Complete mitogenome of Anopheles sinensis and mitochondrial insertion segments in the nuclear genomes of 19 mosquito species

Bo Li,Y-h. Taguchi,Yi-Ran Ding,Bin Chen,Yu-Juan Zhang,Qi-Meng Mao

doi:10.1371/journal.pone.0204667

Abstract

Anopheles sinensis is a major malarial vector in China and Southeast Asia. The mitochondria is involved in many important biological functions. Nuclear mitochondrial DNA segments (NUMTs) are common in eukaryotic organisms, but their characteristics are poorly understood. We sequenced and analyzed the complete mitochondrial (mt) genome of An. sinensis. The mt genome is 15,418 bp long and contains 13 protein-coding genes (PCGs), two rRNAs, 22 tRNAs and a large non-coding region. Its gene arrangement is similar to previously published mosquito mt genomes. We identified and analyzed the NUMTs of 19 mosquito species with both nuclear genomes and mt genome sequences. The number, total length and density of NUMTs are significantly correlated with genome size. About half of NUMTs are short (< 200 bp), but larger genomes can house longer NUMTs. NUMTs may help explain genome size expansion in mosquitoes. The expansion due to mitochondrial insertion segments is variable in different insect groups. PCGs are transferred to nuclear genomes at a higher frequency in mosquitoes, but NUMT origination is more different than in mammals. Larger-sized nuclear genomes have longer mt genome sequences in both mosquitoes and mammals. The study provides a foundation for the functional research of mitochondrial genes in An. sinensis and helps us understand the characteristics and origin of NUMTs and the potential contribution to genome expansion.

Highlights

Mitochondria are eukaryotic cell organelles that are mainly involved in oxidative phosphorylation [1,2]
The mt genome sequence of An. sinensis contains a conserved set of 37 genes, including 13 protein-coding genes (PCGs), two rRNA genes, 22 tRNA genes and a large non-coding region (CR, known as the AT-rich region) (Fig 1)
The genome size expansion due to mitochondrial insertion segments is variable in different insect groups

Summary

Introduction

Mitochondria are eukaryotic cell organelles that are mainly involved in oxidative phosphorylation [1,2]. The conservation, easy alignment, maternal inheritance, and straightforward gene orthology of mitochondrial (mt) genomes have made the mt genome important for studies of phylogeny and evolution [3,4,5,6]. Mt genomes are sometimes associated with insecticide resistance. Several transcripts encoding enzymes such as NADH dehydrogenase and ATP synthase, which are involved in the production of energy within the respiratory chain, were overexpressed in Aedes aegypti larvae exposed to insecticides [7].

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Results

Conclusion