Antoine Boutros

Behind all the advancements achieved by man, information has played a very important role. Before every step taken in the life of a human being and his evolution, information again plays a very important role as the main carrier of instructions. All this happens in the cell and in particular in the DNA and the process by which information is relayed is very complicated.

The DNA molecule has a double helix shape and when measured it is 4.3 nanometers long, has a radius of 2 nanometers and a density of  0.0 000 000 000 000 000 000 1068 cubic meters (10.68x10^-21). Since each part of the DNA’s partition (located between the two helical chains) contains ten chemical symbols (called Nucleotides), this means that we encounter an information density with a capacity of 0.94x10²¹ (the number 94 plus 19 zeros) for every cubic centimeter.

During the process of conception, these symbols act as a genetic code that transfers instructions to the fetus, which not only defines the character of the newborn but also all its characteristics. Its basis is four symbols that are repeated in a certain pattern and differ from one person to the other. This code controls a living organism’s path of life in its entirety. Every development or biological event that takes place in the life of a living organism is dictated by information present in the DNA molecule. When a certain error occurs in copying information, a mutation occurs. Mutations can sometimes be beneficial in the process of evolution, such as opening new outlets in precarious abrupt environmental cases. In other words, it leads to adaptation. But mutation is also a great source of danger, from a medical point of view. 

According to the theory of information formulated by Claude Shannon, each symbol of this code is equal to a square bit. Accordingly, the density of information for the DNA molecule is estimated at 1.88x10²¹ bit/cubic centimeter.

Every living organism contains proteins that form the main substance from which all organisms are composed. These proteins contain the necessary components to operate life, most significantly enzymes, anti-bodies and hormones. But these components are specific, both in part and kind, meaning that they are particular to each body part and the same goes for every form of life. In human beings, who represent an independent form of beings, there are no less than 50,000 different kinds of proteins, each with a specific mission. The formation of these proteins is defined by an information code that enables them to perform precise chemical operations in the cell. All the proteins go back to only 20 kinds of amino acids that are described as the cornerstones of life. Their structure also follows a specific code and the sequence of this structure is itself very important due to the dangerous results that might ensue if it is altered.

Living organisms cannot survive without information. For example, the whale needs to perform a high number of operations to ensure its survival. It needs to know how to transform plankton – microscopic animal and plant organisms that float on the water’s surface – into fat. It also needs to know how to dive into the depths of the ocean (one kilometer below water surface). All of this is inscribed as information in the whale’s genetic genes. The whale is like the human being, it has a specific enzyme – hexokinase – in charge of turning the sugar molecule, which is extracted from the plankton, into energy without which it cannot survive. 

Other living organisms also cannot survive without information. For example, a virus has no less than 10,000 bits of information – equal to one book page – in the form of a code. Bacteria, which is more complex, needs no less than one million bits of information – equal to 100 pages – because they are not parasites like viruses, rather they feed from themselves in order to survive. Amoeba, which is a single-cell bacterium, continuously changes form and contains 400 million bits of information enabling it to regulate all aspects of its life, meaning if we want to make a copy of it we need a 500-page guide.

Shannon’s theory on information allows us to specify the smallest number of codes or “coded letters”. Scientists estimate that the 20 kinds of amino acids contain an average of 4.32 bit of information for each amino acid. If we assume that codes or chemical “instructions” consist of two letters, and every word consists of four bits, then the amount of information it carries is low. In comparison, if we adopt a four-way system, then four-code words will consist of eight bits per word and then it becomes very complex. However, based on Shannon’s theory, a three-word code, made up of three codes or “letters”, forms a group of six bits per word and is therefore a sufficient, economical and effective language to be used in coding. Scientists believe that this is what nature sought at the level of information coding.