Transgenic offspring by transcaryotic implantation of transgenic ovaries into normal mice.

Female transgenic mice may be unable to reproduce successfully if the product encoded by the transgene results in pathological changes or affects the fertility of the mouse. To approach this problem, we have produced chimaeras by transferring the ovaries of transgenic mice into normal mice of the same strain. Such chimaeras will be an ideal tool for investigating the interactions between transgenic ovaries and normal mice or vice versa.

Monozygotic vs. dizygotic twin behavior in artificial mouse twins.

Adult inbred mice of an isogenic strain (AKR/NHan or C57BL/6J Han) differ in social (sexual and agonistic), emotional and psychomotoric behavior, depending on the kind of manipulation to which they were subjected at an early ontogenetic stage. Monozygotic twins (MZT) from eight-cell stages halved and transferred to uterine foster mothers were compared with dizygotic twins (DZT) from nonreduced but transferred eight-cell stages and with naturally born animals (NBA). Generally, early embryonic conditions predict the behavioral characteristics of the adult animals to a high degree.

Strain differences in kidney function of inbred rats: 1. Glomerular filtration rate and renal plasma flow.

Bodyweight, kidney weight and glomerular filtration rate showed significant differences between strains--70% of the total variance was ascribed to the between-strain variance component--while the renal plasma flow showed only a slight strain difference due to a high within-strain variance component (63%). Heritability in the broad sense was 0.78 for bodyweight, 0.