Table 2. Mitochondrial DNA copy numbers derived from porcine oocyte and mouse donor cells at different developmental stages of mouse-porcine cloned embryos¹⁾

Stages	The mtDNA copy numbers		MFF/porcine oocyte mtDNA (%)
	Porcine oocyte mtDNA	MFF mtDNA
1-cell	1.1 × 106 ± 0.9 × 106	5.7 × 104 ± 0.3 × 105	5.0 ± 0.04
2-cell	9.3 × 105 ± 0.5 × 106	4.2 × 103 ± 1.0 × 103	0.5 ± 0.01
4-cell	6.6 × 105 ± 0.2 × 106	1.9 × 104 ± 0.6 × 104	2.9 ± 0.04
8-cell	1.3 × 106 ± 0.3 × 106	2.0 × 103 ± 1.1 × 103	0.2 ± 0.00
Morula	4.1 × 106 ± 0.8 × 106	2.5 × 104 ± 1.1 × 104	0.6 ± 0.01
Blastocyst	1.3 × 106 ± 0.2 × 106	1.3 × 102 ± 0.3 × 102	0.009 ± 0.01

Experiments were repeated four times.