ARN ID Update
Casey Luskin of the Discovery Institute gives his take on the debate. "Ham talked about some science here and there, but almost all of what he said focused on trying to support a young earth viewpoint. Since he's not a scientist, the great majority of his arguments amounted - over and over again - to "Because the Bible says so." Nye's main argument was, "Because the evidence says so," and he cited a lot of reasonable evidence for an old earth. While Ham did make a few effective points that you don't have to accept evolution to do good science, the compelling scientific evidence for design in nature got skipped over".
Redundancy in the genetic code has long been recognised. Most amino acids can be specified in multiple ways (2-6 synonymous codons). More recently, it has also become known that synonymous codons are non-random, stimulating thought as to why this should be (see here). Since codon usage biases characterise both prokaryotic and eukaryotic genomes, is it possible that they are accidents of evolutionary history? This seems to be ruled out by pervasive evidences of conservation. Since the biases are not removed by mutations, it is inferred that "observed codon preferences in mammalian genomes [. . .] appear to be under selection" (p.1367.) Such a conclusion is reached by deduction from evolutionary theory. If specific (synonymous) codons do not matter when manufacturing proteins, is it possible they are relevant to the regulation of genetic processes? Since there is a presumption favouring simplicity in the minds of most geneticists, this research question has only recently been taken up. There are many synonymous codons when coding for proteins, but are they synonymous if they are also coding regulatory instructions?
"Genomes also contain a parallel regulatory code specifying recognition sequences for transcription factors (TFs), and the genetic and regulatory codes have been assumed to operate independently of one another and to be segregated physically into the coding and noncoding genomic compartments. However, the potential for some coding exons to accommodate transcriptional enhancers or splicing signals has long been recognized." (p.1367)
The challenge of the Human Genome Project has given way to searching for an understanding of multiple overlapping genetic codes. (source here)
With the availability of large amounts of genome data, it is possible to test many hypotheses relevant to the functionality of DNA sequences. The data set used is impressive:
"To define intersections between the regulatory and genetic codes, we generated nucleotideresolution maps of TF occupancy in 81 diverse human cell types using genomic deoxyribonuclease I (DNaseI) footprinting. Collectively, we defined 11,598,043 distinct 6- to 40-base pair (bp) footprints genome-wide (~1,018,514 per cell type), 216,304 of which localized completely within protein-coding exons (~24,842 per cell type). Approximately 14% of all human coding bases contact a TF in at least one cell type (average 1.1% per cell type), and 86.9% of genes contained coding TF footprints (average 33% per cell type)." (p.1367)
A summary of the main findings of the research team is provided in a Perspectives essay by Weatheritt and Babu. The hypothesis of two co-existing codes is fully justified by the evidence. According to the press release: "scientists were stunned to discover that genomes use the genetic code to write two separate languages."
"How widespread is the phenomenon of "regulatory" codes that overlap the genetic code, and how do they constrain the evolution of protein sequences? Stergachis et al. address these questions for the transcription factor-binding regulatory code. They use deoxyribonuclease I (DNase I) footprinting to map transcription factor occupancy (a protein bound to DNA can protect that region from enzymatic cleavage) at nucleotide resolution across the human genome in 81 diverse cell types. The authors determined that ~14% of the codons within 86.9% of human genes are occupied by transcription factors. Such regions, called "duons", therefore encode two types of information: one that is interpreted by the genetic code to make proteins and the other, by the transcription factor-binding regulatory code to influence gene expression. This requirement for transcription factors to bind within protein-coding regions of the genome has led to a considerable bias in codon usage and choice of amino acids, in a manner that is constrained by the binding motif of each transcription factor." (p.1325)
Weatheritt and Babu go further. They suggest a general principle: that redundancy in the genetic code opens the door for, not one, but many regulatory codes that can operate within protein-coding regions of the genome. One research question of the future is: how many overlapping codes can be tolerated by the genetic code?
"This "binding" code joins other "regulatory" codes that govern chromatin organization, enhancers, mRNA structure, mRNA splicing, microRNA target sites, translational efficiency, and cotranslational folding, all of which have been proposed to constrain codon choice, and thus protein evolution." (p.1325)
It should be noted that these research findings do not tell us what binding a transcription factor actually achieves. The field of gene regulation is in its infancy. The research team notes that TF binding "may serve multiple functional roles" but that their analysis is "agnostic" to this functionality. Weatheritt and Babu conclude:
"The investigation of overlapping codes opens new vistas on the functional interpretation of variation in coding regions and makes it clear that the story of the genetic code has not yet run its course." (p.1326)
This discussion of genetic codes is only meaningful if it is recognised that the genome is a carrier of complex specified information. The essence of life is not to be found in chemistry, but in the information carried within the cell. Chemicals are used to carry biological information, but the chemicals are not themselves information. The research team recognises this when they say:
"Our results indicate that simultaneous encoding of amino acid and regulatory information within exons is a major functional feature of complex genomes. The information architecture of the received genetic code is optimized for superimposition of additional information and this intrinsic flexibility has been extensively exploited by natural selection." (p.1371-2)
There is a problem with the last few words of the above quotation. The flexible information architecture is said to be exploited "by natural selection", yet this claim has not emerged from a study of evidences. Rather, the theoretical framework of neo-Darwinism provides the context for interpreting the evidences, so that all signs of complexity and functionality are automatically associated with the operation of natural selection. Yet, we have no evidence to show that natural selection can either produce or refine complex specified biological information.
There is a perfectly viable alternative hypothesis to consider: that biological information is evidence for intelligent agency. The evidence we have already about the genetic code is sufficient to make the point, but new evidences of overlapping codes add weight to the hypothesis. The genetic code with redundancy overlaps with other regulatory codes in ways that test the ability of molecular biologists (intelligent agents) to understand what's happening, let alone write overlapping codes of their own as a biomimetic exercise. From time to time, leading biologists get the message, but seem at a loss to drive it forward.
"Any living being possesses an enormous amount of "intelligence", very much more than is necessary to build the most magnificent of cathedrals. Today, this "intelligence" is called "information", but it is still the same thing. It is not programmed as in a computer, but rather it is condensed on a molecular scale in the chromosomal DNA or in that of any other organelle in each cell. This "intelligence" is the sine qua non of life. If absent, no living being is imaginable. Where does it come from? This is a problem which concerns both biologists and philosophers and, at present, science seems incapable of solving it." Pierre Grasse, Evolution of Living Organisms: Evidence for a New Theory of Transformation, (New York: Academic Press, 1977, 2).
The decision to endorse a naturalistic explanation rather than advance agnosticism about the origins of hidden overlapping codes is a pointer to hidden ideologies in origins-science. It seems that as long as materialism/naturalism is presumed, then a great number of unwarranted assertions (usually linked to Darwinism or abiogenesis) go unchallenged in academic papers. As soon as it is pointed out that only intelligent agents write codes, there is an outcry that science is being subverted by religious fundamentalists. However, the converse is true: intelligent design theory is based on the evidence of complex specified information. The evidences for naturalistic alternatives all evaporate under close scrutiny.
Exonic Transcription Factor Binding Directs Codon Choice and Affects Protein Evolution
Andrew B. Stergachis, Eric Haugen, Anthony Shafer, Wenqing Fu, Benjamin Vernot, Alex Reynolds, Anthony Raubitschek, Steven Ziegler, Emily M. LeProust, Joshua M. Akey and John A. Stamatoyannopoulos.
Science, 13 December 2013, 342, 1367-1372 | DOI:10.1126/science.1243490 [pdf here]
Abstract: Genomes contain both a genetic code specifying amino acids and a regulatory code specifying transcription factor (TF) recognition sequences. We used genomic deoxyribonuclease I footprinting to map nucleotide resolution TF occupancy across the human exome in 81 diverse cell types. We found that ~15% of human codons are dual-use codons ("duons") that simultaneously specify both amino acids and TF recognition sites. Duons are highly conserved and have shaped protein evolution, and TF-imposed constraint appears to be a major driver of codon usage bias. Conversely, the regulatory code has been selectively depleted of TFs that recognize stop codons. More than 17% of single-nucleotide variants within duons directly alter TF binding. Pervasive dual encoding of amino acid and regulatory information appears to be a fundamental feature of genome evolution.
Weatheritt, R.J. and Babu, M, M. The Hidden Codes That Shape Protein Evolution,
Science, 13 December 2013, 342, 1325-1326 | DOI: 10.1126/science.1248425
Klinghoffer, D. Genome Uses Two Languages Simultaneously; Try That Yourself Sometime, Why Don't You, Evolution News & Views (December 13, 2013)
Luskin, C. Codes Within Codes: How Dual-Use Codons Challenge Statistical Methods for Inferring Natural Selection, Evolution News & Views (December 20, 2013)
This Discovery Institute seminar will prepare students to make research contributions advancing the growing science of intelligent design (ID). The seminar will explore cutting-edge ID work in fields such as molecular biology, biochemistry, embryology, developmental biology, paleontology, computational biology, ID-theoretic mathematics, cosmology, physics, and the history and philosophy of science. This seminar is open to students who intend to pursue graduate studies in the natural sciences or the philosophy of science. Applicants must be college juniors or seniors or already in graduate school.
Quantum phenomena in biology are receiving the attention of more and more researchers, with photosynthesis being the process getting the most attention. Back in 2007, it was apparent that quantum effects were effective for "explaining the extreme efficiency of photosynthesis". Then, in 2010, the photosynthetic apparatus of cryptophyte algae was the focus of research, because its pigments are farther apart than was expected for efficient functioning. In a News & Views article in Nature, van Grondelle & Novoderezhkin discussed evidence suggesting that a process known as quantum coherence is part of the explanation. They added: "This is the first time that this phenomenon has been observed in photosynthetic proteins at room temperature, rather than at much lower temperatures, bolstering the idea that quantum coherence influences light harvesting in vivo." The most recent study has provided a theoretical argument that quantum effects must be present and that classical physics does not provide an explanation. It is claimed to be "the first unambiguous theoretical evidence of quantum effects in photosynthesis". The Press Release describes the work in this way:
"Often, to observe or exploit quantum mechanical phenomena, systems need to be cooled to very low temperatures. This however does not seem to be the case in some biological systems, which display quantum properties even at ambient temperatures. Now, a team at UCL have attempted to identify features in these biological systems which can only be predicted by quantum physics, and for which no classical analogues exist. "Energy transfer in light-harvesting macromolecules is assisted by specific vibrational motions of the chromophores," said Alexandra Olaya-Castro (UCL Physics & Astronomy), supervisor and co-author of the research. "We found that the properties of some of the chromophore vibrations that assist energy transfer during photosynthesis can never be described with classical laws, and moreover, this non-classical behaviour enhances the efficiency of the energy transfer."" (Source here)
New frontiers for understanding the natural world (image source here)
Most light-gathering macromolecules are composed of chromophores (the light-absorbing pigments) attached to proteins. These are responsible for the first step of photosynthesis, which is to capture light and transfer its energy to another system that can store it. Earlier work showed that energy is transferred in a wave-like manner (the quantum coherence model). However, theoreticians were of the opinion that classical physics could still find a way of explaining the observations.
"Molecular vibrations are periodic motions of the atoms in a molecule, like the motion of a mass attached to a spring. When the energy of a collective vibration of two chromophores matches the energy difference between the electronic transitions of these chromophores a resonance occurs and efficient energy exchange between electronic and vibrational degrees of freedom takes place. Providing that the energy associated to the vibration is higher than the temperature scale, only a discrete unit or quantum of energy is exchanged. Consequently, as energy is transferred from one chromophore to the other, the collective vibration displays properties that have no classical counterpart. The UCL team found the unambiguous signature of non-classicality is given by a negative joint probability of finding the chromophores with certain relative positions and momenta. In classical physics, probability distributions are always positive." (Source here)
Bear in mind that considerable resources have already been spent on trying to develop a biomimetic system that captures solar energy like plants - only to find that photosynthesis is extraordinarily complex and the research has not yet delivered any commercial outputs. It is a reminder that the Darwinian vision of ultimate simplicity has been repeatedly falsified. Photosynthesising microorganisms are among the earliest to appear in the Precambrian fossil record - and yet these organisms have chemical and physical pathways that are only beginning to be understood within the research community. What is emerging are processes and structures that carry the hallmarks of design, with complex specified information at every level of analysis. We are at the beginning of a journey into quantum effects in biology. It is the design paradigm that is best equipped to guide our thoughts and keep us on the right path.
"Other biomolecular processes such as the transfer of electrons within macromolecules (like in reaction centres in photosynthetic systems), the structural change of a chromophore upon absorption of photons (like in vision processes) or the recognition of a molecule by another (as in olfaction processes), are influenced by specific vibrational motions. The results of this research therefore suggest that a closer examination of the vibrational dynamics involved in these processes could provide other biological prototypes exploiting truly non-classical phenomena." (Source here)
Non-classicality of the molecular vibrations assisting exciton energy transfer at room temperature
Edward J. O'Reilly & Alexandra Olaya-Castro
Nature Communications, 9 January 2014, 5, Article number:3012 | doi:10.1038/ncomms4012
Abstract: Advancing the debate on quantum effects in light-initiated reactions in biology requires clear identification of non-classical features that these processes can exhibit and utilize. Here we show that in prototype dimers present in a variety of photosynthetic antennae, efficient vibration-assisted energy transfer in the sub-picosecond timescale and at room temperature can manifest and benefit from non-classical fluctuations of collective pigment motions. Non-classicality of initially thermalized vibrations is induced via coherent exciton-vibration interactions and is unambiguously indicated by negativities in the phase-space quasi-probability distribution of the effective collective mode coupled to the electronic dynamics. These quantum effects can be prompted upon incoherent input of excitation. Our results therefore suggest that investigation of the non-classical properties of vibrational motions assisting excitation and charge transport, photoreception and chemical sensing processes could be a touchstone for revealing a role for non-trivial quantum phenomena in biology.
Cartwright, J. Quantized vibrations are essential to photosynthesis, say physicists, physicsworld.com (22 January 2014)
Tyler, D. Explaining the extreme efficiency of photosynthesis. ARN Literature Blog (16 April 2007)
Tyler, D. The latest thinking on how photosynthesis evolved. ARN Literature Blog (11 February 2007)
All ten right HERE.
A great article by Tom Bethell in ENV...
From Nature Magazine...If our planet were just a little closer to the Sun, a runaway greenhouse effect would render it unliveable, a climate model suggests. The simulation, which helps to define the inner edge of a star system?s 'habitable zone', drastically reduces the fraction of Sun-like stars that might harbour a rocky planet suitable for life, according to some scientists. But others note that the model, although detailed, might be too restrictive because it applies only to Earth-like planets on which water is abundant.
Of course we are also asked to believe that the right planet, just at the right distance from its star, will naturally generate life from non-living chemicals...
What happened here is that a group of adults can?t have a class taught by a qualified person on a topic that interests them in a suitable public venue because an individual is allowed to shut it down?just by scaring people by making a scene.
In the 19th century, Christians responded to the challenges of Darwinian evolution in many and diverse ways?from hostility to reconciliation. Read about the reactions of theologians, scientists, pastors, authors, bishops, and politicians?and learn how Darwinism eventually became a symbol of warfare between science and Christianity in this issue of Christian History magazine.
Click HERE to read...