Physical characterization of mitochondrial DNA from cotton

Mitochondrial DNA from Gossypium hirsutum cv. Paymaster Glandless 784 was isolated from seedlings and further purified by treatment with ribonuclease and proteinase K followed by extraction with buffered phenol. The median thermal dissociation temperature (T sub(m)) of cotton mtDNA was determined by the thermal dissociation method of Marmur and Doty to be approximately 88.2 degree C. From this a GC content of 44.7% was calculated according to Mandel et al. The sigma 2/3 of the thermal denaturation curve indicated a homogeneous distribution of GC in the cotton mitochondrial genome.