02632nas a2200253 4500008004100000022001400041245024200055210006900297260001200366300000700378490000700385520171600392653002502108653002502133653001902158653002502177653001702202100001702219700001602236700001802252700001802270700001602288856007402304 2014 eng d a1471-216400aFragmented mitochondrial genomes of the rat lice, Polyplax asiatica and Polyplax spinulosa: intra-genus variation in fragmentation pattern and a possible link between the extent of fragmentation and the length of life cycle0 aFragmented mitochondrial genomes of the rat lice iPolyplax asiat c01-2014 a440 v153 a

Background: Blood-sucking lice (suborder Anoplura) parasitize eutherian mammals with 67% of the 540 described species found on rodents. The five species of blood-sucking lice that infest humans and pigs have fragmented mitochondrial genomes and differ substantially in the extent of fragmentation. To understand whether, or not,
any life-history factors are linked to such variation, we sequenced the mt genomes of Polyplax asiatica and Polyplax spinulosa, collected from the greater bandicoot rat, Bandicota indica, and the Asian house rat, Rattus tanezumi, respectively.
Results: We identified all of the 37 mitochondrial genes common to animals in Polyplax asiatica and Polyplax spinulosa. The mitochondrial genes of these two rat lice are on 11 circular minichromosomes; each minichromosome is 2–4 kb long and has 2–7 genes. The two rat lice share the same pattern for the distribution of the protein-coding genes and ribosomal RNA genes over the minichromosomes, but differ in the pattern for the distribution of 8 of the 22 transfer RNA genes. The mitochondrial genomes of the Polyplax rat lice have 3.4 genes, on average, on each minichromosome and, thus, are less fragmented than those of the human lice (2.1 and 2.4 genes per minichromosome), but are more fragmented than those of the pig lice (4.1 genes per minichromosome).
Conclusions: Our results revealed distinct patterns of mitochondrial genome fragmentation within the genus Polyplax and, furthermore, indicated a possible inverse link between the extent of mitochondrial genome fragmentation and the length of life cycle of the blood-sucking lice.

10aChromosome evolution10agenome fragmentation10aminichromosome10aMitochondrial genome10asucking lice1 aDong, Wen-ge1 aSong, Simon1 aJin, Dao-chao1 aGuo, Xian-guo1 aShao, Renfu uhttp://bmcgenomics.biomedcentral.com/articles/10.1186/1471-2164-15-4403098nas a2200277 4500008004100000022001400041245018300055210006900238260001400307300001000321490000700331520216800338653002502506653002502531653001902556653002502575653001702600100001702617700001602634700001802650700001802668700001902686700002402705700001602729856007502745 2014 eng d a1471-216400aFragmented mitochondrial genomes are present in both major clades of the blood-sucking lice (suborder Anoplura): evidence from two Hoplopleura rodent lice (family Hoplopleuridae)0 aFragmented mitochondrial genomes are present in both major clade cSept-2014 a13 pp0 v153 a

Background: The suborder Anoplura contains 540 species of blood-sucking lice that parasitize over 840 species of eutherian mammals. Fragmented mitochondrial (mt) genomes have been found in the lice of humans, pigs, horses and rats from four families: Pediculidae, Pthiridae, Haematopinidae and Polyplacidae. These lice, eight species in total, are from the same major clade of the Anoplura. The mt genomes of these lice consist of 9–20 minichromosomes; each minichromosome is 1.5–4 kb in size and has 1–8 genes. To understand mt genome fragmentation in the other major clade of the Anoplura, we sequenced the mt genomes of two species of rodent lice in the genus Hoplopleura (family Hoplopleuridae).
Results: We identified 28 mt genes on 10 minichromosomes in the mouse louse, Ho. akanezumi; each minichromosome is 1.7–2.7 kb long and has 1–6 genes. We identified 34 mt genes on 11 minichromosomes in the rat louse, Ho. kitti; each minichromosome is 1.8–2.8 kb long and has 1–5 genes. Ho. akanezumi also has a chimeric minichromosome with parts of two rRNA genes and a full-length tRNA gene for tyrosine. These two rodent lice share the same pattern for the distribution of all of the protein-coding and rRNA genes but differ in tRNA gene content and gene arrangement in four minichromosomes. Like the four genera of blood-sucking lice that have been investigated in previous studies, the Hoplopleura species have four minichromosomes that are only found in this genus.
Conclusions: Our results indicate that fragmented mt genomes were present in the most recent common ancestor of the two major clades of the blood-sucking lice, which lived ~75 million years ago. Intra-genus variation in the pattern of mt genome fragmentation is common in the blood-sucking lice (suborder Anoplura) and genus- specific minichromosomes are potential synapomorphies. Future studies should expand into more species, genera and families of blood-sucking lice to explore further the phylogenetic utility of the novel features associated with fragmented mt genomes.

10aChromosome evolution10agenome fragmentation10aminichromosome10aMitochondrial genome10asucking lice1 aDong, Wen-ge1 aSong, Simon1 aGuo, Xian-guo1 aJin, Dao-chao1 aYang, Qianqian1 aBarker, Stephen, C.1 aShao, Renfu uhttp://bmcgenomics.biomedcentral.com/articles/10.1186/1471-2164-15-751