TY - JOUR T1 - Frequent tRNA gene translocation towards the boundaries with control regions contributes to the highly dynamic mitochondrial genome organization of the parasitic lice of mammals JF - BMC Genomics Y1 - 2021 DO - 10.1186/s12864-021-07859-w A1 - Dong,Wen-ge A1 - Yalun Dong A1 - Guo,Xian-guo A1 - Renfu Shao SP - 16 pp KW - genome fragmentation KW - Microthoradus praelongiceps KW - Mitochondrial karyotype KW - Parasitic lice KW - Pediculus badii KW - tRNA translocation AB -

Background The typical single-chromosome mitochondrial (mt) genome of animals has fragmented into multiple minichromosomes in the lineage Mitodivisia, which contains most of the parasitic lice of eutherian mammals. These parasitic lice differ from each other even among congeneric species in mt karyotype, i.e. the number of minichromosomes, and the gene content and gene order in each minichromosome, which is in stark contrast to the extremely conserved single-chromosome mt genomes across most animal lineages. How fragmented mt genomes evolved is still poorly understood. We use Polyplax sucking lice as a model to investigate how tRNA gene translocation shapes the dynamic mt karyotypes.

Results We sequenced the full mt genome of the Asian grey shrew louse, Polyplax reclinata. We then inferred the ancestral mt karyotype for Polyplax lice and compared it with the mt karyotypes of the three Polyplax species sequenced to date. We found that tRNA genes were entirely responsible for mt karyotype variation among these three species of Polyplax lice. Furthermore, tRNA gene translocation observed in Polyplax lice was only between different types of minichromosomes and towards the boundaries with the control region. A similar pattern of tRNA gene translocation can also been seen in other sucking lice with fragmented mt genomes.

Conclusions We conclude that inter-minichromosomal tRNA gene translocation orientated towards the boundaries with the control region is a major contributing factor to the highly dynamic mitochondrial genome organization in the parasitic lice of mammals.

VL - 22 UR - https://bmcgenomics.biomedcentral.com/articles/10.1186/s12864-021-07859-w IS - 1 ER - TY - JOUR T1 - Ectoparasitic insects and mites on Yunnan red-backed voles (Eothenomys miletus) from a localized area in southwest China JF - Parasitology Research Y1 - 2013 DO - 10.1007/s00436-013-3537-6 A1 - Guo,Xian-guo A1 - John R. Speakman A1 - Dong,Wen-ge A1 - Xing-yuan Men A1 - Qian,Ti-jun A1 - Dian Wu A1 - Feng Qin A1 - Wen-yu Song SP - 3543 EP - 3549 AB -

Ectoparasitic insects and mites on Yunnan red-backed voles (Eothenomys miletus) in Dali prefecture, Yunnan Province, southwest China, were studied between 2003 and 2004. In total, 34,389 individuals of 86 species of ectoparasitic insects (seven species of fleas and five species of sucking lice) and mites (23 species of gamasid mites and 51 species of chigger mites) were collected from 916 individual hosts. The diversity of ectoparasites on this single rodent species in such a small area was much higher than in previous reports, which concerned more host species and greater geographical areas. The majority of the ectoparasites were chigger mites, which accounted for 59.3 % of the parasite species and 87.4 % of the individual parasites. Most voles harbored parasites with an overall prevalence (P) of 82.5 % and mean abundance (MA) of 37.5 parasites per host. The dispersion coefficient (C) and patchiness index (m*/m) were used to study the spatial patterns of the seven dominant parasite species, and all seven had aggregated distributions. The species abundance distribution of the ectoparasites on the vole was fitted by Preston’s lognormal distribution (R 2 = 0.82), and the total expected parasite species was estimated from this plot as 167 species. Yunnan red-backed voles harbor many ectoparasites as revealed by examination of a large host population. Future field investigations should sample large numbers of host individuals to assess ectoparasite populations.

VL - 112 UR - http://link.springer.com/10.1007/s00436-013-3537-6 IS - 10 JO - Parasitol Res ER - TY - JOUR T1 - Fragmented 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 cycle JF - BMC Genomics Y1 - 2014 DO - 10.1186/1471-2164-15-44 A1 - Dong,Wen-ge A1 - Simon Song A1 - Dao-chao Jin A1 - Guo,Xian-guo A1 - Renfu Shao SP - 44 KW - Chromosome evolution KW - genome fragmentation KW - minichromosome KW - Mitochondrial genome KW - sucking lice AB -

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.

VL - 15 UR - http://bmcgenomics.biomedcentral.com/articles/10.1186/1471-2164-15-44 IS - 44 JO - BMC GenomicsBMC Genomics ER - TY - JOUR T1 - Fragmented mitochondrial genomes are present in both major clades of the blood-sucking lice (suborder Anoplura): evidence from two Hoplopleura rodent lice (family Hoplopleuridae) JF - BMC Genomics Y1 - 2014 DO - 10.1186/1471-2164-15-751 A1 - Dong,Wen-ge A1 - Simon Song A1 - Guo,Xian-guo A1 - Dao-chao Jin A1 - Qianqian Yang A1 - Stephen C. Barker A1 - Renfu Shao SP - 13 pp KW - Chromosome evolution KW - genome fragmentation KW - minichromosome KW - Mitochondrial genome KW - sucking lice AB -

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.

VL - 15 UR - http://bmcgenomics.biomedcentral.com/articles/10.1186/1471-2164-15-751 IS - 751 JO - BMC GenomicsBMC Genomics ER - TY - JOUR T1 - Understanding mitochondrial genome fragmentation in parasitic lice (Insecta: Phthiraptera) JF - Hereditas (Beijing) Y1 - 2013 DO - 10.3724/SP.J.1005.2013.00847 A1 - Dong,Wen-ge A1 - Guo,Xian-guo A1 - Dao-chao Jin A1 - Shi-peng Xue A1 - Simon Song A1 - Stephen C. Barker A1 - Renfu Shao SP - 847 EP - 855 KW - Chromosome evolution KW - genome fragmentation KW - Mitochondrial genome AB -

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.

VL - 35 UR - https://www.researchgate.net/publication/249321853_Understanding_mitochondrial_genome_fragmentation_in_parasitic_lice_Insecta_Phthiraptera IS - 7 ER - TY - JOUR T1 - Study on the fauna and species diversity of sucking lice in China JF - Sichuan Journal of Zoology Y1 - 2009 A1 - Guo,Xian-guo A1 - Yan-fen Meng SP - 147 EP - 152 KW - China KW - fauna KW - host animals KW - species diversity KW - sucking lice KW - zoogeography AB -

Paper written in Chinese

Brief summary: Sucking lice are exclusively hematophagous ectoparasites of eutherian mammals, and are world-wide distribution. The results show that 96 species belonged to 22 genera, 11 families of Anoplura have been described in China, accounting for 64.71 % , 45.83%, 17.14% of known sucking lice secies, general and families in the world, respectively.

There are 27 endemic sucking lice species in China.Each family (genus) of sucking louse has the corresponding host animal and parasites on the specific family (genus) host animal. The results indicate that the fact there is a high host specificity of sucking lice and also represent the ecology phenomenon of coevolutionary relationship between sucking lice and their mammal hosts.

The paper provided a list of names of the host animals and sucking lice in China and a comparison of known genus of the lice in China with the rest of the world.

VL - 28 UR - http://phthiraptera.info/sites/phthiraptera.info/files/94792.pdf IS - 1 ER - TY - JOUR T1 - Species Abundance Distribution of Ectoparasites on Norway Rats (Rattus norvegicus) from a Localized Area in Southwest China JF - Journal of Arthropod-Borne Diseases Y1 - 2016 A1 - Guo,Xian-guo A1 - Dong,Wen-ge A1 - Xing-yuan Men A1 - Qian,Ti-jun A1 - Dian Wu A1 - Tian-guang Ren A1 - Feng Qin A1 - Wen-yu Song A1 - Zhi-hua Yang A1 - Quinn E. Fletcher SP - 192 EP - 200 KW - ectoparasite KW - Expected species estimation KW - Norway rat KW - Species abundance distribution AB -

Background: The species of ectoparasites that live on a specific host in a geographical region form an ectoparasite community. Species abundance distributions describe the number of individuals observed for each different species that is encountered within a community. Based on properties of the species abundance distribution, the expected total number of species present in the community can be estimated.
Methods: Preston’s lognormal distribution model was used to fit the expected species abundance distribution curve. Using the expected species abundance distribution curve, we estimated the total number of expected parasite species present and the amount of species that were likely missed by our sampling in the field.
Results: In total, 8040 ectoparasites (fleas, sucking lice, gamasid mites and chigger mites) were collected from 431 Norway rats (Rattus norvegicus) from a localized area in southwest China. These ectoparasites were identified to be 47 species from 26 genera in 10 families. The majority of ectoparasite species were chigger mites (family Trombicu- lidae) while the majority of individuals were sucking lice in the family Polyplacidae. The expected species abun- dance distribution curve demonstrated the classic pattern that the majority of ectoparasite species were rare and that there were a few common species. The total expected number of ectoparasite species on R. norvegicus was estimated to be 85 species, and 38 species were likely missed by our sampling in the field.
Conclusions: Norway rats harbor a large suite of ectoparasites. Future field investigations should sample large num- bers of host individuals to assess ectoparasite populations.

VL - 10 UR - http://phthiraptera.info/sites/phthiraptera.info/files/94359.pdf IS - 2 ER - TY - JOUR T1 - Spatial Distribution Pattern of Hoplopleura affinis (Anoplura: Hoplopleuridae) on its rat host, Apodemus chevrieri in Yunnan, China JF - Endemic Diseases Bulletin Y1 - 2005 A1 - Guo,Xian-guo A1 - Qian,Ti-jun A1 - Guo,Li-jun A1 - Wang,Jing A1 - Dong,Wen-ge A1 - Zhang,Li A1 - Ma,Zhi-mim A1 - Li,Wei SP - 22 EP - 26 KW - China AB -

Objective To determine the spatial pattern of Hoplopleura affinis among the individuals of its dominant rat host, Apodemus chevrieri and to illustrate how the ectoparasitic sucking louse individuals distribute among their rat host individuals. Methods Iwao's linear regression method and a significance test of random deviation were used to analyze the spatial distribution pattern of Hoplopleura affinis among the individuals of Apodemus chevrieri. Results Hoplopleura affinis is a common sucking louse species on the body surface of Apodemus chevrieri, a common wild rat species in Yunan Province of China. In the light of Iwao's method, the equation for Hoplopleura affinis is M*=3.10 + 6.69M (r=0.67, P<0.05). Both α and β in the equation (α= 3.10, β=6.69) are higher than 0 and 1, the border values for determining spatial pattern of populations. The F values is 8.77(F>F0.05(2,6), P<0.05) in the significance test of random. The spatial pattern of Hoplopleura affinis among the individuals of its dominant host (Apodemus chevrieri) is of aggregated distribution. Conclusions The result suggests that the individuals of Hoplopleura affinis do not evenly distribute among its rat host individuals, but have a tendency to gather together and form different individual louse groups on the body surface of the rat host.

VL - 20 UR - http://en.cnki.com.cn/Article_en/CJFDTotal-DFBT200502012.htm IS - 2 ER -