IV. Ecosmomics: A Survey of Animate Complex Network Systems
B. Our Own HumanVerse Genome Studies
Olsen, Peter, et al, eds. Next Generation Systematics. Cambridge: Cambridge University Press, 2016. As the blurb notes, this volume 78 of the Systematics Association series considers how their phylogenetics endeavors (second quote) can be advanced by the latest sequencing abilities. Some chapters are Systematics in the Age of Genomics by Antonis Rojas, and The Role of NGS for Integrative Approaches in Evolutionary Biology by Ralf Sommer. The edition is another instance of nature’s every aspect gaining a genetic essence
We live in an age of ubiquitous genomics. Next generation sequencing (NGS) technology, both widely adopted and advancing at pace, has transformed the data landscape, opening up an enormous source of heritable characters to the comparative biologist. Its impact on systematics, like many other fields of biology, has been felt throughout its breadth: from defining species boundaries to estimating their evolutionary histories. This volume examines the broad range of ways in which NGS data are being used in systematics and in the fields that it underpins, from biodiversity prospecting to evo-devo. Experts in their fields draw on contemporary case studies to demonstrate state-of-the-art applications of NGS data. These, along with novel analyses, comprehensive reviews and lively perspectives, are combined to produce an authoritative account of contemporary issues in systematics that have been impacted by the adoption of NGS (Publisher).
Pagel, Mark. Rise of the Digital Machine. Nature. 452/699, 2008. In this note, the University of Reading biologist cites a common affinity between genomes and language. Our speech might thus be genetic in kind, while the molecular code can appear as a written text. In each parallel case, the total number of words or DNA genes is not important but how they are ‘grammatically’ used or regulated in a complex adaptive system. From our vantage I add, this rise of evolutionary information might be seen to proceed from analogue to digital (alphabetic) and on a nascent bicameral synthesis of both modes. What kind of a Universe evolves its own Reader? Are ‘we the people’ in some way acting as ‘genes’ trying to learn and continue the cosmic genetic message?
Human societies and multicellular organisms share a puzzling feature. They seem to be under-specified. Our societies depend on many more interactions among group members than there are members. Multicellular organisms have many more parts, and connections among those parts, that they have genes. This points to a principle of regulation in the evolution of such complex adaptive systems: complexity areses not from the number of genes or actors but from how those elements are expressed or deployed. (699) Deep down, language may be just the latest form of gene regulation – the voice of our genes. Information management, not lats of parts, is the key to complexity. (699)
Pah, Adam, et al. Use of a Global Metabolic Network to Curate Organismal Metabolic Network. Nature Scientific Reports. 3/1695, 2013. Via Google, the word Curate has dual meanings – “a person invested with the care or cure of souls,” or “to organize, sort, arrange, such as a museum.” A “Curator” is an overseer or caretaker. As the quotes explain, with Roger Guimera, A. M. Mustoe, and Luis Amaral, Northwestern University systems biologists propose a novel sophistication to further limn and parse complex genomes. As scientists proceed with this literacy project, as if “cosmic curators,” we seem to fulfill a phenomenal role as an intended agency by which a genesis uniVerse tries to consciously read its own genetic code.
The difficulty in annotating the vast amounts of biological information poses one of the greatest current challenges in biological research. The number of genomic, proteomic, and metabolomic datasets has increased dramatically over the last two decades, far outstripping the pace of curation efforts. Here, we tackle the challenge of curating metabolic network reconstructions. We predict organismal metabolic networks using sequence homology and a global metabolic network constructed from all available organismal networks. While sequence homology has been a standard to annotate metabolic networks it has been faulted for its lack of predictive power. We show, however, that when homology is used with a global metabolic network one is able to predict organismal metabolic networks that have enhanced network connectivity. Additionally, we compare the annotation behavior of current database curation efforts with our predictions and find that curation efforts are biased towards adding (rather than removing) reactions to organismal networks. (Abstract)
Pearson, Helen. What is a Gene? Nature. 441/399, 2006. The burst of genome sequencing is causing a major revision in the definition of what a gene is. No longer beads on a string, it is more like a DNA information package, which involves RNA, and whose protein codes have no clear beginning or end.
Piatogorsky, Joram. Gene Sharing and Evolution. Cambridge: Harvard University Press, 2007. The Chief of the Laboratory of Molecular and Developmental Biology, National Eye Institute, National Institutes of Health, quite engaged at the forefront of genetic research, discusses the on-going revision and redefinition of the nature of genes and their many activities. As an example of original multitasking, one gene can produce a polypeptide (a protein string of amino acids) with several optional biochemical functions. These novel insights and properties contribute to the systems biology project to articulate such contextual dynamic networks that discrete genes are contained within.
Although gene sharing refers specifically to multiple molecular uses of an individual polypeptide, the modern “gene” in gene sharing is an interactive, differentially expressed gene that challenges the investigator to see in how many ways it can enlarged through the functions of its polypeptide rather that how it might be subdivided into an elementary unit, as was the goal of investigators in the classical and neoclassical concepts of the gene. (53) Networks transform molecular biology to “modular” biology and link the rules of biology to many different disciplines, including statistical physics, engineering, the Internet, ecosystems, and social interactions. (196)
Pigliucci, Massimo. Genotype-Phenotype Mapping and the End of the ‘Genes as Blueprint’ Metaphor. Philosophical Transactions of the Royal Society B. 365/557, 2010. A paper in a dedicated issue on “Phenotypic Plasticity in Development and Evolution.” As long as an evolutionary burden remains that nothing beyond accident and selection is going on, a grand revision, here actually added to by one of the main players, (see Pigliucci & Muller, eds. Evolution – the Extended Synthesis, May 2010 from MIT Press) can not yet be appreciated. We are advised once more that the textbook stage of “bean-bag genetics” is over, superseded by nonlinear developmental encodings between information and individual in the guise of robust modular networks with “computational” activities.
Portin, Petter. The Elusive Concept of the Gene. Hereditas. 146/3, 2009. In a paper noted by the journal as the most cited, a University of Turku, Finland geneticist provides a succinct summary, as the three quotes aver, of the 21st century revolution from molecular determinations to “interlaced networks” across nested scales stretching in a reciprocal way from genome to organism and environment. A “gene” is no longer a separate, fixed entity, rather entire genotypes are complicated webworks of complex, heritable components. Nucleotide sequences thus become “quantitative collections of binary information” applied in a variety of instances, depending on the organismic context. And to add, while reading about such genes and genomes, one is struck by their similarity to words in a sentence and paragraph, with a meaning dependent on the message being conveyed.
In recent years geneticists have witnessed many significant observations which have seriously shaken the traditional concept of the gene. These specifically include the facts that (1) the boundaries of transcriptional units are far from clear; in fact, whole chromosomes if not the whole genome seem to be continuums of genetic transcription, (2) many examples of gene fusion are known, (3) likewise many examples of so-called encrypted genes are known in the organelle genomes of microbial eukaryotes and in prokaryotes, and (4) in addition to the structure of the gene, its functional status can also be inheritable, and, further, (5) epigenetic extra-genomic modes of inheritance, called genetic restoration, seem to be a rather common phenomenon, meaning that organisms can sometimes rewrite their DNA on the basis of RNA messages inherited from generations past. (Abstract)
Portin, Petter and Adam Wilkins. The Evolving Definition of the Term “Gene.”. Genetics. 205/4, 2017. University of Turku, Finland and Humboldt University, Germany biologists (search each) first survey past takes on this “unit of inheritance” from before and after the 1950s molecular DNA helix and through to major 21st century revisions. In this current phase which gives equal import to “gene regulatory networks (GRN),” a new sense of nodal nucleotide and interlinked reciprocities, aka genome-wide association studies (GWAS), has come forth. As the quote alludes, we may view one more exemplary presence of a universal complementarity of particulate and integrative modes.
The conceptual consequences of viewing individual genes not as autonomous actors, but as interactive elements or outputs of networks are profound. For one thing, it becomes relatively easy to think about the nature of genetic background effects in terms of the structure of gene regulatory nets. While much of the thinking of the 20th century about genes was based on the premise that the route from gene to phenotype was fairly direct, and often deducible form the nature of the gene product, the network perspective envisages far more complexity and indirectness of effects. In general, the path from particular genes to specific phenes is long, and the role of many gene products seems to be the activation or repression of the activities of other genes. (1360)
Qui, Jane. Unfinished Symphony. Nature. 441/143, 2006. The codons in our now sequenced genome are orchestrated by an overlaying “epigenetic” code, which researchers are just tuning in to.
Rando, Oliver and Kevin Verstrepen. Timescales of Genetic and Epigenetic Inheritance. Cell. 128/4, 2007. One cannot underestimate the scope of this revolution in our understanding of heredity and evolution. While classic theory says phenotypic variety arises from random mutations independent of selective pressures, the latest research finds that organisms have evolved mechanisms to influence the timing or genomic location of heritable variation. In a revival of “directed mutagenesis” from the 1980’s, cells seem to exhibit a biased behavior in favor of successful variants to changing environmental stresses. By these lights, the views of Darwin, and especially of Lamarck, that life evolves in a self-guiding manner so as to maximize its survivability are said to deserve new notice. (See also Bernstein, Bradley, et al. The Mammalian Epigenome in the same issue)
We now finally turn to the idea that organisms may orchestrate specific, nonrandom heritable changes in themselves in response to appropriate conditions. (665)
Rea, Thomas, et al. Complex Adaptive Systems and the Genetic Analysis of Plasma HDL-Cholesterol Concentration. Perspectives in Biology and Medicine. 49/4, 2006. Together with Christine Brown and Charles Sing, all from the University of Michigan, another example of the conceptual shift in genetics whereof the old gene model of isolated particles is set aside in favor of dynamically self-organizing genomic systems. Rather than deterministic programs, typical CAS features of multiple interacting agents (apolipoproteins, receptor and membrane proteins, the genes that encode them, and various lipid classes), which form modular domains, and nonlinearly emergent phenotypes are being found. The authors conclude that a new, integrative, humanist ‘natural philosophy’ is implied.
On the other hand, living organisms are better understood as complex adaptive systems characterized by multiple participating agents, hierarchical organization, extensive interactions among genetic and environmental effects, nonlinear responses to perturbation, temporal dynamics of structure and function, distributed control, redundancy, compensatory mechanisms, and emergent properties. (491)
Richards, Stephen. It’s More than Stamp Collecting: How Genome Sequencing can Unify Biological Research. Trends in Genetics. 31/7, 2015. In accord with how 2010s genome reading capabilities are wholly revising paleontology studies, a Baylor College of Medicine, Human Genome Sequencing Center, geneticist proposes to advance the life sciences by a similar emphasis and synthesis. Just as paleogenomics is achieving, scientists are beginning to employ these novel potentials across the Metazoan flora and fauna kingdoms. Going forward, we ought to recognize and employ this revolutionary approach via comparative orthologies and ontologies from arthropods to anthropopods (my word). With proper foresight, the establishment of a sufficiently complete spatial and temporal genome reference library should be of great value for ecological sustainability.
The availability of reference genome sequences, especially the human reference, has revolutionized the study of biology. However, while the genomes of some species have been fully sequenced, a wide range of biological problems still cannot be effectively studied for lack of genome sequence information. Here, I identify neglected areas of biology and describe how both targeted species sequencing and more broad taxonomic surveys of the tree of life can address important biological questions. I enumerate the significant benefits that would accrue from sequencing a broader range of taxa, as well as discuss the technical advances in sequencing and assembly methods that would allow for wide-ranging application of whole-genome analysis. Finally, I suggest that in addition to ‘big science’ survey initiatives to sequence the tree of life, a modified infrastructure-funding paradigm would better support reference genome sequence generation for research communities most in need. (Abstract)