On this website we like to argue that networks are all around us: be they transportation networks, the internet, financial networks, or the electricity grid. But we also argue that networks are inside of us. Some of these examples are fairly obvious: we all know, for instance, that the brain is basically a huge and complex network of nerve cells. But there are some networks inside of us that are not nearly as obvious.
One beautiful, extremely important hidden network is the network of gene interactions: our DNA contains tens of thousands of genes. Some of these are really important. If you don’t have even one of them, you can’t live. But most genes can easily be done without, because there is another gene that does basically the same thing somewhere else on the DNA. Only if both genes are disabled does the trouble start. This makes our genetic code especially robust.
A small gene-interaction network [1]
Last week a publication appeared in the journal Science, where scientists present a comprehensive study of these pairs of genes in yeast cells. The result of their seventeen-year-long experiment is that if we draw the genes in the yeast’s DNA as nodes of a network, and we draw links between pairs of nodes if both genes cannot be disabled at the same time, then we get a network that is completely connected, and that has a beautiful hierarchy. Moreover, the network can be used to figure out what a gene does just from looking at what it’s neighbors in the network do. A huge advance in the way we study gene functionality! In fact, the network has already been used to figure out what one of the six important “mystery genes” of yeast does: a gene we know yeast can’t do without, but for which we also didn’t know what it does.
You can look and play with the network on the researcher’s website, or even download the whole data set, if you’re more seriously interested. There is also an excellent long feature on Quanta magazine that explains the experiment and the network with Quanta’s usual clarity, and has interviews with the researchers who did the experiment.
By Hennah, Porteous - [The DISC1 Pathway Modulates Expression of Neurodevelopmental, Synaptogenic and Sensory Perception Genes http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0004906], CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=7681986
It is quite difficult to extract information from your body. Your body is so vast that millions upon millions of messages get sent and deleted every second. It is impossible to know exactly who said something. The doctor’s main challenge is finding a way to reconstruct the network of interacting cells given the limited information she can measure.
At this very moment, the emergent science of DNA self-assembly is giving birth to a new field of mathematics that might be called DNA-mathematics. Cleverly constructed DNA molecules will self-assemble into pre-determined complex structures when placed in solution together.
After having a near-fatal accident falling off his horse, Prussian footman Hans Berger (1873—1941) was surprised to learn that his sister had—being kilometers away—him a telegram to let him know that she sensed he was in grave danger.
Between 1973 and 1986 multiple rapes and murders were committed in the state of California. Years later the idea was raised that these crimes might be connected. But traditional DNA analysis from the samples found at the crime scenes, could not identify the culprit.
The Netherlands Forensic Institute (NFI) has a great deal of in-house knowledge in the field of forensic products, research and services, and provides many organizations in the field of security and law with reliable information from traces. Mathematical models are used within the NFI to understand the evidential value of the traces found.
![By Hennah, Porteous - [The DISC1 Pathway Modulates Expression of Neurodevelopmental, Synaptogenic and Sensory Perception Genes http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0004906], CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=7681986](https://www.networkpages.nl/wp-content/uploads/2016/11/Network_of_how_100_of_the_528_genes_identified_with_significant_differential_expression_relate_to_DISC1_and_its_core_interactors.png)
![By Hennah, Porteous - [The DISC1 Pathway Modulates Expression of Neurodevelopmental, Synaptogenic and Sensory Perception Genes http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0004906], CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=7681986](https://networkpages.nl/wp-content/uploads/2016/11/Network_of_how_100_of_the_528_genes_identified_with_significant_differential_expression_relate_to_DISC1_and_its_core_interactors-300x195.png)
