hardiness.