DNA CONTENT DIFFERENCES IN LABORATORY MOUSE STRAINS DETERMINED BY FLOW-CYTOMETRY

The nuclear DNA content of seven mouse laboratory strains has been mea sured by flow cytometry. The differences observed between strains as w ell as those between sexes within the strain were all statistically si gnificant. The highest DNA content (approximately 6.4 pg/female nucleu s) was found in the Balb/c strain; the lowest (approximately 5.7 pg/ma le nucleus) in the C3H/he strain. The difference between sexes varied from 1.6% (in CD-1 mice) to 6.3% (in nude mice). The interest of these results is twofold. First, the mouse can now be used to study the ada ptive significance of genome size variation, so far studied only in. p lants. Second, DNA content analysis can become a quick method for mous e strain identification. (C) 1997 Wiley-Liss, Inc.