Population genetics of marmosets in Asian primate research centers and loci associated with epileptic risk revealed by whole-genome sequencing

The common marmoset(Callithrix jacchus)has emerged as a valuable nonhuman primate model in biomedical research with the recent release of high-quality reference genome assemblies.Epileptic marmosets have been independently reported in two Asian primate research centers.Nevertheless,the population genetics within these primate centers and the specific genetic variants associated with epilepsy in marmosets have not yet been elucidated.Here,we characterized the genetic relationships and risk variants for epilepsy in 41 samples from two epileptic marmoset pedigrees using whole-genome sequencing.We identified 14558184 single nucleotide polymorphisms(SNPs)from the 41 samples and found higher chimerism levels in blood samples than in fingernail samples.Genetic analysis showed fourth-degree of relatedness among marmosets at the primate centers.In addition,SNP and copy number variation(CNV)analyses suggested that the WW domain-containing oxidoreductase(WWOX)and Tyrosine-protein phosphatase nonreceptor type 21(PTPN21)genes may be associated with epilepsy in marmosets.Notably,KCTD18-like gene deletion was more common in epileptic marmosets than control marmosets.This study provides valuable population genomic resources for marmosets in two Asian primate centers.Genetic analyses identified a reasonable breeding strategy for genetic diversity maintenance in the two centers,while the case-control study revealed potential risk genes/variants associated with epilepsy in marmosets.

Molecular phylogenetics and population demographic history of Amphioctopus fangsiao,inferred from mitochondrial and microsatellite DNA markers

Amphioctopus fangsiao(Cephalopoda:Octopodidae)is an important commercial species in the coastal waters of China.In recent years,however,the resource of A.fangsiao have declined because of habitat destruction and overfishing.To analyze the genetic variations of A.fangsiao caused by the fluctuation of resources,the population genetic structure of nine sampling locations collected from the Bohai Sea to the South China Sea were investigated,using mtDNA COI fragments and microsatellite DNA.The results of F-statistics,AMOVA,STRUCTURE and PCA analyses showed three phylogeographic clades(Clades A,B and C),revealing limited genetic exchange between north and south populations.These clades diverged in 2.23(Clades A and B)and 3.67(Clades A,B and C)million years ago,during the dramatic environmental fluctuations,such as sea level and temperature changes,have exerted great influence on the survival distribution pattern of global organisms.Our results for low genetic connectivity among A.fangsiao populations provide insights into the development of management strategies,that is,to manage this species as separate management unit.

Population genetics and forensic efficiency of 30 InDel markers in four Chinese ethnic groups residing in Sichuan

Sichuan Province is located at the transitional junction regions of the Qinghai-Tibet Plateau and the low-altitude plains.It also serves as the corridor of Sino Tibetan-speaking population migration and expansion since neolithic expansion of Proto-Tibeto-Burman populations from Middle/Upper Yellow River during Majiayao period(3300-2000 BC).However,the population structure and the corresponding genetic diversity of forensic-related markers in this region remain unclear.Thus,we genotyped 30 insertion-deletion(InDel)markers in 444 samples from four ethnic groups(Han,Tibetan,Hui and Yi)from Sichuan Province using the Investigator■ DIPplex kit to explore the characteristics of population genetics and forensic genetic focuses.All the loci were found to be in Hardy-Weinberg Equlibrium(HWE)after applying a Bonferroni correction and no pairwise loci showed prominent linkage disequilibrium.The combined matching probability(CMP)and the combined power of discrimination(CPD)are larger than 1.8089×10^(11)and 0.9999999995,respectively.Principal component analysis,multi-dimen-sional scaling plots and Neighbour-Joining tree among 65 worldwide populations indicated that Sichuan Hui and Han are genetically close to Hmong-Mien and Tai-Kadai-speaking popula-tions,and Sichuan Tibetan and Yi bear a strong genetic affinity with Tibeto-Burman-speaking populations.The model-based genetic structure further supports the genetic affinity between the studied populations and linguistically close populations.

The Hardy-Weinberg principle and its applications in modern population genetics

The discovery of the Hardy-Weinberg principle marked the beginning of the field of population genetics.Over the past hundred years,it has provided a starting point for many population genetic investigations.In this review,the Hardy-Weinberg principle,its statistical testing,and several of its applications in various modern population genetic research areas,including allelic variability and selection in the human leukocyte antigen region,microsatellite genotyping error detection,and accuracy of haplotype estimation,are discussed.

DISTRIBUTION OF ALPHA-1-ANTITRYPSIN VARIANT ETOKYO AND ITS IMPLICATION IN HUMAN POPULATION GENETICS

Ⅰ. INTRODUCTION Alpha-1-antitrypsin (A1AT; locus symbol, PI) is one of the main protease inhibitors in serum. Up to now there are at least 50 A1AT variants that have been found in human populations (Cox, D. W., private communication). The distribution of A1AT variants appears highly racial specificity and geographical variability. This

Haplotype and Genetic Analysis of 41 Y-STR Loci in the Wuwei Han Population from Gansu Province,China

Objective Y-Chromosomal short tandem repeat polymorphism(Y-STR)analysis plays an indispensable role in the identification of male individuals,population genetics,and biogeographic research.While profiles of many populations based on Y-STR markers in human genomes are ample,haplotype data for the Wuwei Han are still scarce.Methods In this study,2180 unrelated Wuwei Han male individuals residing in Gansu Province,China were collected and genotyped using the novel Microreader™40Y Plus ID system.Phylogenetic relationship reconstructions,multidimensional scaling(MDS),and heatmap analysis were performed based on the genetic distance(Rst)values between our studied population and other populations of the Ymax module in the Y-STR Haplotype Reference Database(YHRD).Results A total of 2129 unique haplotypes were obtained,and the haplotype diversity(HD)and discrimination capacity(DC)for the Wuwei Han were 0.9999 and 0.9931,respectively.Conclusion Our results demonstrate that the Wuwei Han population had intimate genetic relationships with East Asians,especially the geographically close Han populations.Overall,this Y-Chromosomal assay gives valuable information about paternal lineages in male individual tracking and genealogical database construction.

Mitogenomic Conservation Genetics of the Critically Endangered Liaoning Clawed Salamander

The Liaoning clawed salamander(Onychodactylus zhaoermii)is an endemic and critically endangered amphibian species of China.To study the population genetics of natural populations of this species,32 samples were collected from six different locations,and the mitochondrial genome was sequenced.Population genetic analyses showed that the Liaoning clawed salamander is composed of only one radialized cluster with ultralow nucleotide diversity.Late Pleistocene climate cooling(-100 to-30 kya)may have reduced the effective population size of the Liaoning clawed salamander,and the subsequent temperature increase(~25 kya to present)provided the opportunity for population expansion.Because of heat sensitivity,the maximum temperature of the prebreeding period,especially from March to May,is very important for the surface environment living in the Liaoning clawed salamander.Three suitable regions were predicted by the MaxEnt model,and the largest suitable region(approximately 899 km2)was at the four-county boundary area and was larger than the present’Natural Conservation Community of the Liaoning Clawed Salamander’.To ensure more effective protection of all Liaoning clawed salamanders,we suggest extending the current’Natural Conservation Community of the Liaoning Clawed Salamander’to include the four-county boundary area.

Population Genetic Analysis of Sillago nigrofasciata (Perciformes:Sillaginidae) Along the Coast of China by Sequencing Mitochondrial DNA Control Region

Sillago nigrofasciata, a small to moderate size nearshore species, is newly found along the eastern and southern coasts of China. The present study is carried out in order to analyze the population genetics of the S. nigrofasciata. The control region sequence of mitochondrial DNA revealing 73 haplotypes were obtained from 162 individuals collected at 8 locations along the coast of China. The whole S. nigrofasciata population along the coast of China showed a low nucleotide diversity(0.012) and a high population diversity(haplotype diversity)(0.943), and all the 8 local populations showed low nucleotide diversities(0.014 – 0.001), suggesting the protective measures are effective. The haplotypes of the 8 local populations were widely distributed in haplotype network diagram and neighbor-joining phylogenetic tree, while no branch associating with sampling locations was detected. Recent gene flow analysis showed asymmetric gene exchanges among local populations. The pairwise FST values and unweighted pair-group method with arithmetic mean(UPGMA) tree revealed a certain amount of genetic difference among local populations. Moreover, analysis of molecular variance(AMOVA) reflected genetic differences between hypothetical subdivision groups. Neutral test and mismatch distribution of pairwise nucleotide suggested S. nigrofasciata may have experienced recent population expansion events. The historical geographic events associating with ice age may be the main explanation to the heterogeneity among local populations with short geographic distances, and the homogeneity among local populations with long geographic distances.

Reveal the Population Genetic Characteristics of Bombay Duck (Harpadon nehereus) in Coastal Waters of China with Genotyping-by-Sequencing Technique

Bombay duck(Harpadon nehereus)is an economically important species in the estuarine and coastal offshore waters of the Indo-West Pacific.This study aims to reveal the genome-wide genetic characteristics of five populations of H.nehereus from the coastal areas of China by using the genotyping-by-sequencing technique.After strict filtering,32088 high-quality single-nucleotide polymorphism markers were detected and analyzed.The average observed heterozygosity and expected heterozygosity ranged from 0.41651 to 0.56725 and from 0.30998 to 0.45531,respectively,indicating that heterozygosity excess occurred in H.nehereus populations.The nucleotide diversity ranged from 0.63664 to 0.74868,which was larger than those from other marine fishes.No obvious genetic structure was detected among H.nehereus populations,and the genetic variation originated within individuals.Extensive gene exchange caused by longshore currents in the reproductive season might be the primary reason for the weak genetic differentiation.Among various environmental factors,water temperature might be the key element affecting the genetic structure of H.nehereus.Due to the destruction and overfishing of spawning grounds,the fishery resources declined in recent years.This study could serve as a reference for the resource protection and rational utilization of H.nehereus.

Microsatellite marker development and population genetic analysis revealed high connectivity between populations of a periwinkle Littoraria sinensis(Philippi,1847)

Periwinkle Littoraria sinensis is a widely distributed gastropod in rocky intertidal zone of the northwestern Pacifi c.To examine genetic diversity and genetic connectivity among coastal populations of L.sinensis in China,1636 pairs of primers were successfully designed using whole-genome shotgun sequencing,de novo assembly,and a bioinformatics pipeline QDD.Twelve highly variable polymorphic markers were selected to genotype 351 individuals from 15 populations.Data of nine microsatellite loci were retained for population genetic analysis,and weak genetic differentiation among populations were detected,suggesting high gene flow among populations.The long planktonic larval duration of L.sinensis might have played an important role in the high gene flow among populations.A tendency of genetic differentiation between north and south populations of L.sinensis was detected,which might be resulted from isolation due to lowered sea level in the last glacial maximum.Furthermore,the newly founded populations along the coast of Jiangsu Province were closely related to populations to the south of the Changjiang(Yangtze)River estuary,suggesting that the main source of the newly founded populations is from natural rocky populations south of the estuary.

Genetic Differentiation of Japanese Sardinella(Sardinella zunasi) Populations in the Northwest Pacific Revealed by ISSR Analysis

Knowledge of population genetic structure plays an important role in fisheries management.In this research,In-ter-Simple-Sequence-Repeat(ISSR)markers were employed to evaluate the genetic structure of Japanese sardinella(Sardinella zun-asi)populations in the Northwest Pacific.Eighty seven individuals from 5 locations were screened using 4 highly polymorphic prim-ers.A total of 173 polymorphic loci were detected out of 191 loci amplified.Small but significant genetic differentiation was de-tected between the Chinese and Japanese populations by both AMOVA and pairwise FST analyses,which was further supported by cluster analysis.We consider that climate change during glaciations should be responsible for the genetic differentiation.Isolation by geographic distance among populations was observed,indicating that the distance might also lead to the genetic differentiation.However,no genetic structure was found within the populations off both the Chinese and Japanese coasts,indicating a high-level along-coast gene flow,which might result from ocean current transport and common ground for over-wintering.

Salinity Tolerance in Argentinean Population of <i>Bromus catharticus</i>. Variability and Direct and Indirect Effects on Seedling Characters

The aim of this research was to evaluate the salinity tolerance in prairie grass populations at the seedling stage quantifying the variability and the influence of physiological traits related to it. Salinity tolerance, in Bromus catharticus Vahl (prairie grass) populations collected in different environments of the Pampean Phytogeography region (Argentine) was evaluated at the seedling stage, using controlled condition of temperature and light. It was adopted a completely randomized design using 3 plots with three plants each one per population and two levels of treatment: 0 mM and 100 mM NaCl. Morphological, biomass and membrane stability root and shoot traits were studied. A factorial ANOVA with interaction was estimated. Then one way ANOVA for all seedling traits in both treatments allowed estimating variance components, coefficient of genotypic determination (CGD) and variation index (VI). Comparisons between populations were made using Tukey test (at 5% of probability). Phenotypic correlations among traits were calculated and then a path coefficient analysis separated direct and indirect effects at 100 and 0 mM NaCl. No significant interactions “Population × Treatment” were found for any character. The saline stress caused a pairing in the population means for the most traits. Coefficients of variation were mainly higher when the seedlings grew without stress (0 mM) because it allowed a greater potential genotypic expression. The absence of significant interactions denotes a good homeostatic capacity of the prairie grass facing that abiotic stress. Leaf length, shoot length and root dry matter were the variables with the largest direct and indirect effects. Our results showed an increase for them at salt and demonstrated intraspecific variation, possibly in relation with the origin sites. Plants under stress showed a marked resilience, in order to quickly restore the same biomass allocation patterns that occur in non-stress environment.

DNA Barcoding,Fungal Diversity,and Authentication of Wild Gourmet Mushrooms

The application of molecular tools for the identification of strains,populations and species has become a common practice in a variety of applied and basic investigations in many parts of the world.However,standardization of such applications varies widely among organisms and scientific fields.In this mini-review,the author provides a brief introduction to one of the most prominent effort for species identification-the international barcode of life(iBOL) project,discusses the features of fungal diversity including the proposed fungal barcode DNA fragment-the intergenic spacer regions(ITS) of the nuclear ribosomal RNA gene clusters,and illustrates the potential promises and problems of using ITS for barcoding and for analyzing the phylogeographic pattern of the wild gourmet mushroom Tricholoma matsutake species complex.The analyses show that identification to species level is often insufficient for practical applications and that sequences from multiple genes in combination with critical morphological and physiological evaluations are needed to identify strains,populations and species.

Neosporosis: An Overview of Its Molecular Epidemiology and Pathogenesis

Neospora caninum (N. caninum), a cyst-forming protozoan parasite, is a major cause of bovine abortions and neonatal mortality worldwide. N. caninum has a broad intermediate host range, and its sexual cycle occurs exclusively in canids. Another species of Neospora, Neospora hughesi (N. hughesi), has been identified and causes myeloencephalitis in horses. Although molecular epidemiology studies are in their infancy, the 18S ribosomal RNA (rRNA) and ITS1 regions within the small subunit ribosomal RNA (ssuRNA) and an N. caninum species-specific DNA probe (pNc5) have been used extensively to differentiate Neospora from other closely related apicomplexan parasites. While these repetitive regions have higher sensitivity and specificity than housekeeping or antigen genes, they suffer from low discriminatory power and fail to capture intra-species diversity. Similarly, although multiple minisatellite or microsatellite marker studies have shown clear geographic substructures within Neospora, strains are often misclassified due to a convergence in the size of different alleles at microsatellite loci, known as homoplasy. Only one strain, N. caninum Liverpool (Nc-Liv), has been genome sequenced and compared with its closest relative, Toxoplasma gondii (T. gondii). Hence, detailed population genomics studies based on whole-genome sequences from multiple strains worldwide are needed in order to better understand the current population genetic structure of Neospora, and ultimately to determine more effective vaccine candidates against bovine neosporosis. The aim of this review is to outline our current understanding of the molecular epidemiology and genomics of Neospora in juxtaposition with the closely related apicomplexan parasites Hammondia hammondi and T. gondii.

Population isolation shapes plant genetics, phenotype and germination in naturally patchy ecosystems

Aims Habitat connectivity is important in conservation since isolation can diminish the potential of a population for adaptation and increase its risk of extinction.However,conservation of naturally patchy ecosystems such as peatlands has mainly focused on preserving specific sites with exceptional characteristics,neglecting the poten-tial interconnectivity between patches.In order to better under-stand plant dynamics within a peatland network,we assessed the effect of population isolation on genetic distinctiveness,phenotypic variations and germination rates using the peatland-obligate white-fringed orchid(Platanthera blephariglottis).Methods Fifteen phenotypic traits were measured for 24 individuals per pop-ulation(20 distinct populations,Quebec,Canada)and germination rates of nearly 20000 seeds were assessed.Genetic distinctiveness was quantified for 26 populations using single nucleotide polymor-phism markers obtained via a pooled genotyping-by-sequencing approach.Geographic isolation was measured as the distance to the nearest population and as the number of populations occurring in concentric buffer zones(within a radius of 2,5 and 10 km)around the studied populations.Important Findings All phenotypic traits showed significant differences among popu-lations.Genetic results also indicated a pattern of isolation-by-distance,which suggests that seed and/or pollen exchange is restricted geographically.Finally,all phenotypic traits,as well as a reduced germination rate,were correlated with either geographic isolation or genetic distance.We conclude that geographic iso-lation likely restricts gene flow,which in turn may affect germi-nation.Consequently,it is imperative that conservation programs take into account the patchy nature of such ecosystems,rather than targeting a few specific sites with exceptional character for preservation.

Assessment of Genetic Diversity of NIFOR Oil Palm Main Breeding Parent Genotypes Using Microsatellite Markers

The genetic diversity among 15 NIFOR breeding parents was assessed using 10 microsatellite markers. A high genetic diversity was observed with a total of 64 alleles including 23 rare alleles or alleles at frequencies less than 0.05. The NIFOR tenera parents recorded the highest number of rare alleles. The average observed heterozygosity and mean gene diversity across all parental groups were 0.6889 and 0.7029, respectively. Higher genetic diversity was detected among the NIFOR dura and tenera parents compared to that of the Deli dura parents in absolute terms. Analysis of molecular variance (AMOVA) showed that 87% of the total variation (p < 0.001) observed was due to differences among parents. Rogers’ genetic distance ranged from 0.2988 to 0.8000 (mean = 0.5570). The dendrogram constructed on the basis of Rogers’ genetic distance clustered the parents in three groups. They generally clustered in heterotic manner rather than by geographic origins. The groupings obtained through PCoA confirmed the results obtained by cluster analysis. The results obtained are strong assets for NIFOR breeding programme.

High regional genetic differentiation of an endangered relict plant Craigia yunnanensis and implications for its conservation

Of the genus Craigia,widespread in the Tertiary,only two relict species survived to modern times.One species is now possibly extinct and the other one,Craigia yunnanensis,is severely endangered.Extensive surveys have located six C.yunnanensis populations in Yunnan province,southwest China.Using fluorescent amplified fragment length polymorphism(AFLP),the genetic diversity and population structure of these populations were examined.It was found that genetic diversity of C.yunnanensis was moderate at the species level,but low at regional and population levels.Analysis of population structure showed significant genetic differentiation between Wenshan and Dehong regions,apparently representing two geographically isolated for long time refuges.There are also clear indications of isolation between populations,which,together with anthropogenically caused decline of population size,will lead to general loss of the species genetic variation with subsequent loss of adaptive potential.To conserve the genetic integrity of C.yunnanensis,we recommend that ex-situ conservation should include representative samples from every population of the two differentiated regions(e.g.Wenshan and Dehong).The crosses between individuals originated from different regions should be avoided because of a high risk of outbreeding depression.As all the extant populations of C.yunnanensis are in unprotected areas with strong anthropogenic impact,there is no alternative to reintroduction of C.yunnanensis into suitable protected locations.

MutL homolog 1 methylation and microsatellite instability in sporadic colorectal tumors among Filipinos

BACKGROUND Colorectal cancer(CRC)ranks third in terms of incidence and second in mortality worldwide.In CRC,the silencing of mismatch repair genes,including the mutL homolog 1(hMLH1)has been linked to microsatellite instability(MSI),the lengthening or shortening of microsatellite repeats.Very limited data have been presented so far on the link of hMLH1 methylation and MSI in Southeast Asia populations with sporadic CRC,and on its clinical significance.AIM To investigate the significance of the MSI status and hMLH1 methylation in CRC Filipino patients.METHODS Fifty-four sporadic CRC patients with complete clinical data were included in this study.Genomic DNA from CRC tumor biopsies and their normal tissue counterparts were profiled for MSI by high resolution melting(HRM)analysis using the Bethesda Panel of Markers(BAT25,BAT26,D2S123,D5S346,and D17S250).hMLH1 methylation screening was performed using bisulfite conversion and methylation specific polymerase chain reaction.Statistical analysis was conducted to calculate their associations to clinicopathological characteristics and survival relevance(Kaplan-Meier curves and the log-rank test).RESULTS hMLH1 methylation was observed in 9%and 35%of CRC and normal samples,respectively.Higher incidence of consistently methylated hMLH1 found in both normal and CRC was noticed for relation to location of tumor(P<0.05).As for MSI status,D2S123 the most common unstable microsatellite and MSI-high(MSIH)was the most common MSI profile,counted for 46%and 50%of normal and CRC tissues,respectively.The presence of MSI-low(MSI-L)and microsatellite stable(MSS)was 43%and 11%for normal,and 31%and 19%for CRC samples.The mean month of patients’survival was shorter in patients whose normal and tumor tissues had methylated compared to those with unmethylated hMLH1 and with MSI-H compared to those with MSI-L/MSS(P<0.05).This was supported by significant difference in Kaplan-Meier with log-rank analysis.This data indicated that hMLH1 methylation and high MSI status have prognostic value.CONCLUSION This study showed the clinical significance of hMLH1 methylation and MSI status in sporadic CRC Filipino patients,especially in the normal part of the tumor.

Phylogeny,genetics,and the partial life cycle of Oncomegas wageneri in the Gulf of Mexico

Despite the diversity and ecological importance of cestodes,there is a paucity of studies on their life stages(i.e.,complete lists of intermediate,paratenic,and definitive hosts)and genetic variation.For example,in the Gulf of Mexico(GoM)98 species of cestodes have been reported to date;however,data on their intraspecific genetic variation and population genetic studies are lacking.The trypanorhynch cestode,Oncomegas wageneri,is found(among other places)off the American Western Atlantic Coast,including the GoM,and has been reported as an adult from stingrays and from several teleost species in its larval form(as plerocerci).This study represents the first report of 2 previously unregistered definitive hosts for O.wageneri,namely the Atlantic sharpnose shark Rhizoprionodon terraenovae and the southern stingray Hypanus americanus.In this work,partial sequences of the 28S(region D1-D2)ribosomal DNA were analyzed to include O.wageneri within an eutetrarhynchoid phylogenetic framework.All O.wageneri individuals(which included plerocerci and adults)were recovered as monophyletic and Oncomegas celatus was identified as the sister species of O.wageneri.Furthermore,population genetic analyses of O.wageneri from the southern GoM were carried out using DNA sequences of the mitochondrial cytochrome c oxi-dase subunit 1(COI)gene,which reflected high genetic variation and a lack of genetic structure among the 9 oceanographic sampling sites.Based on these results,O.wageneri is panmictic in the southern GoM.More extensive sampling along the species entire distribution is necessary to make more accurate inferences of population genetics of O.wageneri.

An interpretation of the genetic polymorphism and population genetic background of Ankang Han population via a novel InDel panel

In this research,genotyping data of 43 InDel loci in 311 Han individuals in Ankang City,Shaanxi Province,China were detected using a self-developed five-dye multiplex amplification panel.The allelic frequencies and forensic parameters of all InDel loci were calculated.The combined power of discrimination and probability of exclusion values were 0.99999999999999999882739 and 0.999887424,respectively,which demonstrated that this 43-InDel panel was powerful for individual identifications in Ankang Han population.Moreover,genetic distances,pairwise F_(ST)values,principal component analyses,phylogenetic trees and STRUCTURE analyses were performed to investigate the genetic affinities between Ankang Han and reference groups.Population genetic investigations indicated that Ankang Han population had a close genetic relationship with Southern Han population compared with other reference groups.