Once again, I was looking through RadioLab and I found a very interesting show about giant viruses. The average size of a bacteriophage is about 6.5 nm long. Spherical viruses average around 100 nm. The average for these newly discovered giant viruses called are about 400 nm in diameter. These huge viruses enter a bacteria and float inside the cell. Instead of just injecting its DNA and going through that normal viral lytic cycle, it lives there in a commensalistic relationship. Inside the cell, the virus is called a virus factory. The virus takes in materials floating around the cell and reassembles them into components to build more giant viruses. Get this-the holes where the materials go in and out are called stargates. Awesome right? And turns out there are even bigger viruses other than the 400 nm mimivirus. In order from smallest to biggest: mimi, mama, mega, and then pandora, measuring over 1000nm.
The theory of the origin of these huge viruses are that they might have been living cells and switched sides for some reason. At some point a microbe finds itself inside another cell and is able to thrive there. It basically had protection from the environment, and food delivered to it. From there evolution got rid of there energy forming processes, for they are no longer necessary.
This discovery is very eye-opening because it shows how not only can life on Earth evolve to become more complex, but can also evolve to become more simple. In the case of the giant viruses, they started out as full sized microbes and over time shrunk due to evolutionary pressures. In human evolutionary history we were once able to produce our own vitamin C but lost that ability some point in history. This was allowed to happen without hurting the human population because vitamin C has always been plentiful in our diets. Like I said in my last blog post, cell division is not always perfect. There had to have been a mutation in a cell where their vitamin C producing mechanism was damaged. However, since humans were still able to receive vitamin C from fruits, this mutation was able to remain in the gene pool and passed on to future generations. This sparked an interesting question. If humans have lost functions before, couldn’t we lose more in the future? What if a mutation arises where we are born without a toe. Prosthetic and custom shoes and whatever else can make life with one less toe normal. Therefore, this gene for 9 toes will remain in the gene pool and spread and eventually humans as a species could have only 9 toes instead of 10.
In the brilliant shoe, West World, Dr. Ford, when referring to the human race in the distant future says, “this is as good as we get.” With every disease cured, every disability fixed, there is no evolutionary pressure being put or our species. No genes leave the gene pool and that’s including the bad genes. I guess this is a problem we’ll confront later when we are washing our hands with bleach because that .001% of bacteria that your favorite antibacterial soap didn’t kill have grown in numbers.