How do you know your lab mate had been breeding his mice? You smell him from afar…No joke, working in the animal house with mice, rats or rabbits is a smelly business. Let’s just say you’ll want to keep your visits to a minimum, if possible.
In-vivo experimentation is one of the major platforms on which the immunology, physiology and neurobiology niche depend upon. Working with a mammalian creature demands paying great deal of attention to details, intricate hands capabilities, well planned experiments and well ordered documentation of the different strains, injected mice and ongoing experimentation. A regular experiment can last between one to six months (and sometime much longer), making a mistake at the setup stage can cost A LOT of time (and frustration!).
Breed With Care
Due to the complexity of the genetic background of each mice strain, it’s highly important to make sure you are working with the correct strain, especially if your lab has various sub strains, crosses and knockout mice. If you are not sure about a specific strain (and there is no proper documentation) it is better to conduct a PCR on DNA derived from a blood sample/tail of the mice with specific primers aimed at the site of mutation/KO/SNPs (these are always available in the strain article). Make sure you document all the genetic background of each strain in your notebook for references purposes (future publications or other lab members working with specific strains).
Using BioKM’s collection module can enhance detailing and sharing of the relevant data across the lab members easy and at a couple of clicks away. With this module you can custom tailor your different characteristics that are relevant to the mice strain your are breeding. If you have any doubts, you can always send your PI a message with a specific link to a strain and s/he can update the required info right there without the need to leave the chair.
Basic breeding scheme should take into account the following:
- You should maintain at least two generations at reproduction age (8 to 32 week old mice) for each strain.
- Maintain at least six mating pairs in case some mice get ill, show reduced breeding etc.
- Backcross every 10 generation to reduce genetic drift (or order mice from Jax laboratories)
- Expected experiment needs – this should be planned 2-3 months earlier, depending on your mice needs. Generally 5-6 mice per one experiment set (such as injection of a compound) and a similar number for the control should be used for better statistical significance of established results.
- Plan your cage usage/breeding scheme according to approximately 1 liter/month when housing 2-3 mating cages (one male per female), which will generate between 6 to 8 pups. Don’t forget that a cage can cost you around 10-40 USD/day, depending on the facilities used.
- While females can be housed together across all ages, males should be housed only when they are littermates.
In my next post, I’ll discuss marking and documenting your mouse colony, immunizations, and phenotype monitoring.