What'sNEW Archives, July - October 1998

The dating of a fossilized worm track which would have supported the older divergence times has been challenged. A cover story in the October 2 issue of Science described what the authors argue are fossilized worm burrows in 1.1 billion-year-old sediments. If so, this evidence would support the neo-Darwinian response to the otherwise anomalous molecular clock data — metazoans must be twice as old as the Cambrian explosion. But a subsequent story in Nature suggests that the sediments bearing the worm tracks may be no older than the Cambrian explosion, about 540 million years ago. And the controversy continues. At the annual meeting in Toronto of the Geological Society of America, during the week of October 26, paleontologists presented both sides of the argument over the date of the sediments. Cosmic Ancestry holds that there is not necessarily any conflict between the data from the fossil record and from molecular clocks, because genes may be much older than the time when they are first expressed.

Bromham, Lindell; Andrew Rambaut; Richard Fortey; Alan Cooper and David Penny. "Testing the Cambrian explosion hypothesis by using a molecular dating technique," p 12386-12389 v 959 n 21, Proceedings of the National Academy of Sciences USA, 13 October 1998. Abstract.
Seilacher,Adolf; Pradip K. Bose and Friedrich Pflüger. "Triploblastic Animals More Than 1 Billion Years Ago: Trace Fossil Evidence from India," p 80-83 v 282 n 5386, Science, 2 October 1998. Abstract.
Kerr, Richard A. "Tracks of Billion-Year-Old Animals?" p 19-21 v 282 n 5386, Science, 2 October 1998. Abstract.
Brasier Martin. "Animal evolution: From deep time to late arrivals" p 547-548 v 395, Nature, 8 October 1998. Article.
Normile, Dennis. "New Views of the Origins of Mammals" p 774-775 v 281, Science, 7 August 1998. Summary.
Earliest Animals Old Again?, by Richard A. Kerr and Lava Bagla, ScienceNOW, 3 November 1998.
Metazoan Genes Older Than Metazoa? is a related Cosmic Ancestry webpage.

1998, October 23: The genome of Chlamidia trachomatis contains some 35 eukaryotic genes, confirming that the transfer of genes between bacteria and eukaryotes is not rare. This bacterium causes the most common bacterial sexually transmitted disease in the United States. Its small genome of 1,042,519 nucleotide pairs (main chromosome) plus 7,493 nucleotide pairs (a plasmid) has just been published by Richard S. Stephens of the University of California, Berkeley, et al. Thirty-five of its estimated 894 genes, almost 4%, appear to be derived from eukaryotes. Even more surprising, many of the eukaryotic genes seem to come from plants. The Chlamidia bacterium is not known to infect plants. The mainstream response is to propose a relationship between chlamidia and plant predecessors, over 500 million years ago, with one-way transfer of genes to the bacteria. Cosmic Ancestry already predicts that bacteria and eukaryotes swap genes, in both directions. We suggest that the evidence for lateral gene transfer in this new sequence counts in favor of Cosmic Ancestry.

Stephens, Richard S.; Sue Kalman; Claudia Lammel; Jun Fan; Rekha Marathe; L. Aravind; Wayne Mitchell; Lynn Olinger; Roman L. Tatusov; Qixun Zhao; Eugene V. Koonin and Ronald W. Davis. "Genome Sequence of an Obligate Intracellular Pathogen of Humans: Chlamydia trachomatis," p 754-759 v 282 n 5389, Science, 23 October 1998.
Hatch, Thomas. "Chlamydia: Old Ideas Crushed, New Mysteries Bared," p 538-639 v 282 n 5389, Science, 23 October 1998.
Chlamydia's Secrets Laid Bare, by Cristie Aschwanden, ScienceNOW, 22 October 1998.
Viruses... and the two pages following it are related Cosmic Ancestry webpages. [Next-What'sNEW about HGT-Prev]

1998, October 22: Callisto, like another of Jupiter's moons, Europa, may have an underground liquid ocean and at least some of the basic ingredients for life. Dr. Krishan K. Khurana of UCLA and colleagues discovered that its magnetic field fluctuated in time with Jupiter's rotation. The best explanation was that Jupiter's powerful magnetic field was creating electrical currents within a salty ocean under the frozen surface of Callisto.

Khurana, K. K.; M. G. Kivelson; D. J. Stevenson; G. Schubert; C. T. Russell; R. J. Walker and C. Polanskey. "Induced magnetic fields as evidence for subsurface oceans in Europa and Callisto," p 777-780 v 395, Nature, 22 October 1998.
Neubauer, Fritz. "Planetary science: Oceans inside Jupiter's moons," p 749-751 v 395, Nature, 22 October 1998.
Callisto makes a big splash, Space Science News from NASA's Marshall Space Flight Center, 22 October 1998.
Jupiter's Moon Callisto May Hide Salty Ocean, from ScienceDaily, 22 October 1998.
Life on Europa... has links to WhatsNEW on Jupiter's and other moons.

1998, October 22: Observations of famous Comet Hale-Bopp show amazingly strong activity of this unusual object, about 1,000 million kilometers (6.7 AU) from the Earth and the Sun.... Of particular interest is the observed emission from methanol (CH3OH) and hydrogen cyanide (HCN) molecules, never before detected in any comet this far away. The observations are being made with the 15-m Swedish-ESO Submillimetre Telescope (SEST) at the La Silla Observatory. The small image here was taken on October 19, 1998, in visible light and with the DFOSC instrument at the Danish 1.5-m telescope on La Silla. Although well beyond Jupiter's orbit, it is very obvious that strong nucleus activity is still present.

New Observations of Comet Hale-Bopp from La Silla, ESO Press Release 16/98, 22 October 1998.
Comets: the Delivery System is a related Cosmic Ancestry webpage.

1998, September 8: Fossilized magnetotactic bacterium identified in the Orgueil meteorite. Thirty years after Tan and VanLandingham photographed a "filamentary microstructure" in a carbonaceous chondrite, new knowledge has enabled scientists to identify it. Russian bacteriologist Mikhail Vainshtein says it is obviously a magnetotactic bacterium. (Thanks, Richard Hoover, for supplying the photos.)

Fossilized Magnetotactic Bacterium in the Orgueil Meteorite, a Cosmic Ancestry webpage, contains the picture and story.
A Reply to Cosmic Ancestry discusses the possibility that the fossil is an earthly contaminant.

1998, August 25: We owe the repertoire of our immune system to one transposon insertion, which occurred 450 million years ago in the ancestor of the jawed fishes. So comments Nature on a major discovery by a team from the Yale University School of Medicine. After an elegant series of experiments the biology team concludes, "a pivotal event in the evolution of the antigen-specific immune system was the insertion of a 'RAG transposon' into the germ line of a vertebrate ancestor." The transposable element carried two new genes which confer almost unlimited responsiveness on our immune system. This event would constitute a spectacular example of the evolution of a specific new feature after the transfer of a single strand of DNA. The feature was apparently a complete novelty, 450 million years ago, because nothing similar exists among the unjawed vertebrates. If so, those genes could not have earlier evolved toward their current function by the neo-Darwinian mechanism. Nature's commentator concludes with awe, "...In fact, we owe our life to the RAG transposase." In Cosmic Ancestry, insertion events like this one with important, sometimes immediate consequences are the way evolution works. We expect many other examples to be discovered.

Agrawal, Alka; Quinn M. Eastman and David G. Schatz, "Transposition mediated by RAG1 and RAG2 and its implications for the evolution of the immune system," p 744-751 v 394, Nature, 20 August 1998. Abstract.
Plasterk, Ronald, "Ragtime jumping," p 718-719 v 394, Nature, 20 August 1998. Link.
Pennisi, Elizabeth, "How the Genome Readies Itself for Evolution," p 1131-1134 v 281, Science, 21 August 1998. Summary
Bushman, Frederic, "Chapter 11: A Transposon Progenitor of the Vertebrate Immune System" p 339-364, Lateral DNA Transfer, Cold Spring Harbor Laboratory Press, 2002.
Ancient "Jumping DNA" May Have Evolved into Key Component of Human Immune System, HHMI news, 20 August 1998.
Single Switch Triggers Two Immune System Genes, HHMI news, 13 August 1999.
Neo-Darwinism: The Current Paradigm and the three pages following it are related Cosmic Ancestry webpages.
Viruses... is a related Cosmic Ancestry webpage. [Next-What'sNEW about HGT-Prev]
Tiny Tampa Bay Fish Key To Evolution is the subject of a reply from Stan Franklin, 6 Oct 2006.

1998, August 12: The paradigm continues to move toward lateral gene transfer as the primary driver of evolution. At a conference sponsored by the New York Academy of Sciences entitled "Molecular Strategies in Biological Evolution," June 27-29 in New York, thirty speakers addressed this topic. "The conventional explanation, that random changes accumulate one locus at a time, is unconvincing on both functional and probabilistic grounds...," said James Shapiro of The University of Chicago. And Ruth Hall of CSIRO/Molecular Science in Sydney talked about "...genes and groups of genes that move in and out of genomes like 'casettes'...." Although the transfer of genes by viruses has been known for fifty years, the importance of such phenomena in evolution is only now being acknowledged by mainstream neo-Darwinians.

In an eye-opening related 1997 paper, biologists from the University of Arizona write, "The number of well-documented cases in which [transposable element] sequences have been coopted by the host to provide a useful function is small but growing rapidly." And in August, 1998, another pair of biologists identified 755 genes that E. coli have acquired by horizontal transfer within the last 100 million years. This number is actually understated because acquired genes gradually mutate to resemble host genes, they say. Also, most acquired genes — but not all — are subsequently lost again. Furthermore, "The... horizontally transferred DNA... has included a large number of operons that could provide novel functions immediately on introduction."

Molecular Strategies in Biological Evolution, A New York Academy of Sciences Conference, June 27-29, 1998, The Rockefeller University, New York City.
Do Genomes Enhance Their Own Evolution? by Lynn Caporale, Issue 36, BioMedNet, August 7, 1998.
Kidwell, Margaret G. and Damon Lisch. "Transposable Elements as sources of variation in animals and plants," p 7704-7711 v 94, Proc. Natl. Acad. Sci. USA, July 1997. Presented at a colloquium held January 30-February 1, 1997, at the National Academy of Sciences Beckman Center in Irvine, CA. Abstract.
Lawrence, Jeffrey G. and Howard Ochman. "Molecular Archaeology of the Escherichia coli genome," p 9413-9417 v 95, Proc. Natl. Acad. Sci. USA, August 1998. Abstract.
Viruses... is a related Cosmic Ancestry webpage. [Next-What'sNEW about HGT-Prev]
Introns: A Mystery is a related Cosmic Ancestry webpage.

1998, July 28: Pioneering microbiologist Carl R. Woese says lateral gene transfer is more important than vertical inheritance at the earliest stages of life. In a sweeping new hypothesis he calls "genetic annealing," he speculates broadly about a "progenote era," although he says, "progenotes are not 'organisms' in any conventional sense." He concludes that the univeral ancestor was "a loosely knit, diverse conglomeration of primitive cells that evolved as a unit." Of course he does not endorse Cosmic Ancestry, but his rejection of the neo-Darwinian "last common ancestor" on Earth is a noteworthy development.

Woese, Carl "The universal ancestor," p 6854-6859 v 95, Proc. Natl. Acad. Sci. USA, June 9, 1998. Abstract.
Wade, Nicholas "Tree of Life Turns Out to Have Surprisingly Complex Roots," The New York Times, April 14, 1998.
Pennisi, Elizabeth "Genome Data Shake Tree of Life," p 672-674 v 280 n 5364, Science, 1 May 1998. Abstract.
The RNA World is a related Cosmic Ancestry webpage.
Viruses... is a related Cosmic Ancestry webpage. [Next-What'sNEW about HGT-Prev]
The Tree of Life is a related Cosmic Ancestry webpage.

1998, July 25: NASA scientist David S. McKay continues to see evidence for life on Mars in the ALH84001 meteorite. At the SPIE conference in San Diego on July 21, 1998, he defended this position against the latest criticism. Officially, he says we first need to identify reliable "biomarkers" with which to interpret the fossils. But with new support for the existence of fossilized and living nanobacteria, his case is already growing stronger.
McKay, David S.; Alexei Yu. Rozanov; Richard B. Hoover and Frances Westall. "Phosphate biomineralization of Cambrian microorganisms" [Abstract], doi:10.1117/12.319834, p 170-176, Instruments, Methods, and Missions for Astrobiology, Richard B. Hoover, Editor, Proceedings of SPIE vol. 3441, 6 Jul 1998.
MSNBC - Mars scientist addresses big questions, 3 Jul 1998.
MSNBC - The big question about life on Mars, by Alan Boyle, 3 Jul 1998.

Also, Gil Levin, who designed the "LR" life detecting experiment for the Viking missions, says there's liquid water on Mars. Liquid water is the one essential ingredient for life to live, and its presence would remove the last objection to his case for life on Mars today. Cameras on the two Viking landers, which worked from 1976 to 1979, occasionally photographed frost or snow on the ground. In a paper delivered in San Diego, July 20, Levin explained how the partial pressure of water vapor near the surface would permit the frozen water to liquify. Evidence from Russia of earthly microbes that could apparently live in Martian permafrost also strengthens the case for life there.
Levin, Gilbert V. and Ron L Levin. "Liquid water and life on Mars," [Abstract], doi:10.1117/12.319849, p 30-41, Instruments, Methods, and Missions for Astrobiology, Richard B. Hoover, Editor, Proceedings of SPIE vol. 3441, 6 Jul 1998.
"Reseacher presents case for liquid water on Mars," Florida Today Space Online, 21 Jul 1998.
Life on Mars! is a related Cosmic Ancestry webpage.