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/10.1186/1471-2164-15-75102266nas a2200241 4500008004100000022001400041245009500055210006900150300001400219490000700233520143900240653002501679653002501704653002501729100001701754700001801771700001801789700001801807700001601825700002401841700001601865856014301881 2013 eng d a0253-977200aUnderstanding mitochondrial genome fragmentation in parasitic lice (Insecta: Phthiraptera)0 aUnderstanding mitochondrial genome fragmentation in parasitic li a847 - 8550 v353 a

Paper written in Chinese, Title: 虱 目裂 化 线 粒 体 基 因组 研 究 进 展

Abstract: Lice are obligateectoparasites of mammals and birds. Extensiver fagmentation of mitochondrial genomes has been found in some louse  species in the families Pediculidae,Pthiridae,Philopteridae and Trichodectidae. For example, the mt genomes of human body louse ( Pediculus humanus), head louse (Pediculus humanus capitis), and pubic louse (Pthirus pubis) have 20, 20 and 14 mini-chromosomes,respectively.These mini-chromosomes might be the results of deletion and recombination of mt genes .The factors and mechanism s of mitochondrial genome fragmentation are currently unknown. The fragmentation might be the results of evolutionary selection or random genetic drift or it is probably related to the lack of mtSSB (mitochondrial single-strand DNA binding protein).Understanding the fragmentation of mitochondrial genomes is  of significance for understanding the origin and evolution of mitochondria. This paper reviews the recent advances in the studies of mitochondrial genome fragmentation in lice, including the phenomena of mitochrondrial genome fragmentation, characteristics of fragmentated mitochondrial genomes, and some factors and mechanism possibly leading to the mitochondrial genome fragmentation of lice.Perspectives for future studies on fragmented mt genomes arealso discussed.

10aChromosome evolution10agenome fragmentation10aMitochondrial genome1 aDong, Wen-ge1 aGuo, Xian-guo1 aJin, Dao-chao1 aXue, Shi-peng1 aSong, Simon1 aBarker, Stephen, C.1 aShao, Renfu uhttps://www.researchgate.net/publication/249321853_Understanding_mitochondrial_genome_fragmentation_in_parasitic_lice_Insecta_Phthiraptera02401nas a2200229 4500008004100000245017600041210006900217260001600286300001400302490000600316520161200322653002501934653001201959653001901971653002501990653001802015100001602033700001102049700002402060700001602084856007102100 2017 eng d00aThe Mitochondrial Genome of the Guanaco Louse, Microthoracius praelongiceps: Insights into the Ancestral Mitochondrial Karyotype of Sucking Lice (Anoplura, Insecta)0 aMitochondrial Genome of the Guanaco Louse iMicrothoracius praelo cMar-23-2017 a431 - 4450 v93 a

Fragmented mitochondrial (mt) genomes have been reported in 11 species of sucking lice (suborder Anoplura) that infest humans, chimpanzees, pigs, horses, and rodents. There is substantial variation among these lice in mt karyotype: the number of minichromosomes of a species ranges from 9 to 20; the number of genes in a minichromosome ranges from 1 to 8; gene arrangement in a minichromosome differs between species, even in the same genus. We sequenced the mt genome of the guanaco louse, Microthoracius praelongiceps, to help establish the ancestral mt karyotype for sucking lice and understand how fragmented mt genomes evolved. The guanaco louse has 12 mt minichromosomes; each minichromosome has 2–5 genes and a non-coding region. The guanaco louse shares many features with rodent lice in mt karyotype, more than with other sucking lice. The guanaco louse, however, is more closely related phylogenetically to human lice, chimpanzee lice, pig lice, and horse lice than to rodent lice. By parsimony analysis of shared features in mt karyotype, we infer that the most recent common ancestor of sucking lice, which lived ~75 Ma, had 11 minichromosomes; each minichromosome had 1–6 genes and a non-coding region. As sucking lice diverged, split of mt minichromosomes occurred many times in the lineages leading to the lice of humans, chimpanzees, and rodents whereas merger of minichromosomes occurred in the lineage leading to the lice of pigs and horses. Together, splits and mergers of minichromosomes created a very complex and dynamic mt genome organization in the sucking lice.

10agenome fragmentation10aguanaco10aminichromosome10aMitochondrial genome10asucking lice.1 aShao, Renfu1 aLi, Hu1 aBarker, Stephen, C.1 aSong, Simon uhttps://academic.oup.com/gbe/article-lookup/doi/10.1093/gbe/evx00701880nas a2200193 4500008004100000245013400041210006900175260001600244300000900260490000600269520125800275100001601533700002401549700001101573700001601584700002801600700001301628856004501641 2015 eng d00aFragmented mitochondrial genomes in two suborders of parasitic lice of eutherian mammals (Anoplura and Rhynchophthirina, Insecta)0 aFragmented mitochondrial genomes in two suborders of parasitic l cJun-15-2015 a11pp0 v53 a

Parasitic lice (order Phthiraptera) infest birds and mammals. The typical animal mitochondrial (mt) genome organization, which consists of a single chromosome with 37 genes, was found in chewing lice in the suborders Amblycera and Ischnocera. The sucking lice (suborder Anoplura) known, however, have fragmented mt genomes with 9–20 minichromosomes. We sequenced the mt genome of the elephant louse, Haematomyzus elephantis – the first species of chewing lice investigated from the suborder Rhynchophthirina. We identified 33 mt genes in the elephant louse, which were on
10 minichromosomes. Each minichromosome is 3.5–4.2 kb in size and has 2–6 genes. Phylogenetic analyses of mt genome sequences confirm that the elephant louse is more closely related to sucking lice than to the chewing lice in the Amblycera and Ischnocera. Our results indicate that mt genome fragmentation is shared by the suborders Anoplura and Rhynchophthirina. Nine of the 10 mt minichromosomes of the elephant louse differ from those of the sucking lice (Anoplura) known in gene content and gene arrangement, indicating that distinct mt karyotypes have evolved in Anoplura and Rhynchophthirina since they diverged ~92 million years ago.

1 aShao, Renfu1 aBarker, Stephen, C.1 aLi, Hu1 aSong, Simon1 aPoudel, Shree, Kanta S.1 aSu, Yuan uhttp://www.nature.com/articles/srep17389