From editing towards engineering genes (An introduction to Synthetic Biology – Part I)

Modern technology avails countless possibilities. Yet, the thought of similar innovation in human biology seems distant and confined to fiction books. But, there is light at the end of the tunnel, a day is not far off when diabetics don’t need to inject insulin and cancer treatment can be a lot less painful. Synthetic Biology is all set to revolutionize medical treatment, as we know it.


Engineering has been a significant driver of the present-day society. And all this development over the past couple of centuries has been accelerated with the generation and use of electricity. Starting with lighting a bulb we have come a long way. If you have ever worked with a device that uses electricity or a circuit these days, you must have dealt with logic gates. AND, NOT, OR and the rest of them from the building blocks of any modern day electrical circuit, like the one behind lighting up your mobile screen. Of course, a critical component used in hordes is the transistor.


While a bulb lights up once a circuit is complete i.e. when the switch is turned ON, modern devices are complex by many magnitudes. A microwave oven provides a simple example of AND gate for only when the door is closed and the start button is pressed, will the oven cook. [AND gate outputs ON only when both inputs are ON, otherwise, it’ll turn OFF]. Electrical engineering deals with all that is discussed above and much more, including signals sent from a spacecraft flying by Pluto. These are where microchips are used (that employ billions of transistors). “OK! I already knew or had a good idea of what electrical engineering is.” That’s what you are thinking right? Then, how about this? Electrical engineering, starting from the basics, is being integrated into life sciences. There’s a whole discipline dedicated to this and is called ‘Synthetic Biology’. But how is anything relatable between OR gates and organs? Read on.


First up, logic is defined as “a particular system or codification of the principles of proof and inference”. In engineering terms, logic is “a system or set of principles underlying the arrangements of elements in a computer or electronic device so as to perform a specified task”. So, how is computer logic related to humans? It’s not about building bionic arms or even humanoid robots. Like transistors and related logic gates, there are certain entities that form the building blocks of life forms, genes. At its most basic form, when a gene is activated, the encoded protein will get activated and a function is performed.


Engineering the biology of Life


The UK Royal Society defines Synthetic Biology as “Synthetic biology is an emerging area of research that is described as the design and construction of novel artificial biological pathways, organisms or devices, or the redesign of existing natural biological systems.” Although it does state this as an “emerging area”, humans have been dabbling with genes for millennia. We have been altering the genetic code of plants and animals through selective breeding for desirable features. Once the basics were well understood, bio technologists worked on tweaking the genetic code itself. One might remember how they are able to transfer the genetic data from one organism to another. Golden rice is a good example that was developed to help balance vitamin deficiency in people.


Although we consider ourselves as complex organisms, at a cellular level, it does seem that principles of logic gates do govern. Dionaea muscipula, more commonly known as Venus flytrap, provides an elementary yet effective logic circuit style functioning. The leafy jaw that the plant opens and closes to devour its prey functions based on the following logic. Once the hair on the inside of the jaw detects a fly or any potential food, a timer is set off. If and when a second hair is triggered, then the jaws shut within one-tenth of a second, which is proof of the size of energy that drives this mechanism. This mechanism allows for conservation of energy and avoids wasteful expenditure during those times when a hair is disturbed by a passing object. This can be broken down into a logic-based operation. The AND gate is set as ON only when both the inputs are ON. Only when both the hairs are triggered within a time span of twenty seconds, the jaw will draw shut. A similar pathway might read “IF TRIGGER 1 + TRIGGER 2 < 20”, THEN CLOSE JAWS.” The mechanics are initiated and controlled by proteins. Unlike some actions involving a cognitive push, this is an example of a simple and straightforward functioning of pre-determined logic.


Notes:


  • This series is inspired by Chapter 9 – “Logic in Life” of the book “Creation: How Science is Reinventing Life Itself” by Adam Rutherford. [Rutherford, A. (2013).Creation. New York: Current.]

  • Synbio Project org. (2018).What is Synthetic Biology? – Synthetic Biology Project. [online] Available at: http://www.synbioproject.org/topics/synbio101/definition/

  • co.uk. (2018).BBC – GCSE Bitesize: Genetic engineering. [online] Available at: http://www.bbc.co.uk/schools/gcsebitesize/science/add_gateway_pre_2011/living/genesrev3.shtml

  • National Human Genome Research Institute (NHGRI). (2018).Human Genome Project Completion: Frequently Asked Questions. [online] Available at: https://www.genome.gov/11006943/human-genome-project-completion-frequently-asked-questions/

  • Randerson, J. (2018). How many neurons make a human brain? Billions fewer than we thought | James Randerson. [online] the Guardian. Available at: https://www.theguardian.com/science/blog/2012/feb/28/how-many-neurons-human-brain

 

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