What'sNEW Archives, November - December 19981998, December 18: Scientists in Germany and California report finding the unique signatures of an exotic form of carbon in deep space. This means that organic chemistry is abundant in the universe, implying that carbon-based life could be possible throughout the universe. This research specifically analyzes the "diffuse interstellar bands," specific bands in the spectra of starlight that are partially dimmed by interstellar matter. The intervening matter now appears to be polycyclic aromatic hydrocarbons (PAHs). The report suggests that the PAHs are prebiotic, although the ones found on Earth are postbiotic. In any case, the study of complex organic compounds in space, considered questionable thirty years ago, is now fully established and respectable.
Henning, Th. and F. Salama. "Carbon in the Universe" p 2204-2210 v 282 Science. 18 December 1998. [Abstract]
1998, December 11: The genome of a tiny worm contains many genes with no similarity to previously known genes. A series of articles in Science consider the newly sequenced Caenorhabditis elegans genome and compare it to that of Saccharomyces cerevisiae (yeast), the only other sequenced eukaryote. A set of highly conserved proteins carry out core biological processes shared by these two eukaryotes. But the multicellular eukaryote has a system of protein regulators and signal transducers that is significantly more complex than that in unicellular organisms. The observations suggest that the very large difference in the total number of different proteins encoded by the two organisms (~3.1-fold higher in worm) is not accounted for by endless close variations in the clusters found among the shared set, but instead are proteins that are substantially different in sequence (Chervitz et al.) This finding is consistent with (but does not prove, of course) our thesis that evolution to more highly organized forms of life requires new genes that do not arise by the random mutation and recombination of existing genes.
The C. elegans Sequencing Consortium. "Genome Sequence of the Nematode C. elegans: A Platform for Investigating Biology" p 2012-2018 v 282, Science, Dec 11, 1998. [Abstract]
1998, November 30: Four biologists from Indiana University have found evidence that an intron was installed into a certain gene in angiosperms by cross-species horizontal transfer over 1,000 times during angiosperm evolution. "This massive wave of lateral transfers is of entirely recent occurrence, perhaps triggered by some key shift in the intron's invasiveness within angiosperms," they say. Whatever triggered the transfer and made it so successful, the example further demonstrates that the targetted horizontal transfer of specific long segments of DNA can be a vigorous evolutionary process.
Cho, Yangrae; Yin-Long Qiu; Peter Kuhlman; and Jeffrey D. Palmer. "Explosive invasion of plant mitochondria by a group I intron " p 14244-14249 v 95 n 24, Proc. Nat. Acad. Sci., USA., November 24, 1998. Abstract
1998, November 30: Scientific consensus for the Mars microbes is weakening. Most of the papers presented at a meeting of the Lunar and Planetary Institute in Houston, Texas, November 2-4, contended that the meteorite named ALH 84001 does not contain evidence proving that there was once life on Mars. One of the main arguments is that the alleged nanobacteria would be too small to contain the minimum number of genes and other equipment needed for a basic cell. Cosmic Ancestry agrees that cells 50 nanometers in diameter are too small to be independently viable. But nanobacteria — also found on Earth — might well be byproducts of larger viable cells under stress, as Russian microbiologist Mikhail Vainshtein et al. suggest. Other meeting highlights: some of the biological looking fossil shapes can also be made by chemical processes; and the PAHs (polycyclic aromatic hydrocarbons) in the meteorite might merely be fossils from Mars' prebiotic soup! Still standing is the peculiarity of the magnetite crystals. Only magnetotactic bacteria — no known chemical processes — are known to make them in the form found in the meteorite.
As an aside, Cosmic Ancestry wonders why mainstream neo-Darwinism doesn't embrace the possibility that nanobacteria are a stage of "precellular life." Doesn't the RNA world require just such a thing?
Workshop on "Martian Meteorites: Where Do We Stand and Where Are We Going?" A Review of Presentations Emphasizing Martian Meteorite ALH 84001, from the LPI conference in Houston, Texas, 2-4 November 1998.
1998, November 18: NASA acknowledges that a major paradigm shift is under way. The newly formed Astrobiology Institute has upgraded its website, and with the new look comes a new attitude toward life from space. The "Overview" page carries a heading, "Paradigm Shift," with ten bullet points relating to this new attitude and the recent scientific developments behind it. For example: Life has been found to exist under conditions previously thought impossible.... Comets and asteroids strongly influence planetary evolution.... Natural processes such as comet and asteroid impacts can cause the transfer of material from one world to another sufficiently quickly and with sufficient gentleness to preserve the microbial life within it (if any). The Astrobiology home page also carries links to recent news items such as today's Comet "Brings Extraterrestrial Life" - Two astronomers believe comets deposit microscopic life forms on Earth from The Times of London. In fact, the British media attention to panspermia is noteworthy by itself. During the excitement over the Leonids meteor shower, the most respected newspaper in England is giving the aforementioned frontpage coverage to Hoyle and Wickramasinghe's theory that comets carry life. Meanwhile another respected London newspaper, The Independent is running a letter from Wickramasinghe and Hoyle entitled "Microorganisms from the Leonid Meteor Stream." Change seems to be afoot.
Astrobiology from NASA's Ames Research Center.
1998, November 3: Two geneticists find evidence for "a predominating integration mechanism," that inserts acquired foreign genes into genomes in clustered fragments. The researchers from the University of Minnesota bombarded Avena sativa (oat) cells with specially engineered plasmids, to see whether and how the new strands would become inserted into the oat genome. "In all transformation events, the transgenic DNA integrated into the plant genome consisted of intact transgene copies that were accompanied by multiple, rearranged, and/or truncated transgene fragments." One of the geneticists, Somers, commented by e-mail that while there is not much additional published evidence for a predominating mechanism to integrate new genes in this way, he is finding similar structures in other oat strains — and his colleagues see them even in fish. Where the structures occur naturally, he wonders, "Are these the footprints of primitive alien integrations?" Cosmic Ancestry wonders if a similar mechanism might account for the interrupted structure of almost all genes in eukaryotes.
Pawlowski, Wojciech P. and David A. Somers. "Transgenic DNA integrated into the oat genome is frequently interspersed by host DNA" p 12106-12110 v 95 n 21, Proc. Nat. Acad. Sci., USA. October 13, 1998. Abstract.