Mitochondrial DNA The Journal of DNA Mapping, Sequencing, and Analysis

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The complete mitochondrial genome of Bombyx mori strain Yu5 (Lepidoptera: Bombycidae) Yong-Liang Zhang, Jin-Hui Zhao & Qi-Ming Zhou To cite this article: Yong-Liang Zhang, Jin-Hui Zhao & Qi-Ming Zhou (2015): The complete mitochondrial genome of Bombyx mori strain Yu5 (Lepidoptera: Bombycidae), Mitochondrial DNA To link to this article: http://dx.doi.org/10.3109/19401736.2014.1003876

Published online: 28 Jan 2015.

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Date: 05 November 2015, At: 16:59

http://informahealthcare.com/mdn ISSN: 1940-1736 (print), 1940-1744 (electronic) Mitochondrial DNA, Early Online: 1–2 ! 2015 Informa UK Ltd. DOI: 10.3109/19401736.2014.1003876

MITOGENOME ANNOUNCEMENT

The complete mitochondrial genome of Bombyx mori strain Yu5 (Lepidoptera: Bombycidae) Yong-Liang Zhang1, Jin-Hui Zhao1, and Qi-Ming Zhou2 College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou City, Henan Province, China and 2Sericultural Science Research Institute of Henan Province, Nanyang City, Henan Province, China

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Abstract

Keywords

The complete mitochondrial genome of Bombyx mori strain Yu5 (Lepidoptera: Bombycidae) is a circular molecule of 15,644 bp in length, containing 37 typical coding genes and one noncoding AT-rich region. The overall composition of the mitogenome was A (43.07%), G (7.34%), C (11.33%), and T (38.26%). Its gene order and content were identical to the common type found in most insect mitogenomes. All protein coding genes (PCGs) started with a typical ATN initiation codon, except for the cox1 gene, which began with CGA codon. Eleven genes used standard complete termination codon TAA, whereas the cox1 and cox2 genes ended with single T. All tRNA genes displayed typical secondary cloverleaf structures as those of other insects. Additionally, the 494 bp long AT-rich region contained several structures common to the other lepidopterons, such as some structures of repeated motifs and microsatellite-like elements and a poly-A element upstream of transfer RNA M (trnM) gene.

Bombyx mori Yu5, insect, mitogenome, silkworm

Mitochondrial DNA (mtDNA) can be used as molecular marker for evolutionary studies since it is maternally inherited DNA with a rapid evolutionary rate and lacks genetic recombination (Wolstenholme, 1992).To date, more than 240 species of the complete or nearly complete mitogenome sequences from insects have been determined based on the GenBank database. Although the Lepidoptera is the second largest order of insects, only about more than 30 complete or near-complete mitogenomes are currently available in GenBank. Currently, only four complete mitogenomes of species of Bombycidae have been reported, including Bombyx mori Xiafang (Lu et al., 2002), B. mori C108 (Yukuhiro et al., 2002), Bombyx mori Dazao (Liu et al., 2013), B. mori strain H9 (Dai et al., 2013). In this article, we determined the complete mitogenome sequence of B. mori strain Yu5, in order to provide more useful information for the taxonomic and phylogenetic studies of B. mori. The new sequence of this whole mtDNA genome was deposited in GenBank with the accession number KP192479. The complete mtDNA sequence of B. mori strain Yu5 (15,644 bp in length) has typical 13 protein-coding genes, 22 tRNA genes, two rRNA genes (rrnL and rrnS), and 1 non-coding AT-rich region (Table 1). Its gene order and orientation are identical to those of sequenced lepidopteran mitogenomes. Besides the AT-rich region, 20 intergenic spacers (364 bp in total) and five overlapping regions (20 bp in total) are dispersed throughout the whole

History Received 3 December 2014 Accepted 5 December 2014 Published online 28 January 2015

genome. The base composition of the genome is A (43.07%)4T (38.26%)4C (11.33%)4G (7.34%), and the A–T bias (81.33%) was detected, which is well within the range of other sequenced lepidopteran, from 79.7% in Pieris rapae (Mao et al., 2010) to 82.2% in Drosophila melanogaster (de Bruijn, 1983). All PCGs are initiated by a typical ATN codon, except for the cox1 gene, which uses CGA codon as observed in the sequenced Bombycidae (Lu et al., 2002). Eleven PCGs have a complete termination codon TAA and the incomplete stop codons (T-) are found in the other two genes (cox1 and cox2) (Table 1). The 22 tRNA genes ranging in size from 62 bp to 71 bp displayed the typical clover-leaf secondary structure observed in mitochondrial tRNA genes from several lepidopteran and metazoan insects (Dai et al., 2013; Wolstenholme, 1992). The two rRNAs (1378 bp rrnL and 783 bp rrnS) are also significantly biased towards A and T nucleotides (84.40% for rrnL and 85.57% for rrnS, respectively). The 494 bp AT-rich region is located between the rrnS gene and the trnM gene cluster and exhibits the highest AT content (94.94%) among the whole genome, which is within the range reported for other lepidopteran insects (Cameron et al., 2008; Pan et al., 2008; Yang et al., 2009; Yukuhiro et al., 2002). Several characteristic structures are also detected in the AT-rich region, such as the ATAGA motif followed by an 18 bp poly-T stretch and the ATTTA motif followed by two microsatellite-like (AT)8 and (AT)8 element and an 11 bp poly-A element upstream of transfer RNA M (trnM) gene.

Correspondence: Yong-Liang Zhang, College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou City, Henan Province, China. Email: [email protected]

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Y.-L. Zhang et al.

Mitochondrial DNA, Early Online: 1–2

Table 1. Summary of the mitogenome of Bombyx mori strain Yu5.

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Gene trnM trnI trnQ nad2 trnW trnC trnY cox1 trnL2(UUR) cox2 trnK trnD atp8 atp6 cox3 trnG nad3 trnA trnR trnN trnS1(AGN) trnE trnF nad5 trnH nad4 nad4L trnT trnP nad6 cob trnS2(UCN) nad1 trnL1(CUN) rrnL trnV rrnS Control region

Direction

Location

Size

Anticodon

Start codon

Stop codon

F F R F F R R F F F F F F F F F F F F F F F R R R R R F R F F F R R R R R

1–64 65–130 128–196 263–1267 1273–1342 1336–1400 1410–1471 1489–3019 3020–3086 3087–3768 3769–3839 3838–3905 3906–4067 4061–4738 4753–5541 5544–5609 5613–5963 6004–6071 6104–6167 6169–6235 6236–6302 6320–6385 6386–6450 6456–8174 8202–8268 8307–9659 9659–9949 9954–10,018 10,019–10,084 10,087–10,617 10,666–11,817 11,821–11,886 11,912–12,844 12,851–12,921 12,922–14,299 14,300–14,367 14,368–15,150 15,151–15,644

64 66 69 1005 70 65 62 1531 67 682 71 68 162 678 789 66 351 68 64 67 67 66 65 1719 67 1353 291 65 66 531 1152 66 933 71 1378 68 783 494

CAT30–32 GAT94–96 TTG164–166 – TCA1304–1306 TGC1371–1373 GTA1440–1442 – TAA3050–3052 – CTT3799–3801 GTC3870–3872 – – – TCC5574–5576 – TGC6036–6038 TCG6133–6135 GTT6200–6202 GCT6262–6264 TTC6350–6352 GAA6416–6418 – TGA8236–8238 – – TGT9985–9987 TGG10052–10054 – – TGA11851–11853 – TAG12889–12891 – TAC14334–14336 – –

– – – ATA – – – CGA – ATG – – ATA ATG ATG – ATA – – – – – – ATT – ATG ATG – – ATT ATA – ATT – – – – –

– – – TAA – – – T – T – – TAA TAA TAA – TAA – – – – – – TAA – TAA TAA – – TAA TAA – TAA – – – – –

Declaration of interest The authors report that they have no conflicts of interest. The authors alone are responsible for the content and writing of the article. This work was supported by the National Natural Science Foundation of China (31271627) and the Key Discipline Construction Fund Project of Zhoukou Normal University.

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