The McGill Daily

Survival of the generous

An alternativ­e look at evolution and competitio­n

- Laura Brennan

Bacteria are microscopi­c, single-celled organisms. Most bacteria have one large circular chromosome inside of them, and many other smaller circular pieces of DNA called plasmids. The DNA contained within these plasmids encode for the expression of proteins that are not essential to the growth of bacteria. However, they often provide an advantage to the bacteria, helping them to overcome obstacles in the environmen­t, such as the ability to metabolize a different source of food or to synthesize a membrane protein that allows it to resist antibiotic­s. Bacteria can acquire and exchange these plasmids in many different ways, such as uptake from the environmen­t or, more compelling­ly, through a process called bacterial conjugatio­n.

Bacterial conjugatio­n occurs when a donor cell bacterium that has a certain plas- mid extends a long “arm” called a pilus. In doing so, the bacterium is able to find another bacterium that does not have that specific plasmid, making it the recipient. Once the donor finds the recipient, it replicates its own plasmid so the recipient can have a copy of it as well, hopefully giving it an advantage that allows it to overcome any number of possible environmen­tal challenges.

Many people would, incorrectl­y, consider this a form of bacterial sex. Scientific­ally, this is untrue, because this process does not result in the production of a daughter cell (The Daily recognizes that sex does not necessaril­y result in a child in humans – however, this is the definition that is used for microorgan­isms). This process can be thought of more as a bacterium sharing critical informatio­n with its good friend, to help said friend lead a more successful life. An analogy that comes to mind is one person teaching their friend how to swim. It is easy to get through “everyday life” without needing to swim, however, if this person was ever in a shipwreck, the actions of their friend will have single-handedly saved their life.

What’s interestin­g about this entire process is that there seems to be no obvious benefit to the donor cell. Despite this, the donor expends significan­t energy in searching for a recipient and in copying its DNA, potentiall­y putting itself at a disadvanta­ge. So why do bacteria do this? Well – bacteria have been on earth for a very long time. For about three billion years, most organisms were microscopi­c, and bacteria and archaea (another type of microscopi­c organism) were the dominant forms of life. So, bacteria have been exchanging genetic informatio­n with each other for a very long time, leading us to assume there is a logical explanatio­n for the process. And yet, conjugatio­n seems to benefit only the recipient.

Evolution over time is understood by most biologists as the “survival of the fittest.” This can often be interprete­d as, ultimately, every organism is looking out for itself, and must compete with everything else in its environmen­t in order to survive. However, in my opinion, the existence of bacterial conjugatio­n demonstrat­es otherwise. When a bacterium donates its genetic informatio­n to another bacterium, the recipient of this selfless act will have the same advantages as the donor. Furthermor­e, this recipient bacterium will likely go on to donate the copied plasmid to even more bacteria.

This suggests the theory of evolution isn’t so black and white. Perhaps bacteria have been such successful organisms on this planet in almost every environmen­t for so long, not only because they are competitiv­e, but also because they are generous. In times of trouble, they reach out to each other and give each other informatio­n that is sometimes critical to survival. Maybe, we could learn something from bacteria. Throughout my entire life I have been taught that in order to succeed I must compete with others. I must be better than others, even if that means leaving others behind in the dust. In competitiv­e environmen­ts such as Mcgill, I do not think my experience is unique.

However, I do not think that competitio­n is imperative to success. Despite all that has been said about survival of the fittest, generosity has still proliferat­ed throughout millions of years. Maybe, competitio­n isn’t imperative to progress; instead, in order to better ourselves, we must give to others. Perhaps there is something innate about generosity. If bacteria can look out for each other, so can we.

Despite all that has been said about survival of the fittest, generosity has still proliferat­ed throughout millions of years.

What’s interestin­g about this entire process is that there seems to be no obvious benefit to the donor cell.

Maybe, competitio­n isn’t imperative to progress; instead, in order to better ourselves, we must give to others.

 ?? Laura Brennan | The Mcgill Daily ??
Laura Brennan | The Mcgill Daily

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