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NITAAI-Veda.nyf > Soul Science God Philosophy > Science and Spiritual Quest > Section 4 Towards a New Biology > MOLECULAR EVOLUTION: QUANTUM MECHANICS > 3. Approach > 3.3 Implications & Discussion

3.3 Implications & Discussion


The heuristic exercise above leads to a few intriguing implications.


1.The first Wigner inequality sets fundamental constraints on the motor's accuracy for reading DNA. Our numerical estimates are comparable to known error rates of the polymerase motor.

2.The second Wigner inequality sets fundamental constraints on the motor's precision and information processing power. This exercise suggests that the information content or the number of bits stored in a DNA-motor system is much larger than that typically assumed (1 bit perbase). This increase in information storage density results from the motor itself having several internal microscopic states. Conventionally, information in DNA is seen as being stored in the DNA bases itself. This work, in contrast, suggests that DNA, the replicating motors, and their environment comprise a dynamic and complex information-processing network with dramatically higher information storage and processing capabilities.


3.The power of information processing was compared to the actual power generated by the motor as it consumes energy to mechanically move along a DNA track. Molecular motors provide an excellent laboratory for probing the interplay of matter, energy, and information. These molecules (matter) transduce chemical free energy into mechanical work with remarkably high efficiency; and in ways (as of yet unknown to us) information from their environment plays a critical role in controlling or modulating their dynamics. What is needed is a more rigorous conceptual framework, where the molecular motor's dynamics can be intrinsically and strongly coupled to its exchange of information and energy with its environment.


4.The decoherence times for the motor-DNA system was found to be on the order of minutes to hours, paving the way for quantum mechanics to play a non-trivial role. In order for quantum effects on the motor dynamics along DNA to enter the realm of experimental detection, a few prerequisites must be met: i) the decoherence times must indeed be sufficiently long; ii) single molecule experiments must be carefully designed so that they do not destroy coherences; and iii) we should look more seriously for emergent macroscopic quantum effects, including for instance evidence for quantum information processing occurring within these molecular systems.


There is fervent interest in developing technologies that can store, retrieve, and process information at the nanoscale. Biological systems have already evolved the ability to efficiently process remarkable amounts of information at the nanoscale. Perhaps futuristic quantum information technologies could find their best realization yet in the context of biomolecular motors. In his classic book, What is Life, Schrodinger [1] first speculated that quantum mechanical fluctuations could give rise to mutations. In more recent times, McFadden [13] describes how quantum mechanics may provide a mechanism for understanding "adaptive mutations"-i.e.mutations that are not purely random but are driven by environmental pressures. We have discussed how Wigner relations limit the accuracy with which polymerase motors can copy DNA. This suggests that mutations are fundamentally built into the replication machinery. We have also argued that these complex macromolecular systems can have decoherence times that are long compared to the timescale associated with the motor reading a DNA base, suggesting that quantum features are not really destroyed in these systems. We can dare to speculate and ask some provocative questions: Could quantum noise or fluctuations perhaps give rise to mistakes made during the motor's copying of the DNA. Since these motors propagate genetic information, such molecular mistakes made during DNA replication lead to mutations in the organism. Could the environment be somehow deeply entangled with the dynamics of these molecular motors as they move along DNA? Could information embedded in the motor's environment somehow modulate or influence its information processing, and hence how it reads the DNA bases? Could the environment somehow be selectively driving evolution and if so could it be that evolution, at least at the molecular level, is more Lamarckian than it is Darwinian?As fields like nanotech, biotech, and quantum information processing come together and new fields like quantum biology are born, it will become more fashionable to ask such questions and increasingly possible to experimentally address them.


Could the environment somehow be selectively driving evolution and if so could it be that evolution, at least at the molecular level, is more Lamarckian than it is Darwinian?