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Biological evolution and technological innovation, while differing in many respects, also share common features. In particular, the implementation of a new technology in the market is analogous to the spreading of a new genetic trait in a population. Technological innovation may occur either through the accumulation of quantitative changes, as in the development of the ocean clipper, or it may be initiated by a new combination of features or subsystems, as in the case of steamships. Other examples of the latter type are electric networks that combine the generation, distribution, and use of electricity, and containerized transportation that combines standardized containers, logistics, and ships. Biological evolution proceeds, phenotypically, in many small steps, but at the genetic level novel features may arise not only through the accumulation of many small, common mutational changes, but also when distinct, relatively rare genetic changes are followed by many further mutations. New evolutionary directions may be initiated by, in particular, some rare combinations of regulatory sections within the genome. The combinatorial type of mechanism may not be a logical prerequisite for biological innovation, but it can be efficient, especially when novel features arise out of already highly developed systems. Such is the case with the evolution of general, widely applicable capabilities of the human brain. Hypothetical examples include the evolution of strategic thought, which encompasses multiple self-representations, cognition-based empathy, meta-levels of abstraction, and symbolic language. These capabilities of biologically modern man may have been initiated, perhaps some 150 000 years ago, by one or few accidental but distinct combinations of modules and subroutines of gene regulation which are involved in the generation of the neural network in the cerebral cortex. This hypothesis concurs with current insights into the molecular biology of the combinatorial and hierarchical facets of gene regulation that underlie brain development. A theory of innovation encompassing technological as well as biological development cannot per se dictate alternative explanations of biological evolution, but it may help in adding weight and directing attention to notions outside the mainstream, such as the hypothesis that few distinct genetic changes were crucial for the evolution of modern man.
Die Anwendung der Naturgesetze auf das verhaltenslenkende Gehirn widerspricht auf den ersten Blick der Freiheit des menschlichen Willens. Entsprechendes gilt für die Anwendung der Allmacht Gottes auf alle Vorgänge einschliesslich des menschlichen Verhaltens. Bei einem zweiten Blick auf diese scheinbar so konsequenten Gedankengänge erkennt man aber Verstrickungen in Selbstbezüglichkeiten, die jeweils Mehrdeutigkeiten und Grenzen unseres möglichen Wissens implizieren. Diese zeigten sich schon in Gödels Grenzen mathematisch-logischer Entscheidbarkeit ebenso wie in Heisenbergs Unbestimmtheitsgesetzen der Quantenphysik. Entsprechende Grenzen könnte es für eine vollständige physikalisch begründete Theorie unseres Bewußtseins und damit auch des menschlichen Willens geben - schliesslich würde sie Bewußtsein von Bewußtsein implizieren. In der theologischen Gedankenlinie wiederum kann sich die Allmacht Gottes auch auf die Allmacht selbst richten, indem sie eine weise naturgesetzliche Ordnung ohne ständige göttliche Eingriffe begr ündet und darin den Menschen als Freien will - so etwa sahen es freiheitsfreundliche unter den Theologen wie Eriugena und Cusanus. Mein Essay weist darauf hin, dass selbst bei so verschiedenen Denkweisen wie den naturwissenschaftlichen und theologischen jeweils analoge Selbstbezüglichkeiten auftreten, die unsere Erkenntnis begrenzen.
Unsere Kulturfähigkeit ist ein Ergebnis der biologischen Evolution der Spezies “Mensch”; die einzelne Kultur selbst jedoch ist ein Produkt gesellschaftlicher Entwicklungen, Differenzierungen und Traditionen. Der Kulturvergleich zeigt uns erhebliche Spielräume für Ausprägungen von Gemeinsinn. Da dessen Aktivierung wesentlich zur Lebensqualität einer Gesellschaft beiträgt, sind Versuche einer realistischen Einschätzung kultureller Gestaltungsspielräume in dieser Hinsicht sinnvoll. Sie sind nicht zuletzt durch die biologischen Grund- und Randbedingungen der Spezies Mensch gegeben und begrenzt, zumal hinsichtlich von Anlagen zu altruistischem und kooperativem Verhalten. Während bis vor kurzem Soziobiologen und Sozialwissenschaftler oft wenig Neigung zu gegenseitigem Verständnis zeigten, zumal manche Biologen relativ extreme Theorien über genetisch angelegte egoistische Verhaltensanlagen vertraten, verstehen sich neuere, durch die Spieltheorie beeinflusste und sehr allgemeine psychische Disposition betonende Linien soziobiologischen Denkens dazu, auch ausgesprochen freundliche Eigenschaften unserer Spezies zu erklären und zu begründen. Sie kommen sozialwissenschaftlichen Bestrebungen entgegen, zum Beispiel in Zusammenhang mit Theorien begrenzt rationalen Verhaltens, in denen die Fairness eine wesentliche Rolle spielt. Besondere Aufmerksamkeit verdienen in diesem Zusammenhang die biologisch angelegte Fähigkeit zu kognitionsgestützter Empathie sowie die fragile Anlage “Vertrauensbereitschaft”, von denen die Effizienz und das Wohlbefinden in einer Gesellschaft wesentlich abhängen. Insgesamt kann eine - keineswegs unkritische - Beachtung evolutionsbiologischer Aspekte menschlicher Verhaltensdispositionen zu einer realistischen Einschätzung der knappen Ressource “Gemeinsinn” beitragen. Sie ist in Grenzen durchaus ein auch in der Natur des Menschen angelegtes Potential. Dies ist jedoch - unter Beachtung eben dieser Grenzen - behutsam zu aktivieren. Moralische Überforderungen, welche die natürlichen Anlagen des Menschen missachten, sind kontraproduktiv.
Within the sedimentation diagram of infective RNA preparations isolated from Tobacco Mosaic Virus, undegraded molecules form a sharp peak with a molecular weight corresponding to the total RNA content of the virus particle. Degradation kinetics by ribonuclease is of the linear, single-target type, indicating that the RNA is single-stranded. The intact RNA of a virus particle thus forms one big single-stranded molecule. Quantitative evaluation of the effect degradation by RNA-ase on the infectivity of the RNA shows that the integrity of the entire molecule is required for its biological activity.
The generation of viral mutants in vitro was demonstrated by treatment of the isolated RNA of Tobacco Mosaic Virus by nitrous acid. This agent causes deaminations converting cytosine into uracil, and adenine into hypoxanthine. Our assay for mutagenesis was the production of local lesions on a tobacco variety on which the untreated strain produces systemic infections only. A variety of different mutants are generated in this way. Quantitative analysis of the kinetics of mutagenesis leads to the conclusion that alteration of a single out of the 6000 nucleotides of the viral RNA is sufficient for causing a mutation.
Aggregates of previously isolated cells of Hydra are capable, under suitable solvant conditions, of regeneration forming complete animals. In a first stage, ecto- and endodermal cells sort out, producing the bilayered hollow structure characteristic of Hydra tissue; thereafter, heads are formed (even if the original cell preparation contained no head cells), eventually leading to the separation of normal animals with head, body column and foot. Hydra appears to be the highest type of organism that allows for regeneration of the entire structure from random cell aggregates. The system is particularly useful for studying cell interactions, tissue polarity, pattern formation, and cell differentiation.
Ancient Greek philosophers were the first to postulate the possibility of explaining nature in theoretical terms and to initiate attempts at this. With the rise of monotheistic religions of revelation claiming supremacy over human reason and envisaging a new world to come, studies of the natural order of the transient world were widely considered undesirable. Later, in the Middle Ages, the desire for human understanding of nature in terms of reason was revived. This article is concerned with the fundamental reversal of attitudes, from “undesirable” to “desirable”, that eventually led into the foundations of modern science. One of the earliest, most ingenious and most interesting personalities involved was Eriugena, a theologian at the Court of Charles the Bald in the 9th century. Though understanding what we call nature is only one of the several aspects of his theological work, his line of thought implies a turn into a pro-scientific direction: the natural order is to be understood in abstract terms of ‘primordial causes’; understanding nature is considered to be the will of God; man encompasses the whole of creation in a physical as well as a mental sense. Basically similar ideas on the reconciliation of scientific rationality and monotheistic religions of revelation were conceived, independently and nearly simultaneously, by the Arab philosopher al-Kindi in Bagdad. Eriugena was more outspoken in his claim that reason is superior to authority. This claim is implicit in the thought of Nicholas of Cusa with his emphasis on human mental creativity as the image of God’s creativity; and it is the keynote of Galileo’s ‘Letter to the Grand Duchess Christina’ some 800 years later, the manifesto expressing basic attitudes of modern science. This article in English is based on the monography (in German): A. Gierer “Eriugena, al-Kindi, Nikolaus von Kues - Protagonisten einer wissenschaftsfreundlichen Wende im philosophischen und theologischen Denken”, Acta Historica Leopoldina 29 (1999), Barth Verlag in MVH Verlage Heidelberg, ISBN: 3-335-00652-6
Upon separation of the protein from the nucleic acid component of tobacco mosaic virus by phenol, using a fast and gentle procedure, the nucleic acid is infective in assays on tobacco leaves. A series of qualitative and quantitative control experiments demonstrates that the biological activity cannot depend on residual proteins in the preparation, but is a property of isolated nucleic acid which is thus the genetic material of the virus.
Applying mild methods of preparation, part of the ribosomes of rabbit reticulocytes are found in aggregates (later called polyribosomes) of up to six ribosomal units. Upon treatment with RNA-ase, they desintegrate into single ribosomes. The fast-sedimenting aggregates are found to be more active in protein synthesis in terms of incorporation of radioactive amino acids, whereas the single ribosomes are more receptive to stimulation by the artificial messenger RNA poly-U. The findings indicate that the linkage of ribosomes into aggregates is due to the messenger RNA. They support a tape-reading mechanism of protein synthesis whereby growth of the peptide chain is accompanied by shifting the active site of the ribosome from one coding group of nucleotides of the messenger RNA to the next.
The paper addresses the formation of striking patterns within originally near-homogenous tissue, the process prototypical for embryology, and represented in particularly puristic form by cut sections of hydra regenerating a complete animal with head and foot. Essential requirements are autocatalytic, self-enhancing activation, combined with inhibitory or depletion effects of wider range - “lateral inhibition”. Not only de-novo-pattern formation, but also well known, striking features of developmental regulation such as induction, inhibition, and proportion regulation can be explained on this basis. The theory provides a mathematical recipe for the construction of molecular models with criteria for the necessary non-linear interactions. It has since been widely applied to different developmental processes.