Figure 3.

Competition between self- and non–self-mtDNA under nonselective conditions for respiratory function. 143B or Δ16.10.40 cells containing a zeocin resistance marker were fused to HG13 cells (harboring human nDNA and gorilla mtDNA) containing a neomycin resistance marker. Six of the resulting hybrids from each fusion resistant to both zeocin and the neomycin analogue G418 were isolated in complete medium supplemented with uridine. DNA was extracted from these hybrid clones and parental lines, digested with PvuII, and analyzed by Southern blot using a ³²P-labeled gorilla D-loop mtDNA region as a probe. The human samples showed the expected band corresponding to the 16.6-kb linearized mtDNA. The gorilla mtDNA was digested into the expected 10.5-kb fragment and three smaller fragments that were not detected by the probe. Note that none of the 12 zeo-neo hybrids retained the gorilla mtDNA.