Why yeast? Part I

I volunteered to be the speaker at a Jr. Science Cafe in a couple weeks. The idea is that middle school and high school students will come and listen to me talk a little bit about science and we’ll have a discussion. My topic is using yeast as a model system. However, last night, I tried explaining to a layperson why we use yeast and I found myself floundering a little bit. Why do we use yeast?

Well, for one thing, it’s easy to work with. You don’t need a lot of special equipment. Just a regular incubator set at 30 degrees Celsius and a shaking incubator set at 30 degrees celsius. Another couple of incubators are good so that you can change the temperature for temperature sensitive mutants. And you can grow yeast on your benchtop as well–it just takes a little longer. Contrast that with mammalian tissue culture (mammalian cells grown in dishes). You need a special hood to maintain sterility. You need fancy incubators that pump carbon dioxide into them.

Yeast don’t take up a lot of space. You just need space for the incubators and glassware. Mice, another good models system, take up a lot of space. And you have to have a special facility in which to house them, special protocols for the care and treatment of the mice and how you are going to use them in your experiments. There are very specific rules about how you take care of animals that are used for research purposes. Even fish, which seem pretty straightforward, have special protocols for maintenance.  Nobody cares how we treat the yeast.

And yeast are cheap. All of those special facilities for animals cost a lot of money to maintain, money that has to come out of your grants. Even tissue culture is expensive. Because it’s so easy to contaminate your cells, you use lots of disposable pipets and bottles, unlike with yeast where everything is reusable once it’s been cleaned and sterilized. Also, tissue culture requires the cells to be grown in special media which is bought pre-made and is quite expensive. Yeast media is cheap and you can make it yourself.

So, yeast are convenient. But there’s more to yeast than convenience (see Why yeast? Part II).