Donor and recipient genotype and heterosis effects on survival and prenatal growth of transferred mouse embryos.

Reciprocal embryo transfers amongst two inbred strains (C3HeB/FeJ and SWR/J) and their F1 cross (C3SWF1) were used to examine donor and recipient genotype and heterosis effects on survival and prenatal growth of mouse embryos. Among inbred strains, significant recipient genotype effects were detected for both embryo survival (P less than 0.01) and prenatal growth (P less than 0.05), while no donor genotype effects were observed. The recipient effect on overall embryo survival was due to a higher proportion of C3H recipients maintaining pregnancy to term than SWR recipients (P less than 0.01), rather than survival within litters. Irrespective of their own genotype, embryos developing in C3H uteri achieved larger body weights (P less than 0.01) and longer tail lengths (P less than 0.05) at birth than did embryos developing in SWR uteri. Recipient heterosis was not significant, while donor heterosis was significant for prenatal growth traits (P less than 0.001).