Divide and Conquer

I have a post rattling around in my mind, about the joys and frustrations of studying a complex science over a tenuous internet connection. This is not that post.

Sometimes I lay awake at night, staring at the ceiling and marveling at the complexity of life. It’s a big, crazy world out there, how can a person sleep in that sort of cacophony?

One thing that constantly amazes me is that every cell in your body has the same genetic code. Each cell in your liver, in your bone marrow, in your eye, in your skin is all spun from the same cloth. Vastly different functions, same “programming”, if you will.
So how do you take one genome and get literally thousands of different kinds of cells? This is the cool part- we don’t exactly know. Savor those words- we don’t know. Of course, we have some idea- it all comes down to so-called stem cells, generic undecided cells that can go on to become many different sorts of cells depending on which cytokines they are marinated in. Scientists are still untangling the specifics but stem cells are ever-present in the public conscience due to manufactured political squabbles over research on embryonic tissues, despite the fact that adult stem cells are showing far more promise.

When I was growing up, “stem cells” were the new miracle drug; with the promise to cure all diseases, heal all disabilities, and royally tick off the religious right all at the same time. As you might imagine, that never quite materialized but new advances are still being made and it’s a very interesting field.

The production of blood cells (red blood cells, white blood cells, and platelets) is through a process of proliferation and differentiation called hematopoiesis. All blood cells are descended from a pluripotent stem cell in the bone marrow, which goes through a series of cell divisions, maturing and changing along the way to become the mature circulating cells we recognize.

This is a chart I made for my hematology class which shows the maturation of blood cells. I found that different sources organized their hematopoiesis charts a little different, I chose the method that made the most sense to me. However, not until I scanned it did I notice I missed a cell- can you spot which one?