| January 26, 2010 |
Germline Competency: What Does it Mean and How is it Determined?
Is There an Absolute Guarantee?
Germline competency, the ability of a mouse ES cell line to successfully contribute to germ cell formation and transmit targeted genes to progeny, is a very important and desirable feature of an mES cell line. As of January 2010, we offer 10 lines of JAX® mES cells. JAX scientists have confirmed the germline competency of four lines, and the germline competency of the NOD line was confirmed in the laboratory of Rudolf Jaenisch at MIT. JAX scientists are currently testing the germline competency of the other five lines and of stocks of NOD ES cells expanded on site.
Germline competency is often difficult to predict. It is typically evaluated by breeding a chimeric mouse that harbors a targeted mutation to a wild-type mouse and genotyping the offspring for the presence of the targeted gene. Factors that may reduce the probability of germline competency include the following:
- The passage number of the ES cell line (earlier passages typically have higher germline competency because they are more likely to have a higher percentage of cells with a normal karyotype – i.e., fewer chromosomal gains, losses, or translocations)
- The amount of stress imposed on the ES cell population by culture methods and the gene targeting process
Even after all factors are considered and all quality control protocols are followed, a supplier can only state the probability of an mES cell line being germline competent. Given the number of variables that can affect germline competency, our goal is to provide you with high quality, low passage mES cells so you can begin your research as soon as possible. We will provide results of germline competency trials as they become available.
