Table 1.

Number of in utero transplanted animals with grafts containing healthy cells over all animals sacrificed during the post transplant time interval (days) indicated in the first column.

Days post natal	No. of surviving grafts/grafted mice	No. of independent mother mice	No. of surviving grafts/grafted rat	No. of independent mother rats
0–34	6/14	4	2/3	3
35–75	0/11	3	0/6	2
76–365	0/13	4	0/1	1
366–577	0/25	5	0/15	2

For each time interval the third and fifth columns indicate the number of independent pregnant female mice or female rats mothers to the sacrificed transplanted animals of each species. Siblings coming from the same mother were sacrificed at different time points. Differences between graft survival according to animal age groups were highly statistically significant (mice: χ², 23.211; degrees of freedom (DF) 3, p < 0.0001; rats χ², 15.942; DF 3; p < 0.0012).