Those of you who follow me on Twitter may have sensed a disturbance in the Force earlier in the week. The lab I work in does a great deal of in vivo work using an array of different transgenic and knockout animals. Typically we have a tech who maintains strains–mostly controls–that multiple people in the lab use. Other strains are the responsibility of the trainee who will be the primary user. About a year ago, we obtained a strain from a biotech/pharma company for a new direction of our work. A fellow in the lab was given responsibility of the strain, which was then transferred to another fellow, and ultimately transferred to me a few months ago. Coming from a biochemistry lab, I had absolutely no experience working with mice or maintaining strains, which I made clear to all parties involved and asked for help along the way. It was the understanding of the tech and other postdoc that the deletion was stable, the breeders were homozygous deficient, and thus there was no need for genotyping. So I proceeded under this presumption.
Perhaps you see where this is going.
Someone in the lab wanted to use these mice for another project. At this point, we needed to check the genetic background for the strain. There is a handful of inbred lines that are commonly used for manipulating the genome and maintaining strains. Different inbred lines are not genetically identical; in fact, the same strain inbred at different companies may not even be genetically identical. Genetic differences between strains can translate into widely varying responses in your disease model of choice. So it’s kind of important to know your background. When I asked for some sort of documentation on this strain, our tech produced a health report sent from the company, and on the report, the background was listed as FVB/N. So we bought this strain and have been breeding them for about 6 months or so.
When I started doing in vivo work a few months ago, I realized something was a little odd. FVB/N mice are white and fluffy. The knockouts were sleek and black. I brought this up with another fellow and essentially was told not to worry about it. Sometimes these things happen–maybe it’s an artifact from the backcross. Blah, blah, whatever. Moving on.
I was a planning a pretty big experiment with these knockouts this week. But that little niggling doubt just wouldn’t go away. So I emailed the fellow that initially received the mice–he had nothing. Then I started tracking back through our breeding records–and dead ended at the mice from the company. I took a closer look at the health report that had been produced previously and realized that (a) the mice on it were way too old to have been the ones we initially received and (b) they were all female. Where was the info for the males? Clearly there were males in my breeding cages because they were producing litters. With some help from our trusty lab admin, I was able to contact the company’s vet manager, who emailed me the info they had on record within an hour–informing me that the strain was on a B6 background and that they had sent us 2 males and 2 females… all heterozygous for the mutation.
That was the point that my head almost exploded. Not only did we have the background wrong, we had the genotype wrong. I promptly requested a genotyping protocol, received one almost immediately, and got to work sorting out this little clusterfuck. Fortunately Mendelian inheritance seemed to prevail, and even though we no longer had the original breeders, I still had a mix of +/+, +/-, and -/- mice. All was not lost as I had feared.
Even so, all this meant:
- I spent approximately 1.7 days sorting out this mess instead of doing other experiments I had planned for the week.
- Results from the handful of experiments this strain had been used for have to be thrown out since we have no idea what genotype those mice were.
- We bred and maintained a strain of mice for 6 months that we never needed.
- I will be waiting a minimum of 8 weeks to the experiment planned for the knockout strain.
So what’s the lesson here?
Be careful what information you trust. And be sure that you have solid documentation of what you have. Documentation and records management is something that, in my experience, most academic labs really suck at. Don’t be afraid to push a little to get documentation, even if multiple people relay the information verbally–they might know or they might simply be repeating what someone else has said. You might think that as a grad student or postdoc, you’re here to do research–it’s not really your job to track down records. Make it part of your job. It will save you tremendous headaches and lost time down the road.