IV. Ecosmomics: A Survey of Animate Complex Network Systems
B. Our Own HumanVerse Genome Studies
Katz, Laura. Genomes: Epigenomics and the Future of Genome Sciences. Current Biology. 16/23, 2006. A Smith College biologist surveys and documents the nascent revolution which finds much more is going on beyond molecular genes. A definition for “epigenetics” might be the transmission of information not coded in DNA sequences from cell to daughter cell or from generation to generation. In this regard, as the quote broaches, instead of a direct route from genotype to phenotype, many intermediate functions get into the act, which changes everything.
Epigenomics encompasses genome-wide analyses of the growing list of epigenetic phenomena – such as DNA methylation, chromosome inactivation, non-Mendelian inheritance and programmed genome rearrangements – that are found across the tree of life. (R996)
Keller, Evelyn Fox. The Century of the Gene. Cambridge: Harvard University Press, 2000. A case against the limited, erroneous fixation on particulate genetic molecules and for an expanded, dynamical system of epigenetic expression. An extensive update "Beyond the Gene," with coauthor David Harel, can be found online at PloS One, (11/e1231, 2007), which argues for a new language and definition of a "gene."
Keller, Evelyn Fox. The Postgenomic Genome. Sarah Richardson and Hallam Stevens, eds.. Postgenomics: Perspectives on Biology after the Genome. Durham, NC: Duke University Press, 2015. In this chapter, the MIT science philosopher, historian, and feminist scholar, renown for her biography of the Nobel geneticist Barbara McClintock, provides a succinct review of the latest whole scale reimaginations of genome phenomena. As the quotes convey, no longer a passive registry, an holistic (epi)genomic organ acts in (re)active engagement with all manner of environmental influences. Other chapters such as The Polygenomic Organism by John Dupre and a summary by the editors well express this 2010s revolution.
Despite all the changes the gene concept has undergone, many of even the most recent formulations retain the view of these entities (and hence of genomes) as effectively autonomous formal agents, containing the blueprint for an organisms life – that is, all of the biological information needed to build and maintain a living organism. But I am claiming that current research in genomics leads to a different picture, and it does so by focusing attention on features that have been missing from our conceptual framework. In addition to providing information required for building and maintaining an organism, the genome also provides a vast amount of information enabling it to adapt and respond to the environment in which it finds itself, as indeed it must if the organism is to develop more or less normally and to survive more or less adequately. I am proposing that today’s genome, the postgenomic genome, looks more like an exquisitely sensitive reaction (or response) mechanism – a device for regulating the production of specific proteins in response to the constantly changing signals it receives from its environment – than it does the pregenomic picture of the genome as a collection of genes initiating causal chains leading to the formation of traits. (25)
Kepes, Francois. On the Transcription-based Solenoidal Model of Chromosomes: Epigenomics of Molecular Networks. Bioinformatics: Algorithms, Structures and Statistics Workshop. December 2005, . From a meeting which took place at the Ecole Polytechnique, Palaiseau, France, papers accessible via Google, e.g. Kepes+epigenomics. This certain work is one example deep in the literature of the growing recognition of “self-organizational principles” which serve to generate chromosome systems and cellular nuclear architecture. But such a major addition to and revision of evolutionary biology has not yet reached a paradigm shift, which this website hopes to facilitate.
Kirby, K. The Informational Perspective. BioSystems. 46/1, 1998. An overview of a special issue wherein 26 papers survey the programmatic aspects of self-organizing systems which appear with fractal similarity from biochemical reactions to the Internet.
Koonin, Eugene and Artem Novozhilov. Origin and Evolution of the Universal Genetic Code. Annual Review of Genetics. 51/45, 2017. In this chapter, the National Center for Biotechnology Information biologist and a North Dakota State University mathematician can explain, from our late vantage, how life’s genetic program commonly holds for every organism. An interplay of chance and necessity from relatively random to this default, most successful mode thus becomes evident.
The standard genetic code (SGC) is virtually universal among extant life forms. Although many deviations from the universal code exist, particularly in organelles and prokaryotes with small genomes, they are limited in scope and obviously secondary. The universality of the code likely results from the combination of a frozen accident, i.e., the deleterious effect of codon reassignment in the SGC, and the inhibitory effect of changes in the code on horizontal gene transfer. The structure of the SGC is nonrandom and ensures high robustness of the code to mutational and translational errors. (Abstract excerpt)
Krakauer, David. SFI @ 25: Very Few Cells Remain Unchanged. SFI Bulletin. Volume 24, 2009. A lead retrospective article about the Santa Fe Institute offers as an example of progress the nascent reinterpretation of genetic phenomena in terms of complex network systems. Such advances are then seen to contribute to its prime goal of the search for “general principles of complex, adaptive systems.” See also in this issue a longer article “The Complexity of the Gene Concept” by Krakauer and “Building Smart Groups” by Thomas Seeley
Traditionally, genetics was grounded in biochemistry, with a “disciplinary” approach of sequencing DNA and measuring gene activity. As the data increased, researchers catalogued the networks of interactions among molecules, and the genome became represented as a matrix of connections. At this point, questions of the stability and complexity of these networks became major concerns, forging a link with ecology, where researchers seek to understand the emergent properties of networks of interacting species. As the functional implications of these “ecological” patterns of activity started to surface, we began to see how the matrix of interactions could give rise to coherent patterns activity resulting from regular inputs to the system. Thus, the genome became a computational system, and questions of memory storage and information processing now dominate research. (1)
Kreplak, Jonathan, et al. A Reference Genome for Pea Provides Insight into Legume Genome Evolution. Nature Genetics. 51/9, 2019. Some 150 years after Gregor Mendel studied changes in pea plant height, pod and seed shape, flower position, color and more, forty-five geneticists posted in France, the Czech Republic, Australia, New Zealand, Germany, Canada, and the USA, a quite global group, post a comprehensive, graphic sequence.
Some 150 years after Gregor Mendel studied changes in pea plant height, pod and seed shape, flower position, color and more, forty-five geneticists posted in France, the Czech Republic, Australia, New Zealand, Germany, Canada, and the USA, a quite global group, post a comprehensive, graphic sequence.
Landenmark, Hanna, et al. An Estimate of the Total DNA in the Biosphere. PLoS Biology. Online July, 2015. With Duncan Forgan and Charles Cockell, University of Edinburgh, United Kingdom Centre for Astrobiology, researchers propose that it is now possible to quantify Earth’s flora and fauna endowment by way its genetic information content. The present biomass degree of “whole-organism genome analysis” is sufficient to be able to calculate a global value of “5.3 x 1031 megabases of DNA. It is said that such a novel view of natural and anthropogenic processes can aid their future sustainability. See also a NY Times notice on July 18 as Counting All the DNA on Earth by Rachel Nuwer.
Using available DNA sequencing and genome data, combined with large-scale surveys of biomass, we present an alternative way of quantifying and understanding biodiversity. This is accomplished by adopting an information view of biodiversity, in which the total amount of information in the biosphere is represented by the available amount of DNA. In this way, the biosphere can be visualised as a large, parallel supercomputer, with the information storage represented by the total amount of DNAand the processing power symbolised by transcription rates. In analogy with the Internet, all organisms on Earth are individual containers of information connected through interactions and biogeochemical cycles in a large, global, bottom-up network. (1)
Lane, Nick and William Martin. The Energetics of Genome Complexity. Nature. 467/929, 2010. University College London, and Heinrich-Heine University geneticists propose a novel explanation of how cellular life originally prospered and grew together beyond rudimentary bacteria.
All complex life is composed of eukaryotic (nucleated) cells. The eukaryotic cell arose from prokaryotes just once in four billion years, and otherwise prokaryotes show no tendency to evolve greater complexity. Why Not? Prokaryotic genome size is constrained by bioenergetics. The endosymbiosis that give rise to mitochondria restructured the distribution of DNA in relation to bioenergetic membranes, permitting a remarkable 200,000-fold expansion in the number of genes expressed. This vast leap in genomic capacity was strictly dependent on mitochondrial power, and prerequisite to eukaryote complexity: the key innovation en route to multicellular life. (Abstract, 929)
Ledford, Heidi. Riding the Crispr Wave. Nature. 531/136, 2016. A news report in a special section Crispr Everywhere about advances of this simple gene-splicing and editing technique with revolutionary potentials for genetic, medicinal and reproductive futures.
Levin, Michael and Christopher Martyniuk. The Bioelectric Code: An Ancient Computational Medium for Dynamic Control of Growth and Form. Biosystems. Online August, 2017. Tufts University and University of Florida biologists advance a broadly conceived project, with colleagues, to seek out and specify novel prescriptive means, agencies or informed forces which serve evolutionary organisms. The paper and task is imaginative and engaging as it elucidates more ways that life avails beside genes alone. As the second quote alludes, by way of computational analogies a doubleness of an independent, malleable program and resultant biological form and function can be perceived. See also, e.g., Endogenous Bioelectric Signaling Networks: Exploiting Voltage Gradients for control of Growth and Form by Leven, Giovanni Pezzulo and Joshua Finkelstein in Annual Review of Biomedical Engineering (19/353, 2017) and Physiological Inputs Regulate Species-Specific Anatomy During Embryogenesis and Regeneration by Kelly Sullivan, Maya Emmons-Bell, and Levin in Communicative & Integrative Biology (9/4, 2016) for more applications.
What determines large-scale anatomy? DNA does not directly specify geometrical arrangements of tissues and organs, and a process of encoding and decoding for morphogenesis is required. Moreover, many species can regenerate and remodel their structure despite drastic injury. The ability to obtain the correct target morphology from a diversity of initial conditions reveals that the morphogenetic code implements a rich system of pattern-homeostatic processes. Here, we describe an important mechanism by which cellular networks implement pattern regulation and plasticity: bioelectricity. All cells, not only nerves and muscles, produce and sense electrical signals; in vivo, these processes form bioelectric circuits that harness individual cell behaviors toward specific anatomical endpoints. We review emerging progress in reading and re-writing anatomical information encoded in bioelectrical states, and discuss the approaches to this problem from the perspectives of information theory, dynamical systems, and computational neuroscience. (Abstract)