Creating a clone library is important for just one reason: so that you can find your clones when you need them.

May be your colleague wants to continue your project, or you publish the results and somebody requests your clone.

In times like that it is very satisfying to know where your clones are.

Protocol for creating clone library:
• Create an Excel or a Word file with library information
• For each clone, prepare two tubes with clone name and number
• Add 0.9 ml of overnight E.coli culture and 0.1 ml of DMSO to one of the tubes, store at -80 oC
• Put plasmid DNA into another tube, store at -20 oC

I keep the information about my clone library in an Excel spreadsheet.

I assign each of my clones a number, which is stored in the Excel file along with clone name, description, name of the parental vector, date created, primer names, and whatever other information I find relevant.

For each clone, I prepare two 2 ml screw cup tubes with clone name and number. I am going to put the DNA into one of the tubes, entire 100 µl isolated with the miniprep kit.

And in the second tube I will put the E.coli culture, the one that we saved earlier today, right before starting the miniprep protocol.

In this case I will use 900 µl of E.coli culture, and in addition I will add 100 µl of dimethyl sulfoxide, or DMSO, which will serve as a cryoprotectant for the E.coli cells. Here is the original DMSO bottle, and here is an aliquot that I use on every day basis.

I will mix E.coli with DMSO by flipping over the tubes a couple of times. I will put the 2 ml library tubes into two boxes that I prepared here: a -80 oC box for E.coli and a -20oC box for DNA.
The DNA box goes into -20 oC freezer. And the E.coli culture box goes into -80 oC freezer.