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Genome-wide association studies (GWAS) have reproducibly associated the single nucleotide polymorphism (SNP) rs12454712 with waist-to-hip ratio adjusted for BMI (WHRadjBMI), but the functional role underlying this intronic variant is unknown. Integrative genomic and epigenomic analyses supported rs12454712 as a functional independent variant. We further demonstrated that rs12454712 acted as an allele-specific enhancer regulating expression of its located gene BCL2 by using dual-luciferase reporter assays and clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9. Specifically, the rs12454712-C allele can bind transcription factor ZNF329, which efficiently elevates the enhancer activity and increases BCL2 expression. Knocking down Bcl2 in 3T3-L1 cells led to the downregulation of adipogenic differentiation marker genes and increased cell apoptosis. A significant negative correlation between BCL2 expression in subcutaneous adipose tissues and obesity was observed. Our findings illustrate the molecular mechanisms behind the intronic SNP rs12454712 for central obesity, which would be a potential and promising target for developing appropriate therapies.

Graphical abstract, Detecting SNPs associated with drug efficacy or toxicity is helpful to facilitate personalized medicine. Previous studies usually find SNPs associated with clinical outcome only in patients received a specific treatment. However, without information from patients without drug treatment, it is possible that the detected SNPs are associated with patients’ clinical outcome even without drug treatment. Here we aimed to detect drug response SNPs based on data from patients with and without drug treatment through combing the cox proportional-hazards model and pairwise Kaplan-Meier survival analysis. A pipeline named Detection of Drug Response SNPs (DDRS) was built and applied to TCGA breast cancer data including 363 patients with doxorubicin treatment and 321 patients without any drug treatment. We identified 548 doxorubicin associated SNPs. Drug response score derived from these SNPs were associated with drug-resistant level (indicated by IC50) of breast cancer cell lines. Enrichment analyses showed that these SNPs were enriched in active epigenetic regulation markers (e.g., H3K27ac). Compared with random genes, the cis-eQTL genes of these SNPs had a shorter protein–protein interaction distance to doxorubicin associated genes. In addition, linear discriminant analysis showed that the eQTL gene expression levels could be used to predict clinical outcome for patients with doxorubicin treatment (AUC = 0.738). Specifically, we identified rs2817101 as a drug response SNP for doxorubicin treatment. Higher expression level of its cis-eQTL gene GSTA1 is associated with poorer survival. This approach can also be applied to identify new drug associated SNPs in other cancers.

Osteoporosis is an age-related complex disease clinically diagnosed with bone mineral density (BMD). Although several genomewide association studies (GWASs) have discovered multiple noncoding genetic variants at 11p15 influencing osteoporosis risk, the functional mechanisms of these variants remain unknown. Through integrating bioinformatics and functional experiments, a potential functional single-nucleotide polymorphism (SNP; rs1440702) located in an enhancer element was identified and the A allele of rs1440702 acted as an allelic specificities enhancer to increase its distal target gene SOX6 (~600 Kb upstream) expression, which plays a key role in bone formation. We also validated this long-range regulation via conducting chromosome conformation capture (3C) assay. Furthermore, we demonstrated that SNP rs1440702 with a risk allele (rs1440702-A) could increase the activity of the enhancer element by altering the binding affinity of the transcription factor TCF4, resulting in the upregulation expression of SOX6 gene. Collectively, our integrated analyses revealed how the noncoding genetic variants (rs1440702) affect osteoporosis predisposition via long-range gene regulatory mechanisms and identified its target gene SOX6 for downstream biomarker and drug development. © 2022 American Society for Bone and Mineral Research (ASBMR).

Ovarian cancer, cervical cancer and endometrial cancer are three relatively common malignant cancers of the female reproductive system. Despite improvements in female genital tract cancer detection and development of new therapeutic approaches, there are still poor prognoses and some do not respond to therapeutic patterns, displaying low survival and high frequency of recurrence. In an era of personalized medicine, novel therapeutic approaches with greater efficacy for these cancers represent an unmet need. One of the actionable signaling pathways is the fibroblast growth factor receptor (FGFR) signaling pathway. Several mutations and alterations in FGF/FGFR family members have been reported in human cancers. FGF/FGFR signaling pathway has become a new target for cancer therapy. This review will summarize the role of FGFR pathway and the genetic alterations of the FGF/FGFR related to female reproductive system cancer. We will describe the available inhibitors of FGFR pathway for potential treatment of female reproductive system cancer. Furthermore, we will discuss FGFR-targeted therapies under clinical development for treatment of female reproductive system cancer.

Graphical abstract, Although genome-wide association studies (GWASs) have successfully identified thousands of risk variants for human complex diseases, understanding the biological function and molecular mechanisms of the associated SNPs involved in complex diseases is challenging. Here we developed a framework named integrative multi-omics network-based approach (IMNA), aiming to identify potential key genes in regulatory networks by integrating molecular interactions across multiple biological scales, including GWAS signals, gene expression-based signatures, chromatin interactions and protein interactions from the network topology. We applied this approach to breast cancer, and prioritized key genes involved in regulatory networks. We also developed an abnormal gene expression score (AGES) signature based on the gene expression deviation of the top 20 rank-ordered genes in breast cancer. The AGES values are associated with genetic variants, tumor properties and patient survival outcomes. Among the top 20 genes, RNASEH2A was identified as a new candidate gene for breast cancer. Thus, our integrative network-based approach provides a genetic-driven framework to unveil tissue-specific interactions from multiple biological scales and reveal potential key regulatory genes for breast cancer. This approach can also be applied in other complex diseases such as ovarian cancer to unravel underlying mechanisms and help for developing therapeutic targets.

Although >80 psoriasis genetic risk loci have been reported through genome-wide association studies (GWASs), the genetic mechanism of psoriasis remains unclear. To identify novel candidate genes associated with psoriasis and reveal the potential effects of genetic factors in the development of psoriasis, we conducted a transcriptome-wide association study (TWAS) based on summary statistics from GWAS of psoriasis (5175 cases and 447 089 controls) and gene expression levels from six tissues datasets (blood and skin). We identified 11 conditionally independent genes for psoriasis after Bonferroni corrections, such as the most significant genes UBLCP1 (PYFS = 2.98 × 10−16) and LCE3C (PSNSE = 9.72 × 10−12, PSSE = 6.24 × 10−12). The omnibus test identified additional five genes associated with psoriasis via the joint association model from multiple reference tissues. Among the 16 identified genes, 5 genes (CTSW, E1F1AD, KLRC3, FIBP and EFEMP2) were regarded as novel genes for psoriasis. We evaluated the 16 candidate genes by querying public databases and identified 11 differentially expressed genes and 8 genes proved by the knockout mice models. Through GO enrichment analyses, we found that TWAS genes were enriched in the known GO terms associated with skin development, such as cornified envelope (P = 4.80 × 10−8) and peptide cross-linking (P = 1.50 × 10−7). Taken together, our results detected multiple novel candidate genes for psoriasis, providing clues for understanding the genetic mechanism of psoriasis.

Genome-wide association studies (GWASs) have reproducibly associated the SNP rs12454712 with waist-to-hip ratio adjusted for body mass index (WHRadjBMI), but the functional role underlying this intronic variant is unknown. Integrative genomic and epigenomic analyses supported rs12454712 as a functional independent variant. We further demonstrated that rs12454712 acted as an allele-specific enhancer regulating expression of its located gene BCL2 by using dual-luciferase reporter assays and CRISPR-Cas9. Specifically, rs12454712-C allele can bind transcription factor ZNF329, which efficiently elevates the enhancer activity and increases BCL2 expression. Knocking down Bcl2 in 3T3-L1 cells led to the down-regulation of adipogenic differentiation marker genes and increased cell apoptosis. Significant negative correlation between BCL2 expression in subcutaneous adipose tissues and obesity was observed. Our findings illustrate the molecular mechanisms behind the intronic SNP rs12454712 for central obesity, which would be a potential and promising target for developing appropriate therapies.

Genome-wide association studies (GWAS) have reproducibly associated the single nucleotide polymorphism (SNP) rs12454712 with waist-to-hip ratio adjusted for BMI (WHRadjBMI), but the functional role underlying this intronic variant is unknown. Integrative genomic and epigenomic analyses supported rs12454712 as a functional independent variant. We further demonstrated that rs12454712 acted as an allele-specific enhancer regulating expression of its located gene

Osteoporosis is a typical polygenic disease, and its heritability is as high as 85%. The incidence of osteoporosis has jumped to the fifth among the common diseases. Although a large number of osteoporosis-susceptible SNPs have been identified, most of them are in the non-coding regions of the genome and the functional mechanisms are unknown. The purpose of this study was to explore the function of non-coding osteoporosis-susceptible SNP rs4325274 and dissect the molecular regulatory mechanisms through integrating bioinformatics analysis and functional experiments. Firstly, we found the SNP rs4325274 resided in a putative enhancer element through functional annotation. eQTL and Hi-C analysis found that the SOX6 gene might be a potential distal target of rs4325274. We conducted the motif prediction using multiple databases and verified the result using ChIP-seq data from GEO database. The result showed that the transcription factor HNF1A could preferentially bind to SNP rs4325274-G allele. We further demonstrated that SNP rs4325274 acted as an enhancer regulating SOX6 gene expression by using dual-luciferase reporter assays. Knockdown of HNF1A decreased the SOX6 gene expression. Taken together, our results uncovered a new mechanism of a non-coding functional SNP rs4325274 as a distal enhancer to modulate SOX6 expression, which provides new insights into deciphering molecular regulatory mechanisms underlying non-coding susceptibility SNPs on complex diseases.骨质疏松症是一种典型的多基因复杂疾病,遗传力高达85%,其发病率已跃居常见疾病的第5位。尽管已经鉴定出大量骨质疏松易感SNP,但大多数SNP位点位于基因组非编码区,且功能机制未知。本研究旨在通过生物信息学分析和功能实验探究骨质疏松非编码功能性易感SNP rs4325274的分子调控机制。首先,通过表观注释发现该SNP所在区域处在增强子上,eQTL和Hi-C分析结果发现SNP调控的潜在靶基因是SOX6;然后,利用多种数据库进行Motif预测,并结合GEO数据库中的ChIP-seq数据分析进行了验证,结果发现转录因子HNF1A更倾向于结合SNP rs4325274-G碱基;进一步通过双荧光素酶报告基因实验验证了该SNP对SOX6基因表达的增强作用;最后,利用shRNA敲低转录因子HNF1A实验,检测靶基因SOX6的表达变化。以上研究结果初步解析了非编码区功能性SNPrs4325274作为增强子远程调控SOX6基因表达的分子机制,为复杂疾病非编码易感SNP的遗传调控研究提供新思路。.

BackgroundCoronavirus disease 2019 (COVID-19) is a global pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2). It has been found that coronary artery disease (CAD) is a comorbid condition for COVID-19. As the risk factors of CAD, whether blood lipids levels are causally related to increasing susceptibility and severity of COVID-19 is still unknown.DesignWe performed two-sample Mendelian Randomization (MR) analyses to explore whether dyslipidemia, low density lipoprotein cholesterol (LDL-c), high density lipoprotein cholesterol (HDL-c), triglyceride (TG) and total cholesterol (TC) were causally related to COVID-19 risk and severity. The GWAS summary data of blood lipids involving in 188,578 individuals and dyslipidemia in a total of 53,991 individuals were used as exposures, respectively. Two COVID-19 GWASs including 1,221 infected patients and 1,610 severe patients defined as respiratory failure were employed as outcomes. Based on the MR estimates, we further carried out gene-based and gene-set analysis to explain the potential mechanism for causal effect.ResultsThe MR results showed that dyslipidemia was casually associated with the susceptibility of COVID-19 and induced 27% higher odds for COVID-19 infection (MR-IVW OR = 1.27, 95% CI: 1.08 to 1.49, p-value = 3.18 × 10−3). Moreover, the increasing level of blood TC will raise 14 % higher odds for the susceptibility of COVID-19 (MR-IVW OR = 1.14, 95% CI: 1.04 to 1.25, p-value = 5.07 × 10−3). Gene-based analysis identified that ABO gene was associated with TC and the gene-set analysis found that immune processes were involved in the risk effect of TC.ConclusionsWe obtained three conclusions: 1) Dyslipidemia is casually associated with the susceptibility of COVID-19; 2) TC is a risk factor for the susceptibility of COVID-19; 3) The different susceptibility of COVID-19 in specific blood group may be partly explained by the TC concentration in diverse ABO blood groups.

Human mesenchymal stem cells (hMSCs) can be differentiated into adipocytes and osteoblasts. While the transcriptomic and epigenomic changes during adipogenesis and osteogenesis have been characterized, what happens to the chromatin loops is hardly known. Here we induced hMSCs to adipogenic and osteogenic differentiation, and performed 2 kb resolution Hi-C experiments for loop detection and generated RNA-seq, histone modification ChIP-seq and ATAC-seq data for integrative analysis before and after differentiation. We quantitatively identified differential contact loops and unique loops. After integrating with multi-omics data, we demonstrate that strengthened loops after differentiation are associated with gene expression activation. Specially, unique loops are linked with cell fate determination. We also proposed loop-mediated regulatory networks and identified IRS2 and RUNX2 as being activated by cell-specific loops to facilitate adipocytes and osteoblasts commitment, respectively. These results are expected to help better understand the long-range regulation in controlling hMSC differentiation, and provide novel targets for studying adipocytes and osteoblasts determination.

RANKL is a key regulator involved in bone metabolism, and a drug target for osteoporosis. The clinical diagnosis and assessment of osteoporosis are mainly based on bone mineral density (BMD). Previous powerful genomewide association studies (GWASs) have identified multiple intergenic single-nucleotide polymorphisms (SNPs) located over 100 kb upstream of RANKL and 65 kb downstream of AKAP11 at 13q14.11 for osteoporosis. Whether these SNPs exert their roles on osteoporosis through RANKL is unknown. In this study, we conducted integrative analyses combining expression quantitative trait locus (eQTL), genomic chromatin interaction (high-throughput chromosome conformation capture [Hi-C]), epigenetic annotation, and a series of functional assays. The eQTL analysis identified six potential functional SNPs (rs9533090, rs9594738, r8001611, rs9533094, rs9533095, and rs9594759) exclusively correlated with RANKL gene expression (p

Animal-based studies have reported a decrease in bone mass resulting from high level of fibroblast growth factor 21 (FGF21). However, the correlation between plasma FGF21 levels and bone mineral density (BMD) is paradoxical in previous human-based studies, and the associations between FGF21 gene polymorphisms and BMD haven’t been reported yet. Therefore, here, we evaluated plasma FGF21 levels with sufficient study samples, and performed genetic association test to reveal the physiological and genetic role of FGF21 on BMD in adults. Plasma and genetic samples containing 168 and 569 Han Chinese subjects, respectively, were employed in this study. Fasting plasma FGF21 levels were determined using enzyme-linked immunosorbent assay (ELISA). Regional BMD values were measured by dual energy X-ray absorptiometry (DXA). Five variants of FGF21 gene were successfully genotyped. Physiological association suggested that plasma FGF21 levels were inversely correlated with BMD in femoral neck (Neck-BMD: P = 0.039) and Ward’s triangle (Ward’s-BMD: P = 0.002) of hip region. A FGF21 gene variant, rs490942, was significantly associated with the increase of Ward’s-BMD in total (P = 0.027) and female (P = 0.016) cohorts, as well as Neck-BMD in female cohort (P = 7.45 × 10−3). Meanwhile, eQTL results indicated that this SNP was related to the decreased level of FGF21 gene expression. Taking together from both physiological and genetic levels, we suggest that FGF21 is inversely associated with regional BMD. And we haven’t observed sex-specific effect in this study.

Previous studies have identified FGF2 as a susceptibility gene for osteoporosis in Caucasians. Evaluating the genetic associations in different ethnicities is necessary. Moreover, elucidating the functional mechanism for the susceptibility loci is important to offer new targets for therapeutic studies. Here, we genotyped 10 SNPs in FGF2 and tested for associations with bone mineral density (BMD) in a discovery sample of 1,300 Chinese subjects. Nominally significant results were subjected to replication in another sample of 1,039 Chinese subjects. We identified one SNP rs1048201:C>T in FGF2 3′untranslated region significantly associated with spine BMD (combined cohorts, P = 1.53×10−3). Expression quantitative trait locus analyses revealed that rs1048201 also affected FGF2 gene expression (P = 7.03×10−4). Bioinformatics prediction suggested that rs1048201 T allele could disrupt miRNA binding. Luciferase assay validated that the C allele had a repressive effect on FGF2 gene expression. We found that hsa-miR-196a-3p affected expression on both mRNA and protein levels of FGF2. In conclusion, our study provided evidence that a functional SNP rs1048201 was associated with BMD, and SNP rs1048201:C>T variant may act by affecting binding of hsa-miR-196a-3p. The SNP-modified posttranscriptional gene regulation by miRNA could be a potentially pathogenetic mechanism of osteoporosis.

With ENCODE epigenomic data and results from published genome-wide association studies (GWASs), we aimed to find regulatory signatures of obesity genes and discover novel susceptibility genes.Obesity genes were obtained from public GWAS databases and their promoters were annotated based on the regulatory element information. Significantly enriched or depleted epigenomic elements in the promoters of obesity genes were evaluated and all human genes were then prioritized according to the existence of the selected elements to predict new candidate genes. Top-ranked genes were subsequently applied to validate their associations with obesity-related traits in three independent in-house GWAS samples.We identified RAD21 and EZH2 as over-represented, and STAT2 (signal transducer and activator of transcription 2) and IRF3 (interferon regulatory transcription factor 3) as depleted transcription factors. Histone modification of H3K9me3 and chromatin state segmentation of 'poised promoter' and 'repressed' were over-represented. All genes were prioritized and we selected the top five genes for validation at the population level. Combining results from the three GWAS samples, rs7522101 in ESRRG (estrogen-related receptor-γ) remained significantly associated with body mass index after multiple testing corrections (P=7.25 × 10(-5)). It was also associated with β-cell function (P=1.99 × 10(-3)) and fasting glucose level (P0.05) in the meta-analyses of glucose and insulin-related traits consortium (MAGIC) data set.Cnoclusions:In summary, we identified epigenomic characteristics for obesity genes and suggested ESRRG as a novel obesity-susceptibility gene.

Both Systemic Lupus Erythematosus (SLE) and Systemic Sclerosis (SSc) are autoimmune diseases sharing similar genetic backgrounds. Genome-wide association studies (GWASs) have constantly disclosed numerous genetic variants conferring to both disease risks at 7q32.1, but the functional mechanisms underlying them are still largely unknown. Through combining fine-mapping and functional epigenomic analyses, we prioritized a potential independent functional SNP (rs13239597) withinTNPO3promoter region, residing in a putative enhancer element. Functional analysis integrating expression quantitative trait locus (eQTL) and high-throughput chromatin interaction (Hi-C) demonstrated thatIRF5is the distal target gene (~118kb) of rs13239597, which is a key regulator of pathogenic autoantibody dysregulation increased risk of both SLE and SSc. We experimentally validated the long-range chromatin interactions between rs13239597 andIRF5using chromosome conformation capture (3C) assay. We further demonstrated that rs13239597-A acted as an allele-specific enhancer regulatingIRF5expression, independently ofTNPO3by using dual-luciferase reporter assays and CRISPR-Cas9. Particularly, the transcription factor EVI1 could preferentially bind to rs13239597-A allele and increase the enhancer activity to regulateIRF5expression. Taken together, our results uncovered the mechanistic insight connecting between a noncoding functional variant with a distal immunologically pathogenic geneIRF5, which might obligate in understanding the complex genetic architectures of SLE and SSc pathogenesis.

Both systemic lupus erythematosus (SLE) and systemic sclerosis (SSc) are autoimmune diseases sharing similar genetic backgrounds. Genome-wide association studies have constantly disclosed numerous genetic variants conferring to both disease risks at 7q32.1, but the functional mechanisms underlying them are still largely unknown. Through a series of bioinformatics and functional analyses, we prioritized a potential independent functional single-nucleotide polymorphism (rs13239597) within TNPO3 promoter region, residing in a putative enhancer element and validated that IRF5 is the distal target gene (∼118 kb) of rs13239597, which is a key regulator involved in pathogenic autoantibody dysregulation, increasing risk of both SLE and SSc. We experimentally validated the long-range chromatin interactions between rs13239597 and IRF5 using chromosome conformation capture assay. We further demonstrated that rs13239597-A acted as an allele-specific enhancer regulating IRF5 expression, independently of TNPO3 by using dual-luciferase reporter assays and CRISPR-Cas9. Particularly, the transcription factor EVI1 could preferentially bind to rs13239597-A allele and increase the enhancer activity to regulate IRF5 expression. Taken together, our results uncovered a mechanistic insight of a noncoding functional variant acting as an allele-specific distal enhancer to directly modulate IRF5 expression, which might obligate in understanding of complex genetic architectures of SLE and SSc pathogenesis.

Genome-wide association studies (GWASs) have reproducibly associated variants within intergenic regions of 1p36.12 locus with osteoporosis, but the functional roles underlying these noncoding variants are unknown. Through an integrative functional genomic and epigenomic analyses, we prioritized rs6426749 as a potential causal SNP for osteoporosis at 1p36.12. Dual-luciferase assay and CRISPR/Cas9 experiments demonstrate that rs6426749 acts as a distal allele-specific enhancer regulating expression of a lncRNA (LINC00339) (∼360 kb) via long-range chromatin loop formation and that this loop is mediated by CTCF occupied near rs6426749 and LINC00339 promoter region. Specifically, rs6426749-G allele can bind transcription factor TFAP2A, which efficiently elevates the enhancer activity and increases LINC00339 expression. Downregulation of LINC00339 significantly increases the expression of CDC42 in osteoblast cells, which is a pivotal regulator involved in bone metabolism. Our study provides mechanistic insight into how a noncoding SNP affects osteoporosis by long-range interaction, a finding that could indicate promising therapeutic targets for osteoporosis.

RANKL is a key regulator involved in bone metabolism, and a drug target for osteoporosis. The clinical diagnosis and assessment of osteoporosis are mainly based on bone mineral density (BMD). Previous powerful genomewide association studies (GWASs) have identified multiple intergenic single-nucleotide polymorphisms (SNPs) located over 100 kb upstream of RANKL and 65 kb downstream of AKAP11 at 13q14.11 for osteoporosis. Whether these SNPs exert their roles on osteoporosis through RANKL is unknown. In this study, we conducted integrative analyses combining expression quantitative trait locus (eQTL), genomic chromatin interaction (high-throughput chromosome conformation capture [Hi-C]), epigenetic annotation, and a series of functional assays. The eQTL analysis identified six potential functional SNPs (rs9533090, rs9594738, r8001611, rs9533094, rs9533095, and rs9594759) exclusively correlated with RANKL gene expression (p 0.001) at 13q14.11. Co-localization analyses suggested that eQTL signal for RANKL and BMD-GWAS signal shared the same causal variants. Hi-C analysis and functional annotation further validated that the first five osteoporosis SNPs are located in a super-enhancer region to regulate the expression of RANKL via long-range chromosomal interaction. Particularly, dual-luciferase assay showed that the region harboring rs9533090 in the super-enhancer has the strongest enhancer activity, and rs9533090 is an allele-specific regulatory SNP. Furthermore, deletion of the region harboring rs9533090 using CRISPR/Cas9 genome editing significantly reduced RANKL expression in both mRNA level and protein level. Finally, we found that the rs9533090-C robustly recruits transcription factor NFIC, which efficiently elevates the enhancer activity and increases the RANKL expression. In summary, we provided a feasible method to identify regulatory noncoding SNPs to distally regulate their target gene underlying the pathogenesis of osteoporosis by using bioinformatics data analyses and experimental validation. Our findings would be a potential and promising therapeutic target for precision medicine in osteoporosis. © 2018 American Society for Bone and Mineral Research.

Genetic variation of four strains of Meretrix meretrix,thin checkered(TC),black spot(BS),dark fringe(DF)and red shell(RS)was studied.Thirty randomly selected individuals from each strain and nine polymorphic microsatellite loci were used for genetic analysis.A total of 105 alleles were identified,the most alleles were 21(WG07)and the least locus were 7(WG11).The distribution of the alleles for the same loci was different in different strains and specific allele types were detected in each strains.All the microsatellites were highly polymorphic,and various genetic variability measures,including observed heterozygosity(0.486 to 0.867),expected heterozygosity(0.110 to 1.000),and polymorphism information content(0.433 to 0.834),Chi-square tests showed that most of the cases in four strains deviated from Hardy-Weinberg equilibrium.Pairwise FST ranged from 0.005 to 0.269.Genetic distances among strains ranged from 0.052 0 to 0.098 0.The results of cluster analysis indicated that TC strain had higher genetic difference than other strains,then was BS strain,and the genetic variation between DF and RS strains was relatively lower.