Networks of genes, nerve cells in the brain, food chains, as well as the Internet are organized according to building principles, some of which are shared
Bischem Azgad
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A research group headed by Dr. Uri Alon from the Department of Molecular Biology of the Cell at the Weizmann Institute of Science, revealed several recipes (motifs) according to which networks of different types are organized. , or nerve cells in the brain, or food chains in nature, and even the Internet. This discovery is a pioneering step And important on the way to the development of future medicine, which will allow "repair" and return to operation of biological systems that have "broken down".
The mathematical method by which the discovery was made was proposed by Dr. Alon in an article published a few months ago in the journal "Nature Genetics". In the current study, Dr. Alon was able to prove that the principles of the method are indeed held in practice in a large number of systems and networks in various fields.
The method was born as a result of Dr. Alon's assessment that construction recipes that play an important role in nature will appear with a much higher frequency than expected randomly. This guideline, Dr. Alon believed, may lead To find the principles of building different networks in biological systems. Using an algorithm he developed, Dr. Alon examined many scientific findings that exist in the systems of several microorganisms and animals that have been extensively studied and that the accumulated information about them is broad and comprehensive. In this study he distinguished In the fact that a number of patterns in these systems appeared with a much higher frequency compared to the rate at which they appeared in random networks that he built for the purpose of comparison, Dr. Alon hypothesized that these repeating patterns, represent deep principles according to which biological systems and networks are organized.
"Surprisingly," says Dr. Alon, "we found two common motifs in genetic and nervous systems. Apparently these two systems, which both deal with information processing, chose to organize themselves in a similar way. It is possible that the shared motifs were chosen in order to reduce the intensity of the 'biological noise' and thereby enable a more complex and precise activation and deactivation of the genes or nerve cells. We believe that the shared patterns form particularly important communication circuits, which play key roles in the control processes of the cell. This 'architectural' or 'engineering' concept is reminiscent of the way electronic engineers work, who repeatedly integrate the same well-known electronic circuits at the center of various technological systems."
Revealing the nature of the building principles of biological systems and networks, as well as the fact that some of them are shared by different systems, may help scientists to categorize the systems (just as camels and mice both belong to the same family, the mammalian family, genetic and nervous systems could also be associated with the same family). The meaning of family association may be quite broad. Dr. Alon says that it is possible that in this way it will be possible, for example, to learn about the nervous system of animals, through the investigation of the genetic system in bacteria, which is more accessible.
"The dream," says Dr. Alon, is to find and understand all the laws that govern our body, thus fully revealing the way the living cell works, and the ways to repair it, if and when it breaks down. One day, in the distant future, we hope That a doctor's work would be similar to that of electrical engineers today: they examine the building plan of the 'broken' animal or person, and then, simply fix it and return it to normal operation."
Dr. Alon's research team included research students Ron Milo, Shalu Itzkovitz, Nadav Kashtan, and Shai Shen-Or.
Construction principles common to different networks:
1. Front feeding
This pattern called "front feeding" is found in gene control networks and neural networks, and it is used, apparently, to neutralize "biological noise" and to perform fast measurements.
For gene Z to be expressed, or for nerve cell Z to send an electrical signal, both cells X and Y must send it a signal at the same time (a communication molecule in the case of genes, or an electrical signal in the case of nerve cells).
2. Combinatorial switch
This pattern, known as a "combinatorial switch", is applied in gene control and neural networks. Different combinations of X and Y give different results of a and b.
3. Production line
This pattern, known as an "assembly line", is implemented in networks of gene control.
When X is activated, even at a relatively low intensity, this will be expressed in the product a. As the intensity of the activity increases, b, c, and d will also begin to form, in order. "Shutting down" the system will be manifested in the reduction of the production of the various products, in reverse order.
4. Food chain
This pattern - which is different from the operational features that exist in networks of genes and nerve cells - describes a structural principle of food chains in nature. Carnivores generally do not eat the food of the animals they prey on. For example, a lion preys on the deer that eats grass, but the lion does not eat grass.
Omnivores, such as humans, are rare in nature, and the pattern that describes their food chain is the one known as "front feeding".
5. Parallel tracks
This pattern is applied, for example, in food chains in nature and in neural networks. Animals that are preyed upon by the same predator (for example, a deer and a zebra, both preyed upon by a lion), usually feed on the same types of food (in this example - grass). This pattern was not found to a significant degree in networks of genes, but it appears in networks of nerve cells: if two neurons are activated by one neuron, the signal they send will activate the same neuron many times.
Home page of Dr. Uri Alon at the Weizmann Institute
https://www.hayadan.org.il/BuildaGate4/general2/data_card.php?Cat=~~~368661737~~~65&SiteName=hayadan
