Genetic structure of Pallas’s squirrel (Callosciurus erythraeus) populations from artificial forests in Hongya County, Sichuan, China

To understand levels of population differentiation in Pallas’s squirrel (Callosciurus erythraeus) in fragmented habitats, we collected 83 samples from three patches of artificial forest in Hongya County, Sichuan Province, China. Sample numbers from each patch were as follows: 16 from Hanwang (HW), 27 from Muchansi (MCS) and 40 from Yanyandong (YYD). The mitochondrial DNA control region was sequenced and 18 haplotypes were observed. Our results showed that haplotype diversities of the three C. erythraeus populations were similar (0.771, 0.791 and 0.733). Fixation indices (F_st) of pairwise populations were between 0.21 and 0.31, and the estimated gene flow (Nm) was between 1 and 2. Analysis of molecular variance (AMOVA) showed that most molecular variation occurred within populations (74.82%); variances among populations were small but there was significant genetic differentiation. In addition, the neighbour-joining (NJ) tree showed three clades in the phylogenetic tree for population genetic structure. This was confirmed by the median-joining haplotype network. Furthermore, analysis of isolation by distance (IBD) showed that genetic differentiation among the three populations was positively related to geographical distance. However, tests of neutrality and the observed mismatch distribution of pairwise differences between sequences indicated that C. erythraeus populations were relatively stable in the past.     

Genetic variation and structure in natural and reintroduced populations of the endangered legume,Pyne’s ground plum (Astragalus bibullatus)

Conservation Genetics - Rare species with limited geographic distributions and small census populations are particularly susceptible to genetic drift and inbreeding. Assessing genetic variation...     

Three new Species of Tabanidae from Sichuan,China (Diptera)

This report discribes 2 new species of Haematopota, 1 new species of Tabanus and 2 males of T. omeishanensis Xu, and T. liangshanensis Xu. All the types are deposited in the Institute of Microbiology & Epidemiology, Academy of Military Medical Sciences, P.L.A., China. Haematopota erlangshanensis, sp. nov. (fig. 1; 2—2) This species is related to H. hakusanensis Togashi, but is easily     

Two new Species of Lasiohelea from Sichuan,China(Diptera,Ceratopogonidae)

1. Lasiohelea aeschrodenta, sp. nov Female Head with eyes bare, AR 2.09;maxillary palp with a sensory pore on segment 3. Buccal armature has about 10 teeth which separated irregulary in the cibarium;clypeus with about 16 setae. Wing about 0.86 mm. long, with bare areas along veins. TR 1.74 in hind leg, with narrow scales on each tarsus. Spermatheca round and small, with abroad basical pore. Holotype:♀ Dukou, Sichuan, 1979 X. 10-11; Paratypes: 2♀♀Sichuan,Xichang, 1979 X. 5.     

Spatio-temporal changes in biomass carbon sinks in China’s forests from 1977 to 2008

Forests play a leading role in regional and global carbon (C) cycles. Detailed assessment of the temporal and spatial changes in C sinks/sources of China’s forests is critical to the estimation of the national C budget and can help to constitute sustainable forest management policies for climate change. In this study, we explored the spatio-temporal changes in forest biomass C stocks in China between 1977 and 2008, using six periods of the national forest inventory data. According to the definition of the forest inventory, China’s forest was categorized into three groups: forest stand, economic forest, and bamboo forest. We estimated forest biomass C stocks for each inventory period by using continuous biomass expansion factor (BEF) method for forest stands, and the mean biomass density method for economic and bamboo forests. As a result, China’s forests have accumulated biomass C (i.e., biomass C sink) of 1896 Tg (1 Tg=10¹² g) during the study period, with 1710, 108 and 78 Tg C in forest stands, and economic and bamboo forests, respectively. Annual forest biomass C sink was 70.2 Tg C a^?1, offsetting 7.8% of the contemporary fossil CO₂ emissions in the country. The results also showed that planted forests have functioned as a persistent C sink, sequestrating 818 Tg C and accounting for 47.8% of total C sink in forest stands, and that the old-, mid- and young-aged forests have sequestrated 930, 391 and 388 Tg C from 1977 to 2008. Our results suggest that China’s forests have a big potential as biomass C sink in the future because of its large area of planted forests with young-aged growth and low C density.     

Genetic structure of Brandt’s vole (<Emphasis Type="Italic">Lasiopodomys brandtii</Emphasis>) populations in Inner Mongolia,China, based on microsatellite analysis

Brandt’s vole (Lasiopodomys brandtii) distribution is discontinuous in Inner Mongolia with some populations isolated from others. Recently, some isolated populations have suffered extinction, and the factors responsible remain elusive. Genetic drift is one of the processes affecting population genetic differentiation, and can play a substantial role in the divergence of small, isolated populations. Using seven microsatellite markers, we genotyped four geographically isolated populations of Brandt’s vole, all of which exhibit episodic fluctuations in population density. The results showed a strong genetic differentiation among the geographically distinct populations (total F _ST = 0.124) and in particular, one population (Zhengxiangbaiqi) was isolated from all others (F _ST values were greatest between Zhengxiangbaiqi and other populations). Furthermore, high levels of inbreeding (F _IS values ranged from 0.205 to 0.290) within each distinct population suggest that inbreeding has and is likely occurring in Brandt’s vole populations. These processes can decrease average individual fitness and consequently increase the risk of extinction of the species.     

Genetic Structure of Przewalski’s Rock Partridge (Alectoris magna) Populations in the Longzhong Loess Plateau, China

In this paper, we have analyzed the nuclear DNA of Alectoris magna samples, collected from the Longzhong Loess Plateau. We used allelic variation at eight microsatellite markers to describe the genetic structure of A. magna populations. The primary goal of this study was to examine the population genetic structure and determine the extent of population differentiation among populations of A. magna. The average value of H _E (0.455) was smaller than H _O (0.477), and there was a heterozygote deficit at the MCW135 locus in the Lanzhou population and the Beidao population. The AB063167 locus in each population (except that of Jingyuan) was not in equilibrium (P < 0.05). The Lixian edge population had a lower proportion of genetic diversity than the central geographic populations; the Haiyuan and Jingyuan populations had higher genetic diversity than the central geographic populations. Analysis of population structure revealed clear differentiation among the eight populations of A. magna, suggesting strong isolation of these populations and correspondingly low levels of migration or gene flow. The A. magna populations of Longzhong Loess Plateau are separated into eastern and western populations by a clustering chart. Genetic data indeed suggest that patterns of speciation and population diversification of A. magna in the Longzhong Plateau have been affected by the stability of the climate, natural selection, and human intervention.     

Prevalence of Kaposi’s sarcoma-associated herpesvirus in Uygur and Han populations from the Urumqi and Kashgar regions of Xinjiang,China

Kaposi’s sarcoma-associated herpesvirus (KSHV) is the infectious etiologic agent associated with Kaposi’s sarcoma (KS), primary effusion lymphoma, and multicentric Castleman disease. It has been shown that high KSHV prevalence and high incidence of both classic KS and AIDSassociated KS are found mostly among people of Uygur ethnicity in Xinjiang, while people of Han ethnicity in Xinjiang have a higher KSHV seroprevalence than those of other Han populations in mainland China. However, it is still unclear why there is such geographical and population variation in KSHV distribution in China. In this work, we focused on the populations in the Kashgar region and Urumqi area, where a total of 1294 research subjects were randomly selected to investigate the potential correlation between KSHV prevalence and different ethnicities in endemic areas of Xinjiang, and to determine risk factors that may affect KSHV infection rates or KS incidence. We identified a high seroprevalence of KSHV and high peripheral blood DNA infection in the general Uygur and Han populations in both Urumqi and Kashgar regions of Xinjiang, and determined that advancing age, low education level, and stationary population status affect KSHV infection rates. Further, KSHV-positive Uygur participants were shown to have higher prevalence of neutralizing antibodies and neutralizing antibody titers than KSHV-positive Han participants.

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Fine-scale genetic structure in populations of the Chagas’ disease vector Triatoma infestans (Hemiptera, Reduvidae)

Fine scale patterns of genetic structure and dispersal in Triatoma infestans populations from Argentina was analysed. A total of 314 insects from 22 domestic and peridomestic sites from the locality of San Martín (Capayán department, Catamarca province) were typed for 10 polymorphic microsatellite loci. The results confirm subdivision of T. infestans populations with restricted dispersal among sampling sites and suggest inbreeding and/or stratification within the different domestic and peridomestic structures. Spatial correlation analysis showed that the scale of structuring is approximately of 400 m, indicating that active dispersal would occur within this distance range. It was detected difference in scale of structuring among sexes, with females dispersing over greater distances than males. This study suggests that insecticide treatment and surveillance should be extended within a radius of 400 m around the infested area, which would help to reduce the probability of reinfestation by covering an area of active dispersal. The inferences made from fine-scale spatial genetic structure analyses of T. infestans populations has demonstrated to be important for community-wide control programs, providing a complementary approach to help improve vector control strategies.     

Latitudinal and elevational patterns of phylogenetic structure in forest communities in China’s mountains

Science China Life Sciences - The phylogenetic structure incorporates both ecological and evolutionary processes to explain assembly of a local community. The “phylogenetic niche...     

Genetic diversity and population structure of North America’s rarest heron, the reddish egret (Egretta rufescens)

The global distribution of the reddish egret is characterized by disjunct colonies occurring from the Pacific side of Northwest Mexico to the Caribbean. We examined distantly isolated colonies of reddish egret to determine global population genetic structure. We used seven polymorphic microsatellites to accomplish five goals: (1) to assess range wide population differentiation among reddish egret (Egretta rufescens) populations, (2) identify extent of gene flow, (3) determine any historical occurrence of bottlenecks, (4) assess genetic differentiation between color morphs, (5) clarify subspecies status of E. r. dickeyi, a completely dark morph population located in and around the Baja California peninsula, Mexico. Genetic differentiation was dramatic (global Fst = 0.161) throughout the reddish egrets range extending from Baja California, Mexico to Great Inagua, Bahamas. Differentiation occurred among three distinct regions (Fst = 0.238) but not among colonies/islands within regions suggesting regional philopatry. Genetic diversity (alleles per locus, and heterozygosity) in Baja California Sur, Mexico and Great Inagua, Bahamas populations is lower than in the Texas/Mexico population due to minimal dispersal between regions and smaller population sizes. Dark and white color morphs when present within the same region showed no differentiation. Patterns of recent population bottlenecks are not evident in each of the three regional populations. With evidence of limited gene flow in addition to low genetic diversity and prospects of habitat loss we recommend that reddish egrets be managed as three distinct or evolutionary significant units.     

Genetic structure of the populations migrating from San Luis Potosi and Zacatecas to Nuevo León in Mexico

The Mexicans residing in the Monterrey metropolitan area in Nuevo León, Mexico, were grouped by generation and birthplace [Monterrey Metropolitan Area (MMA), San Luis Potosi (SLP), and Zacatecas (ZAC)] of the four grandparents to determine the extent of genetic variation within this population and the genetic differences, if any, between the natives living in the MMA and the immigrant populations from SLP and ZAC. Nine genetic marker systems were analyzed. The genetic distance analysis indicates that SLP and ZAC are similar to the MMA, irrespective of birthplace and generation. Gene diversity analysis (GST) suggests that more than 96% of the total gene diversity (HT) can be attributed to individual variation within the population. The genetic admixture analysis suggests that the Mexicans of the MMA, SLP, and ZAC, stratified by birthplace and generation, have received a predominantly Spanish contribution (78.5%), followed by a Mexican Indian contribution (21.5%). Similarly, admixture analysis, conducted on the population of Nuevo León and stratified by generation, indicates a substantial contribution from the MMA (64.6%), followed by ZAC (22.1%) and SLP (13.3%). Finally, we demonstrate that there is no nonrandom association of alleles among the genetic marker systems (i.e., no evidence of gametic disequilibrium) despite the Mestizo origin of this population.     

Three new species of Lathrobium Gravenhorst (Coleoptera, Staphylinidae, Paederinae) from Sichuan, Southwest China

Three new species of the genus Lathrobium Gravenhorst, 1802 from Sichuan Province, Southwest China are described and illustrated: Lathrobium acutissimumsp. n., Lathrobium hailuogouensesp. n. and Lathrobium labahensesp. n. A checklist of Chinese Lathrobium is provided.     

Analysis of clusterin gene (CLU/APOJ) polymorphism in Alzheimer’s disease patients and in normal cohorts from Russian populations

Mutations in three genes PSEN1, PSEN2, and APP are known to be a cause of familial forms of Alzheimer’s disease (AD). APOE gene polymorphism is a strong risk genetic factor for AD. We have evaluated allele and genotype frequency distribution of rs11136000 polymorphism in the clusterin (CLU) gene (or apolipoprotein J, APOJ) in the samples from three Russian populations and in AD patients. Genome-wide association studies in samples from several European populations have recently revealed the highly significant association of CLU gene with AD (p = 8.5 × 10^?10). We found no differences in allele and genotype frequencies of rs11136000 between the populations from the Moscow, Ural, and Siberia regions. The allele frequencies are close to those in European populations. The genetic association analysis in cohort of AD patients and normal individuals (>500 individuals in each group) revealed no significant association of the rs11136000 polymorphism in CLU gene with Alzheimer’s disease in Russian populations. Although our results showed that the CLU gene polymorphism rs11136000 is likely not a major genetic factor for the common form of Alzheimer’s disease, the data do not rule out the possibility of a modest effect of CLU and interaction between CLU and APOE genotypes in etiology of Alzheimer’s disease.     

Molecular Epidemiology of Porcine Cytomegalovirus (PCMV) in Sichuan Province,China: 2010–2012

Porcine cytomegalovirus (PCMV) is an immunosuppressive virus that mainly inhibits the immune function of the macrophage and T-cell lymphatic systems, and has caused huge economic losses to the porcine breeding industry. Molecular epidemiological investigation of PCMV is important for prevention and treatment, and this study is the first such investigation in Sichuan Province, Southwest China. A PCMV positive infection rate of 84.4% (865/1025) confirmed that PCMV is widely distributed in Sichuan Province. A phylogenetic tree was constructed based on the PCMV glycoprotein B gene (gB) nucleotide and amino acid sequences from 24 novel Sichuan isolates and 18 other PCMV gB sequences from Genbank. PCMV does not appear to have evolved into different serotypes, and two distinct sequence groups were identified (A and B). However, whether PCMV from this region has evolved into different genotypes requires further research. Analysis of the amino acid sequences confirmed the conservation of gB, but amino acid substitutions in the major epitope region have caused antigenic drift, which may have altered the immunogenicity of PCMV.     

ISSR Analysis of the Genetic Diversity of the Endangered Species Sinopodophyllum hexandrum （Royle） Ying from Western Sichuan Province, China

Slnopodophyllum hexandrum （Royle） Ying Is an Important medicinal and endangered species. Inter-simple sequence repeats （ISSR） analysis was conducted on seven natural populations from western Slchuan Province to Investigate the genetic diversity of S. hexandrum. Leaf samples of 140 Individuals were collected. Of the 139 discernible fragments generated by 12 selected primers （among 100 primers）, 54 appeared to be polymorphlc. The percentage of polymorphlc bands （PPB） was 38.85% at the species level, and PPB within a population ranged from 7.91% to 23.74%. Low levels of genetic variation （He = 0.092, Ho = 0.142） and high levels of genetic differentiation among the populations （Gst= 62.25%） was detected on the basis of results from POPGENE and analysis of molecular variance （AMOVA）, respectively. Furthermore, the limited gene flow （Nm = 0.361） may result from biological characteristics, such as self-pollination and short distance seed dispersal. Based on the genetic and ecological Information available for S. hexandrum, we propose some appropriate strategies for the conservation of the endangered medicinal species in this region, namely rescuing and conserving the core populations for in situ conservation and sampling and preserving more populations with fewer Individuals from each population for ex situ conservation.     

Microhabitat and plant structure of Compsopogon coeruleus (Compsopogonaceae,Rhodophyta) populations in streams from São Paulo State,southeastern Brazil

Microhabitat distribution was investigated in three populations of C. coeruleus to determine the distributional patterns and their controlling factors, as well as morphometric adaptations to varying conditions on a scale of a few centimetres. Morphometric variations and their relations with physical variables (current velocity, irradiance, depth and type of substratum) revealed some particular characteristics for each population and indicate particular adaptations. However, some trends were clear: 1) larger plants (length and/or diameter) produced a higher quantity of monosporangia in the three populations; 2) plant length and diameter were positively correlated in two populations; 3) plant diameter was positively correlated with current velocity in two populations; 4) higher percent cover was associated with substrata composed of macrophytes in two populations. C. coeruleus occurred under relatively wide microhabitat conditions and had high niche width values, suggesting a tolerance to considerable variation in physical variables. These characteristics contribute to the species' wide distribution in Brazilian streams, both spatial (at distinct scales) and seasonal.     

Genetic mapping of the Lablab purpureus genome suggests the presence of ’cuckoo’ gene(s) in this species

A linkage map of Lablab purpureus consisting of 127 RFLP and 91 RAPD loci was constructed in an F₂ population of 119 individuals. This population was derived from a cross between ’Rongai’ (an annual cultivar) and CPI 24973 (a perennial wild accession). The map comprises 17 linkage groups and covers 1610 centiMorgans (cM) with an average distance of 7 cM between markers. Severe segregation distortions were observed, with the very extreme situation where no paternal type was recovered from the mapping population. These results strongly suggest the presence of a gene conferring preferential transmission from the maternal parent ’Rongai’. It was also clear that, while the majority of RAPD markers are valuable when used together with RFLP or other stringent marker systems, they could be problematic when used solely in mapping exercises. Received: 20 April 1999 / Accepted: 23 August 1999