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Open Access Research article

A novel model of double replications and random loss accounts for rearrangements in the Mitogenome of Samariscus latus (Teleostei: Pleuronectiformes)

Wei Shi, Xian-Guang Miao and Xiao-Yu Kong*

Author Affiliations

CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, People's Republic of China

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BMC Genomics 2014, 15:352  doi:10.1186/1471-2164-15-352

Published: 9 May 2014

Abstract

Background

Although more than one thousand complete mitochondrial DNA (mtDNA) sequences have been determined in teleostean fishes, only a few gene rearrangements have been observed, and genome-scale rearrangements are even rarer. However, flatfishes (Pleuronectiformes) have been identified as having diverse types of mitochondrial gene rearrangements. It has been reported that tongue soles and the blue flounder mitogenomes exhibit different types of large-scale gene rearrangements.

Results

In the present study, the complete mitochondrial genome of another flatfish, Samariscus latus, was sequenced, and genome-scale rearrangements were observed. The genomic features of this flounder are different from those of any other studied vertebrates, including flatfish species too. The mitogenome of S. latus is characterized by the duplication and translocation of the control region (CR). The genes located between the two CRs are divided into two clusters in which their relative orders are maintained.

Conclusions

We propose a “Double Replications and Random Loss” model to explain the rearrangement events in S. latus mitogenome. This model consists of the following steps. First, the CR was duplicated and translocated. Subsequently, double replications of the mitogenome were successively initiated from the two CRs, leading to the duplication of the genes between the two CRs. Finally, one of each pair of duplicated genes was lost in a random event.

Keywords:
Flatfish; Flounder; Mitochondrial recombination; Gene order; Molecular rvolution