Table 2. Lethality of the mouse embryos harbouring bovine mitochondria at the early postimplantation stage.

	No. of recipients	No. of blastocysts transferred	No. of implantation sites(% ± SEM)	No. of viable foetuses(% ± SEM)
non-manipulated	4	38	24 (63.2 ± 9.2)	15 (39.5 ± 11.7)
mtM-M	3	30	22 (73.3 ± 3.3)	8 (26.7 ± 3.3)
mtB-M	7	51	0 (0.0 ± 0.0)	0 (0.0 ± 0.0)

mtM-M: mouse embryos with mitochondria derived from another mouse. mtB-M: mouse embryos with bovine mitochondria.