Jaw Drop #7 – How much can we know about something? The C. elegans story.

Scientific research is pushing every single day towards a better and deeper knowledge. Either for curiosity, advancing the foreground of what humans know, or for finding a cure for cancer, every day many scientific publications appear on the most exotic journals around the world.

But how much can we know? Is there a limit to what can be achieved in our minds or in our labs? I want to give you a clean example of how much our knowledge can be expanded and have been expanding.

In biological research, the use of model organisms is very common. Who is using primates, who is using mice and who is using yeast cells, everybody hopes to find something about our world extrapolating findings from these organisms to us or to the natural world.

What you might not know is a pretty popular model organism called Caenorhabditis elegans. This little guy is a very simple almost transparent nematode. Yes, it is a worm; and in years of study, it allowed us to get countless insights on developmental biology, genetics, cell biology and much more, including between others, the most notable RNA interference, and Apoptosis discoveries.

Why do I want to talk about a worm that you can find in your back garden that is used in the labs all over the world? Well because of this guy we know a lot. And I mean it, a lot.

For example, when you think you know yourself, what do you actually think you know? You know your personality? You know your defects? You even know every single mole on your skin! Well, let me tell you: as much as we have more to discover in C. elegans we know every single cell of it!! Exactly! Everysinglecell!

Ok, but what does it mean? Well, you know that we all origin from a single cell that in our case gets originated from an act of fecundation right? For this worm, everything is the same with the difference that it can reproduce asexually as well. So to get all of our cells from that single original cell, you might imagine there is a lot of work to be done.

It turns out that C. elegans has up to 1031 cells in adult males (but is normally 959 in adult hermaphrodites). I am not saying random numbers, we mean that adults have ALWAYS that number of cells in their body if they are not affected by some genetic condition or illness. We don’t only know how many cells they have but what exactly every single one of those cells does and is in the body. If that doesn’t sound amazing and utterly outstanding at first there you go:

lineage
The fate of every single cell in our worm. (http://wormatlas.org/celllineages.html) if you want to check more.

What you see in this graph is every cell division that occurs from a single cell, the embryo, and the adult organism. From top to bottom you can see how every branching in the flowchart doubles the quantities of cells. Every cluster of cells represents different functional department of the tissues formed by these cells.

This is crazy impressive. From the starting embryo, we can track down every single cell in that organism!! Okay, it doesn’t have that many cells but still, this is mindblowing!

You haven’t got enough? In this website, you can find the whole connectome mapped in this organism. What does that mean? In simple words, that we know every single neuronal connection in the whole nervous systems in this worm! In practice, we know which cell (neuron) connects to every other cells in the whole body!!

This is really impressive, and if you thought your knew something about an organism, well think twice, because you will never know as much as I just told you. While you think about this immensity, let me tell you another story…

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