9 results found.
... Science Frontiers ONLINE No. 139: Jan-Feb 2002 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects How The Genome's Message Can Be Altered Our genomes (complements of genes) can no longer be called sets of instructions like those in a computer program. Demonstrating the veracity of this statement are the following three quotations. Increasingly, a picture of interactivity and multifunctionality among genes is emerging that precludes such a simple one-to-one mapping. Furthermore, the genome can exhibit considerable flexibility to adapt when the expression of a particular gene fails, and the interpretation of a mutant phenotype [life form] is also less trivial than it may seen. "Not only are behavioural phenotypes very sensitive to non-genetic influences," writes [R .] Greenspan, "but also the highly interconnected network of the nervous system sets up an additional layer of complexity between the gene and the realization of the phenotype." (Ref. 1) Many genes code for multiple variants of the same protein. And many proteins are modified by adding sugar molecules, which play a big role in determining where proteins go and what they do. What's more, different proteins can join together to carry out completely new functions. (Ref. 2) A group of French biologists, led by Francois Jacob and Jacques Monod showed that the gene's boundaries are fuzzier than had been thought and that genes are not restricted to chromosomes. Recently, biologists have found genes within genes, overlapping genes, and DNA sequences that ...
Terms matched: 1 - Score: 39 - 15 May 2017 - URL: /sf139/sf139p05.htm
... 11: Summer 1980 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Hierarchies Of Evolution All organisms from man to mouse to amoeba are merely DNA's way of manufacturing still more DNA -- so goes the modern ramification of molecular biology and the Genetic Code. In other words, DNA and genes are selfish, and ultimate parasites, directing the evolution of life only to maximize the production of DNA. This theme is not the subject of this paper by Doolittle and Sapienza. Rather, they wonder about those nonsense DNA sequences that do not code for protein. The presence of these "useless" bits of genetic material is often explained in terms of gene "expression." Emphasis is always on maximizing the "fitness" of the organism (phenotype). Perhaps this seemingly excess genetic material actually maximizes the fitness (survivability) of the DNA itself. Evolution thus occurs at DNA and gene (genome) levels, despite what transpires at the organism (phenotype) level. (Doolittle, W. Ford, and Sapienza, Carmen; "Selfish Genes, the Phenotype Paradigm and Genome Evolution," Nature, 284:601, 1980.) Comment. We know that mitochondria and chloroplasts have their own genetic material; evolution may be occurring at this level, too, independent of pressures for change on the organisms. Waxing speculative, may there not be other hierarchies where systems are trying to maximize their own survivability, even at molecular, atomic, and subatomic levels? Don't laugh! Is not all life implicitly encoded ...
Terms matched: 1 - Score: 36 - 15 May 2017 - URL: /sf011/sf011p04.htm
... Science Frontiers ONLINE No. 41: Sep-Oct 1985 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Evolution's motor runs fast and quietly M. Kimura has been promulgating what he terms The Neutral Theory of Evolution. He concludes that "the most prev-alent evolutionary changes that have occurred at the molecular level, that is in the genetic material itself, since the origin of life on Earth are those that have been caused by random genetic drift rather than by positive Darwinian selection." Kimua maintains and can experimentally prove to some extent that the genetic material of all organisms changes rapidly and constantly. The genes change much more rapidly than scientists believed just a few years ago. We observe few if any changes at the phenotype level (organism morphology) because the overwhelming majority of these changes are neutral. They confer no significant advantage or disadvantage on the organism. In fact, Kimura and others have demonstrated that the fastest molecular evolution occurs in the least important genes. It is fastest of all in the pseudogenes or dead genes, which seem to have no discernable functions. In other words, the genetic engine is running, but the gears are in neutral! In Kimura's thinking, these molecular changes may eventually become important at the phenotype level if the environment changes or there is some other destabilizing influence. Kimura is the author of the 1983 book The Neutral Theory of Molecular Evolution. Although Kimura has some experimental support, his theory is not widely accepted. (Motoo Kimura; "The Neutral Theory of Molecular ...
Terms matched: 1 - Score: 24 - 15 May 2017 - URL: /sf041/sf041p10.htm
... Science Frontiers ONLINE No. 117: May-June 1998 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects The Unread Biotic Message We have been selling ReMine's book The Biotic Message in which he asserts that life itself is a message of transcendental nature. Every bacterium and human is a cosmic statement. Shifting from the macroscopic to the microscopic (phenotype to genotype), we recall that all macroscopic "statements" are really expressions of DNA -- the genetic code. But when we examine DNA, we find that only about 3% of the DNA in human cells codes for protein manufacture. The remaining 97% is termed "nonsense" or "junk" DNA. But there may actually be sense in nonsense DNA. Statistical analysis of nonsense-DNA "words" (3 -8 bases long) reveals considerable redundancy. Long stretches of nonsense DNA are definitely not random. In fact, the structure of nonsense DNA resembles that of language. The coding or "sense" DNA, on the other hand, lacks this language structure. The implication is that coding and nonsense DNAs carry different kinds of messages. The former consists simply of blueprints; the latter is couched in a language that we have not yet learned to read. (Flan, Faye; "Hints of a Language in Junk DNA," Science, 266:1320, 1994.) Comment. On the microscopic level, we can read only 3% of the biotic message! From Science Frontiers #117, MAY-JUN 1998 . 1998 ...
Terms matched: 1 - Score: 14 - 15 May 2017 - URL: /sf117/sf117p04.htm
... for example, as expressed in the illustration. A key connecting character here is mutual warmbloodedness. The shifting of a few lines in a cladogram may seem trivial to the nonbiologist, but saying that man is more closely related to a chicken than a lizard is pretty controversial stuff to the conservative evolutionist. DNA analysis supports the contention that humans are more closely related to birds than reptiles. Paleontological evidence, however, supports the opposite view. The fight rages on. (Benton, Mike; "Is a Dog More Like a Lizard or a Chicken?" New Scientist, p. 18, August 16, 1984.) Comment. It all seems to boil down to morphology in the end. Which is a more faithful record of the development of life through the long eons, the phenotype (what the organism looks like) or the genotype (what the DNA looks like)? This may be a dangerous simplification. Why? Because life just may be shaped by more than DNA. Standard evolution cladogram (left). Cladogram based only on characters (right). The numbers are millions of years before present. From Science Frontiers #36, NOV-DEC 1984 . 1984-2000 William R. Corliss ...
Terms matched: 1 - Score: 14 - 15 May 2017 - URL: /sf036/sf036p09.htm
... Science Frontiers ONLINE No. 82: Jul-Aug 1992 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Can you guess where this quotation comes from?THE GRADUALIST'S DILEMMA "The basic article of faith of a gradualist approach is that major morphological innovations can be produced without some sort of saltation. But the dilemma of the New Synthesis is that no one has satisfactorily demonstrated a at the population genetic level by which innumerable very small phenotypic changes could accumulate rapidly to produce large changes: a process for the origin of the magnificently improbable from the ineffably trivial. This leads to skepticism about the microevolutionary approach. Perhaps, as Waddington put it: 'the real guts of evolution -- which is, how do you come to have horses and tigers, and things -- is outside the mathematical theory.'" Did you guess a creationist publication? Sorry! (Thomson, Keith Stewart; "Macroevolution: The Morphological Problem," American Zoologist, 32:106, 1992.) (And just the other day, we read that evolution was a proven fact!) From Science Frontiers #82, JUL-AUG 1992 . 1992-2000 William R. Corliss ...
Terms matched: 1 - Score: 13 - 15 May 2017 - URL: /sf082/sf082b11.htm
... sequence is repeated a million times in each cell. (Stebbins, G. Ledyard, and Ayala, Francisco J.; "The Evolution of Darwinism," Scientific American, 253:72, July 1985.) Comment. Why so much redundance? Or is there some purpose for this excess genetic material that we haven't yet descried? The "useless" sequences may merely be left over from ancient gene shufflings; or they may be awaiting future calls to action. The above tidbits come from a long review article that is generally supportive of the modern theory of evolution. (Would it have been printed in Scientific American if it weren't ?) The article also treats the Neutral Theory of Evolution, noting that this theory still depends upon natural selection operating at the phenotype (organism) level. From Science Frontiers #41, SEP-OCT 1985 . 1985-2000 William R. Corliss ...
Terms matched: 1 - Score: 13 - 15 May 2017 - URL: /sf041/sf041p11.htm
... Science Frontiers ONLINE No. 24: Nov-Dec 1982 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Why cancer?" However, the most formidable obstacle to the successful treatment of disseminated cancer may well be the fact that the cells of a tumor are biologically heterogeneous. This phenotypic diversity, which allows selected variants to develop from the primary tumor, means not only that primary tumors and metastases can differ in their responses to treatment but also that individual metastases differ from one another. This diversity can be generated rapidly even when the tumors originate from a single transformed cell." (Fidler, Isaiah J., and Hart, Ian R.; "Biological Diversity in Metastatic Neoplasma: Origins and Implications," Science, 217:998, 1982.) Comment. The ability of single cancer cells to multiply into different kinds of cells, as well as propagate throughout an organism, seems to betoken an insidious biological entity, whose origin and purpose (? ) we have hardly begun to comprehend. How could cancer have evolved if it leaves no progeny? How could natural selection leave us so susceptible to cancer? Reference. The many enigmas of cancer are covered in categories BHH23-35 in our Catalog: Biological Anomalies: Humans II. For information on this book, visit: here . From Science Frontiers #24, NOV-DEC 1982 . 1982-2000 William R. Corliss ...
Terms matched: 1 - Score: 13 - 15 May 2017 - URL: /sf024/sf024p08.htm
... of Anesthesia Evolution of Menstruation Fetal Growth Correlated with Solar Activity Evolution of Sex Purpose of Life after Menopause Decline in Sperm Counts Fetus Signals Timing of Birth How Embryo Development Is Controlled and Effected Cycles in Autistic Births Rhythms in Growth Evolution of Lactose Tolerance Twins and Occurrence of Nightmares Timing of the End of Sleep BHG HUMAN GENETICS BHG1 Human Chromosomes Less Evolved Than Ape Chromosomes BHG2 The Presence of Introns in Human Chromosomes BHG3 Human Chromosomes Lack the "Baboon Marker" BHG4 Y-Chromosome Analysis Suggests First Humans Were Pygmies BHG5 Human and Ape Chromosome Numbers Differ BHG6 Identical Twins May Have Different Genomes BHG7 Gene Imprinting: Parental Influence on Genes BHG8 The Accentuation of Inherited Traits in Succeeding Generations BHG9 Higher Variability of Mitochondrial DNA in Subsaharan Africans BHG10 Mitochondrial DNA Evolves Much Faster Than Nuclear DNA BHG11 Disparity between Human and Ape Phenotypes and Genotypes BHG12 Chimpanzee Mitochondrial DNA More Diverse Than That of Humans BHG13 Human Mitochondria Radically Different from Those of Other Organisms BHG14 Paternal Mitochondrial DNA can Be Inherited BHG15 African Nuclear DNA Is Distinct from That of Other Populations BHG16 Chromosome Banding Analysis Incompatible with DNA Analysis BHG17 Involucrin Analysis Conflicts with Mitochondrial DNA Analysis BHG18 Human Molecular Clocks Run More Slowly Than Those of Apes BHG19 Absence of Transitional Forms of Cytochrome C DNA Analysis and the Origin of Modern Populations High Deleterious Mutation Rates in Hominids Fetal DNA in Mother's Blood Epigenetic Inheritance Unique Human Lack of Retroviruses Neanderthal mtDNA Different Persistence of Cystic Fibrosis Gene Humanity's "Missing" Mutations Persistence of ITD Gene Overall Human Mutation Rates Very Low "Junk" Genes and Human Evolution Curious Genetic Homologies HIV-Like Gene in Human DNA BHH HEALTH BHH1 Health ...
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