Mitochondrial heteroplasmy in Control Region DNA of South American camelids

In the present work, polymerase chain reaction-single strand conformation polymorphism and sequencing were used to investigate the length and nucleotide variability in the Control Region mitochondrial DNA of the four South American camelid species from Argentina. To asses these the complete Control Region of 20 animals, 5 each of guanaco, llama, alpaca and vicuña species were cloned. Seventy-three clones corresponding to the 20 animals were screened and 7 different SSCP patterns were identified. Sequencing of all clones showed 9 different haplotypes contained in the 350 bp hypervariable segment of the Control Region. Interestingly, 3 guanacos, 3 vicuñas, 3 alpacas and 1 llama were heteroplasmic for different nucleotide positions. The screening of the Control Region mitochondrial DNA in blood samples from about 200 wild guanacos from Argentine Patagonia supported the above results. After comparison with other vertebrate species, we concluded that nucleotide substitutions are the main cause of heteroplasmy found in Control Region mitochondrial DNA of these taxa.