Repositories have an essential function to secure and maintain the investment in the resource for future generations of scientists. Repositories have the obligation to ensure and preserve the quality of the resource and to act as honest brokers with efficient, unrestricted, and unencumbered distribution to third-party users.
The distribution of IKMC vectors and ES cells takes place through several repositories in Europe, the US, and Canada (EuMMCR, KOMP, TIGM, and CMMR, Tables 2, 3). The repositories conduct stringent quality control on the vectors and ES cell clones prior to distribution to ensure the integrity of each allele. They currently distribute nonoverlapping sectors of the IKMC resource to a global user group. Altogether, these centers have already distributed 1,029 targeting vectors and 4,126 mutant ES cell alleles.
The IKMC mice are distributed through EMMA, MMRRC/KOMP, TIGM, and CMMR, the European, US, and Canadian mouse repositories, respectively (Tables 2, 3). To date, of the 1,709 mutated mouse lines, 1,107 (65 %) have been distributed outside of the center in which they were initially produced (Table 2). The dominant impact of IKMC resources on the activity of these repositories is already apparent, e.g., more than 50 % of mice distributed by EMMA were derived from IKMC resources. IKMC mice are also being generated and analyzed in distributed activities by hundreds of individual specialist laboratories worldwide, which to date have cumulatively received 4,126 mutant ES cell alleles from the repositories.
In summary, to date already 6,262 mutant alleles have been distributed worldwide as vectors, ES cells, or mice (about 35 % of IKMC alleles available), and the international requests are still increasing.