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Background: Tandem repeats (TRs) in the mitochondrial (mt) genome control region have been documented in a wide variety of vertebrate species. The mechanism by which repeated tracts originate and undergo duplication and deletion, however, remains unclear.Results: We analyzed DNA sequences of mt genome TRs (mtTRs) in the ridged-eye flounder (Pleuronichthys cornutus), and characterized DNA sequences of mtTRs from other vertebrates using the data available in GenBank. Tandem repeats are concentrated in the control regions; however, we found approximately 16.6% of the TRs elsewhere in the mt genome. The flounder mtTRs possess three motif types with hypervariable characteristics at the 3' end of the control region (CR).Conclusion: Based on our analysis of this larger dataset of mtTR sequences, we propose a novel model of Pause Melting Misalignment (PMM) to describe the birth and motif indel of tandem repeats. PMM is activated during a pause event in mitochondrial replication in which a dynamic competition between the nascent (N) heavy strand and the displaced (D) heavy strand may lead to the melting of the N-strand from the template (T) light strand. When mispairing occurs during rebinding of the N-strand, one or several motifs can be inserted or deleted in both strands during the next round of mt-replication or repair. This model can explain the characteristics of TRs in available vertebrate mt genomes. © 2013 Shi et al; licensee BioMed Central Ltd.
Shi, W., Kong, X. Y., Wang, Z. M., Yu, S. S., Chen, H. X., & De Stasio, E. A. (2013). Pause-melting misalignment: A novel model for the birth and motif indel of tandem repeats in the mitochondrial genome. BMC Genomics, 14(1). https://doi.org/10.1186/1471-2164-14-103