Stem Cells Tutorial

Blog entry

It’s summer time so I have some time off from teaching and I’m beginning to feel the “academic itch.” So, I thought it might be a good idea to review the ideas, promises, and issues with stem cell biology. While a lot of the controversy has taken a back seat to other issues, they are still present and I will use this month to present my take on the whole thing. Now although I am far from unbiased, as a scientist I am bound by ethics and my desire to educate (not brainwash), to present a fair and balanced blogpost: So here goes nothing…

Stem cells are described as having three fundamental characteristics:
1- The are able to divide to make more of themselves
2- They are essentially un-specialized, or as I like to put it, under-specialized
3- They have the ability to differentiate (mature) into many different cell types


They were originally discovered in mouse spleen by Till and McCollough, a Canadian super-duo who, while they understood the implications of their discovery, may have not known they were about to spark a revolution. Here’s a link to the original piece of work:

It wasn’t until 20 years later that Gail Martin, a promising young postdoc from Martin Evans’ lab who scored a tenure track post at UCSF, and Martin Evans himself in Britain at the time, simultaneously developed the first mouse embryonic stem cell cultures. Sir Evans gets the lion’s share of the credit, but one should never make the mistake of underestimating Dr. Martin’s importance to the stem cell world.  One example: She coined the term “embryonic stem cell” which should tell us that she was right there, in the thick of it, making science happen. The revolution had begun. Two separate labs figured out how to harness the technology of the day to isolate, expand, and maintain a self-replenishing pool of cells capable of making every single cell in the body. Totally rad. Here are some links:

So to recap, Till and McCollough discover a population of cells that can regenerate spleen tissue, effectively discovering the first adult stem cell population. Then, Gail Martin and Martin Evans discover and identify the embryonic stem cell and describe how to grow them in culture. Dr. Martin begins her stellar career in style, and Dr. Evans begins his road to knighthood, and wins a shiny medal from the Nobel committee in 2007.

That’s it for this week. Next week, we’ll find out where ES cells come from and why there’s such a fuss about it.