Mitochondrial DNA (mtDNA) marked widely used in evolutionary studies, especially in studies on human evolutionary history. At present, a large number of mtDNA genome sequences have submitted to public databases, but the quality of the data is not always perfect. Recent studies on the quality of human mtDNA found that sample contamination and sequencing errors exist, and such errors are not infrequent, negatively impacting the data analyses using these sequences.

While some work has been done on surveying the quality of human mtDNA, it was unclear to what extent sequencing problems persisted in domestic animal mtDNA samples. Recently, Ya-Ping Zhang’s group at the Kunming Institute of Zoology Chinese Academy of Science (KIZ, CAS) systematically evaluated 1342 mtDNA genome sequences from 8 types of domestic animals: dogs, cattle, yak, pigs, horses, goats, sheep and chickens.

Using phylogenetics to examine the sequencing quality of these samples, Zhang’s group found 194 sequencing errors (14.5%) that impacted the quality of the data—most errors being attributable to artificial recombination, surplus of mutations, and phantom mutations. The results suggest domesticated animals mtDNA sequences submitted to public databases should be used with some caution to avoid compromising the analyses and conclusions of research done on domesticated animals. More importantly, Zhang’s research showed that regardless of the sample—human or animal—it is critical to adopt strict quality control measures.

The full study was published in Molecular Ecology, available here: http://onlinelibrary.wiley.com/doi/10.1111/mec.12955/abstract

(By Andrew Willden)