钙敏感受体基因、白介素6基因与中国人群骨密度相关联

钙敏感受体是钙新陈代谢的一个重要因素,白介素6是参与破骨细胞分化及功能的一种多效细胞因子。因此,钙敏感受体基因和白介素6基因都为骨矿物质代谢的重要候选基因。本研究旨在利用数量性状传递不平衡检测法,检测白介素6基因和钙敏感受体基因与腰椎和髋部骨密度的关联和连锁,以证实它们是否为影响中国人群骨密度的重要候选基因。本研究的样本为来自中国上海的401个中国核心家庭,共1,263个个体,均为汉族。每个核心家庭由父母双亲和至少一个20～45岁的健康绝经前女儿组成。腰椎与髋部的骨密度采用Hologic QDR 2000＋双能X射线扫描仪进行了检测。用PE377测序仪及相关软件分别对白介素6和钙敏感受体基因中的一个CA重复多态微卫星位点进行了基因分型。分析结果表明钙敏感受体基因（CA）12等位基因（P=0．006）及（Ca）18等位基因（P=0．02）与股骨颈骨密度之间存在显著的整体关联。白介素6基因的（CA）18等位基因与整个髋部（P=0．021）、股骨颈（P=0．041）以及转子间区（P=0．029）骨密度之间均存在显著的家庭内关联。白介素6基因（CA）n位点与腰椎BMD之间存在显著的连锁（P=0．001）。本研究结果表明白介素6基因和钙敏感受体基因可能为与中国人群骨密度变异相关联的候选基因。     

Non-synonymous polymorphisms in the P2RX 4 are related to bone mineral density and osteoporosis risk in a cohort of Dutch fracture patients

In the present study we investigated whether single nucleotide polymorphisms (SNPs) in the P2RX₄, which alter the P2X₄R function, are associated with the development of osteoporosis and whether an interaction between the P2X₄R and P2X₇R confer a synergistic effect of these two receptors on osteoporosis risk. Patients with fracture (690 females and 231 males, aged ≥50 years) were genotyped for three non-synonymous P2X₄R SNPs. Bone mineral density (BMD) was measured at the total hip, lumbar spine, and femoral neck. Subject carrying the variant allele of the Tyr315Cys polymorphism showed a 2.68-fold (95 % CI, 1.20–6.02) higher risk of osteoporosis compared with wild-type subject. Furthermore, significant lower lumbar spine BMD values were observed in subjects carrying the Cys315 allele as compared with wild-type (0.85 ± 0.17 and 0.93 ± 0.17 g/cm², respectively; p < 0.001). Assuming a recessive model, carriers of the variant allele of the Ser242Gly polymorphism showed increased BMD values at the lumbar spine compare to wild-type subject (1.11 ± 0.35 and 0.92 ± 0.17 g/cm², respectively; p = 0.0045). This is the first study demonstrating an association of non-synonymous polymorphisms in the P2RX₄ and the risk of osteoporosis, suggesting a role of the P2X₄R in the regulation of bone mass.

Electronic supplementary material

The online version of this article (doi:10.1007/s11302-012-9337-0) contains supplementary material, which is available to authorized users.     

The -607C/A Polymorphisms in Interleukin-18 Gene Promoter Contributes to Cancer Risk: Evidence from A Meta-Analysis of 22 Case-Control Studies

Background

Several observational studies have investigated the association between -607 C/A polymorphism of IL-18 gene and cancer risk; however, the results were inconsistent. Therefore, we performed a meta-analysis to derive a more precise estimation of the association to help us better understand the relationship between -607 C/A polymorphism of IL-18 gene promoter and risk of cancer.

Methods

A literature search was carried out using PubMed, EMBASE, and China National Knowledge Infrastructure (CNKI) database between January 1966 and February 2013. Fixed-effect and random-effect models were used to estimate the pooled odds ratio (OR) and the corresponding 95% confidence intervals (CIs).

Results

A total of 22 case-control studies including 4100 cancer cases and 4327 controls contributed to the analysis. Significant association between -607C/A polymorphism in IL-18 gene promoter and cancer risk was observed (CA vs CC:OR =1.221, 95% CI: 1.096, 1.360; P_{heterogeneity}=0.219; AA/CA vs. CC:OR =1.203, 95% CI: 1.057, 1.369; P_{heterogeneity}=0.064). In the subgroup analysis by ethnicity, -607C/A polymorphism significantly increased risk of cancer among Asian population (AA/CA vs. CC:OR =1.197, 95% CI: 1.023,1.401; P_{heterogeneity}=0.088); however, no significant association was found in Caucasian or African population. The -607C/A polymorphism was associated with a significantly increased risk of nasopharyngeal carcinoma (CA vs CC:OR =1.330, 95% CI: 1.029,1.719; P_{heterogeneity}=0.704; AA/CA vs. CC:OR =1.323, 95% CI: 1.037,1.687; P_{heterogeneity}=0.823) and esophageal cancer (AA/CA vs. CC:OR =1.289, 95% CI: 1.002,1.658; P_{heterogeneity}=0.700).

Conclusions

The present meta-analysis suggests that the -607C/A polymorphisms in IL-18 gene promoter is associated with a significantly increased risk of cancer, especially for nasopharyngeal carcinoma and esophageal cancer and in Asian population. More studies with larger sample size, well controlled confounding factors are warranted to validate this association.     

The (GT) n polymorphism and haplotype of the COL1A2 gene, but not the (AAAG) n polymorphism of the PTHR1 gene, are associated with bone mineral density in Chinese

Collagen type I 2 (COL1A2) and parathyroid hormone (PTH)/PTH-related peptide receptor (PTHR1) are two prominent candidate genes for bone mineral density (BMD). To test their importance for BMD variation in Chinese, we recruited 388 nuclear families composed of both parents and at least one healthy daughter with a total of 1,220 individuals, and simultaneously analyzed population stratification, total-family association, and within-family association between BMD at the spine and hip and the (GT)_n marker in the intron 1 of the COL1A2 gene and the (AAAG)_n marker in the P3 promoter of PTHR1 gene. We also performed these association analyses with haplotypes of the MspI and (GT)_n polymorphisms in the COL1A2 gene. Significant within-family association was found between the M(GT)₁₂ haplotype and trochanter BMD (P<0.001). Individuals with this haplotype have, on average, 9.53% lower trochanter BMD than the non-carriers. Suggestive evidence of the within-family association was detected between the (GT)₁₇ allele and BMD at the spine (P=0.012), hip (P=0.011), femoral neck (P=0.032), trochanter (P=0.023), and intertrochanter (P=0.034). The association was confirmed by subsequent permutation tests. For the association, the proportion of phenotypic variance explained by the detected markers ranged from 1.2 to 3.9%, with the highest 3.9% at the trochanter for the M(GT)₁₂ haplotype. This association indicates that there is strong linkage disequilibrium between the polymorphisms (MspI and GT repeat polymorphism) in the COL1A2 gene and a nearby quantitative trait locus (QTL) underlying BMD variation in Chinese, or the markers themselves may have an important effect on the variation of BMD. On the other hand, no significant within-family association, population stratification and total-family association between the PTHR1 polymorphism and BMD were found in our Chinese population.S.-F. Lei and F.-Y. Deng contributed equally to this work     

CYP19A1 polymorphisms are associated with bone mineral density in Chinese men

Aromatase-dependent biosynthesis of estrogen plays an important role in maintenance of the male skeleton, and Cytochrome p450 aromatase is the key enzyme to catalyze the conversion of androgen precursors to estrogens. We investigated the association of polymorphisms in the CYP19A1 gene and bone mineral density in a Chinese cohort. 2392 extreme low femoral neck BMD cases or extreme high femoral neck BMD controls were selected from a population-based cohort and genotyped for eight SNPs in the CYP19A1 gene. Significant associations for rs17703883, rs12594287 and rs16964201 SNPs with BMD were found in men only. Men with TC/CC genotypes in the rs17703883 SNP had a 1.5 times higher risk of having extreme low femoral neck BMD (P = 0.003, empirical P value = 0.05), and decreased BMDs at total body (P = 0.004, empirical P value = 0.07) and total hip (P = 0.003, empirical P value = 0.05). Men carrying AA/AG genotypes in the rs12594287 SNP had a 30% reduced risk of having extreme low femoral neck BMD (P = 0.007, empirical P value = 0.12), and increased BMDs at total body (P = 0.0009, empirical P value = 0.018) and total hip (P = 0.001, empirical P value = 0.02). Men carrying TT/TC genotypes in the rs16964201 SNP had a 40% reduced risk of having extreme low femoral neck BMD (P = 0.005, empirical P value = 0.087), and increased BMDs at total body (P = 0.0001, empirical P value = 0.002) and total hip (P = 0.0006, empirical P value = 0.012). Haplotype analysis showed that the G-C-T-A-T haplotype was significantly related to higher BMD. Our finding suggests that genetic variations in the CYP19A1 gene are significantly associated with BMD at different skeletal sites in adult men, but not in women.     

雌激素受体β基因CA重复序列多态性与绝经后骨质疏松症的关联性研究

绝经后骨质疏松症(PMO)是一种多基因调控的遗传性疾病。雌激素受体β亚型基因是骨质疏松症的重要侯选基因。此文采用病例对照设计(78名股骨颈PMO病人和122名对照以及108名腰椎PMO病人和92名对照)研究中国人(汉族)雌激素受体β基因(ESR2)第5内含子CA重复序列多态性与PMO的相关性。以CA重复序列平均数22次为界将重复序列基因分为短基因(<22)和长基因(≥22),分别以S和L表示。股骨颈及腰椎(L2-4)部位,病例组中LL基因型和L等位基因者频率显著高于对照组(P<0.01),SL、LL及SL LL基因型者较SS基因型者患PMO风险显著增高(P<0.05);调整年龄、绝经时间、绝经年龄及体质指数后,Logistic回归分析显示ESR2(CA)n多态性仍然与股骨颈(OR4.923,95%CI1.986～12.203,P=0.001)及L2-4(OR2.267,95%CI1.121～4.598,P=0.023)PMO显著相关。结果显示:ESR2基因CA重复序列多态性与股骨颈和L2-4部位PMO独立关联,L等位基因显性影响PMO的发病风险。     

Association of P2Y2 receptor SNPs with bone mineral density and osteoporosis risk in a cohort of Dutch fracture patients

The P2Y₂ receptor is a G-protein-coupled receptor with adenosine 5′-triphosphate (and UTP) as natural ligands. It is thought to be involved in bone physiology in an anti-osteogenic manner. As several non-synonymous single nucleotide polymorphisms (SNPs) have been identified within the P2Y₂ receptor gene in humans, we examined associations between genetic variations in the P2Y₂ receptor gene and bone mineral density (BMD) (i.e., osteoporosis risk), in a cohort of fracture patients. Six hundred and ninety women and 231 men aged ≥50 years, visiting an osteoporosis outpatient clinic at Maastricht University Medical Centre for standard medical follow-up after a recent fracture, were genotyped for three non-synonymous P2Y₂ receptor gene SNPs. BMD was measured at three locations (total hip, lumbar spine, and femoral neck) using dual-energy X-ray absorptiometry. Differences in BMD between different genotypes were tested using analysis of covariance. In women, BMD values at all sites were significantly different between the genotypes for the Leu46Pro polymorphism, with women homozygous for the variant allele showing the highest BMD values (0.05 > p > 0.01). The Arg312Ser and Arg334Cys polymorphisms showed no differences in BMD values between the different genotypes. This is the first report that describes the association between the Leu46Pro polymorphism of the human P2Y₂ receptor and the risk of osteoporosis.     

Diversifying Sunflower Germplasm by Integration and Mapping of a Novel Male Fertility Restoration Gene

The combination of a single cytoplasmic male-sterile (CMS) PET-1 and the corresponding fertility restoration (Rf) gene Rf₁ is used for commercial hybrid sunflower (Helianthus annuus L., 2n = 34) seed production worldwide. A new CMS line 514A was recently developed with H. tuberosus cytoplasm. However, 33 maintainers and restorers for CMS PET-1 and 20 additional tester lines failed to restore the fertility of CMS 514A. Here, we report the discovery, characterization, and molecular mapping of a novel Rf gene for CMS 514A derived from an amphiploid (Amp H. angustifolius/P 21, 2n = 68). Progeny analysis of the male-fertile (MF) plants (2n = 35) suggested that this gene, designated Rf₆, was located on a single alien chromosome. Genomic in situ hybridization (GISH) indicated that Rf₆ was on a chromosome with a small segment translocation on the long arm in the MF progenies (2n = 34). Rf₆ was mapped to linkage group (LG) 3 of the sunflower SSR map. Eight markers were identified to be linked to this gene, covering a distance of 10.8 cM. Two markers, ORS13 and ORS1114, were only 1.6 cM away from the gene. Severe segregation distortions were observed for both the fertility trait and the linked marker loci, suggesting the possibility of a low frequency of recombination or gamete selection in this region. This study discovered a new CMS/Rf gene system derived from wild species and provided significant insight into the genetic basis of this system. This will diversify the germplasm for sunflower breeding and facilitate understanding of the interaction between the cytoplasm and nuclear genes.     

Linkage and Association Between CA Repeat Polymorphism of the TNFR2 Gene and Obesity Phenotypes in Two Independent Caucasian Populations

Previously, our group has reported a suggestive linkage evidence of 1p36 with body mass index (BMI) (LOD = 2.09). The tumor necrosis factor receptor 2 (TNFR2) at 1p36 is an excellent positional and functional candidate gene for obesity. In this study, we have investigated the linkage and association between the TNFR2 gene and obesity phenotypes in two large independent samples, using the quantitative transmission disequilibrium tests (QTDT). The first group was made up of 1 836 individuals from 79 multi-generation pedigrees. The second group was a randomly ascertained set of 636 individuals from 157 US Caucasian nuclear families. Obesity phenotypes tested include BMI, fat mass, and percentage fat mass (PFM). A significant result (P = 0.0056) was observed for linkage with BMI in the sample of the multigenerational pedigrees. Our data support the TNFR2 gene as a quantitative trait locus (QTL) underlying BMI variation in the Caucasian populations.     

Genetic Analysis Identifies DDR2 as a Novel Gene Affecting Bone Mineral Density and Osteoporotic Fractures in Chinese Population

DDR2 gene, playing an essential role in regulating osteoblast differentiation and chondrocyte maturation, may influence bone mineral density (BMD) and osteoporosis, but the genetic variations actually leading to the association remain to be elucidated. Therefore, the aim of this study was to investigate whether the genetic variants in DDR2 are associated with BMD and fracture risk. This study was performed in three samples from two ethnicities, including 1,300 Chinese Han subjects, 700 Chinese Han subjects (350 with osteoporotic hip fractures and 350 healthy controls) and 2,286 US white subjects. Twenty-eight SNPs in DDR2 were genotyped and tested for associations with hip BMD and fractures. We identified 3 SNPs in DDR2 significantly associated with hip BMD in the Chinese population after multiple testing adjustments, which were rs7521233 (P = 1.06×10⁻⁴, β: −0.018 for allele C), rs7553831 (P = 1.30×10⁻⁴, β: −0.018 for allele T), and rs6697469 (P = 1.59×10⁻³, β: −0.015 for allele C), separately. These three SNPs were in high linkage disequilibrium. Haplotype analyses detected two significantly associated haplotypes, including one haplotype in block 2 (P = 9.54×10⁻⁴, β: −0.016) where these three SNPs located. SNP rs6697469 was also associated with hip fractures (P = 0.043, OR: 1.42) in the Chinese population. The effect on fracture risk was consistent with its association with lower BMD. However, in the white population, we didn’t observe significant associations with hip BMD. eQTL analyses revealed that SNPs associated with BMD also affected DDR2 mRNA expression levels in Chinese. Our findings, together with the prior biological evidence, suggest that DDR2 could be a new candidate for osteoporosis in Chinese population. Our results also reveal an ethnic difference, which highlights the need for further genetic studies in each ethnic group.     

Test for positional candidate genes for body composition on pig chromosome 6

One QTL affecting backfat thickness (BF), intramuscular fat content (IMF) and eye muscle area (MA) was previously localized on porcine chromosome 6 in an F₂ cross between Iberian and Landrace pigs. This work was done to study the effect of two positional candidate genes on these traits: H-FABP and LEPR genes. The QTL mapping analysis was repeated with a regression method using genotypes for seven microsatellites and two PCR-RFLPs in the H-FABP and LEPR genes. H-FABP and LEPR genes were located at 85.4 and 107 cM respectively, by linkage analysis. The effects of the candidate gene polymorphisms were analyzed in two ways. When an animal model was fitted, both genes showed significant effects on fatness traits, the H-FABP polymorphism showed significant effects on IMF and MA, and the LEPR polymorphism on BF and IMF. But when the candidate gene effect was included in a QTL regression analysis these associations were not observed, suggesting that they must not be the causal mutations responsible for the effects found. Differences in the results of both analyses showed the inadequacy of the animal model approach for the evaluation of positional candidate genes in populations with linkage disequilibrium, when the probabilities of the parental origin of the QTL alleles are not included in the model.     

Genetic variations of the porcine PRKAG3 gene in Chinese indigenous pig breeds

Four missense substitutions (T30N, G52S, V199I and R200Q) in the porcine PRKAG3 gene were considered as the likely candidate loci affecting meat quality. In this study, the R200Q substitution was investigated in a sample of 62 individuals from Hampshire, Chinese Min and Erhualian pigs, and the genetic variations of T30N, G52S and V199I substitutions were detected in 1505 individuals from 21 Chinese indigenous breeds, 5 Western commercial pig breeds, and the wild pig. Allele 200R was fixed in Chinese Min and Erhualian pigs. Haplotypes II-QQ and IV-QQ were not observed in the Hampshire population, supporting the hypothesis that allele 200Q is tightly linked with allele 199V. Significant differences in allele frequencies of the three substitutions (T30N, G52S and V199I) between Chinese indigenous pigs and Western commercial pigs were observed. Obvious high frequencies of the "favorable" alleles 30T and 52G in terms of meat quality were detected in Chinese indigenous pigs, which are well known for high meat quality. However, the frequency of the "favorable" allele 199I, which was reported to have a greater effect on meat quality in comparison with 30T and 52G, was very low in all of the Chinese indigenous pigs except for the Min pig. The reasons accounting for this discrepancy remain to be addressed. The presence of the three substitutions in purebred Chinese Tibetan pigs indicates that the three substitutions were ancestral mutations. A novel A/G substitution at position 51 in exon 1 was identified. The results suggest that further studies are required to investigate the associations of these substitutions in the PRKAG3 gene with meat quality of Chinese indigenous pigs, and to uncover other polymorphisms in the PRKAG3 gene with potential effects on meat quality in Chinese indigenous pigs.     

The fat mass and obesity associated gene, FTO, is also associated with osteoporosis phenotypes

Obesity and osteoporosis are closely correlated genetically. FTO gene has been consistently identified to be associated with obesity phenotypes. A recent study reported that the mice lacking Fto could result in lower bone mineral density (BMD). Thus, we hypothesize that the FTO gene might be also important for osteoporosis phenotypes. To test for such a hypothesis, we performed an association analyses to investigate the relationship between SNPs in FTO and BMD at both hip and spine. A total of 141 SNPs were tested in two independent Chinese populations (818 and 809 unrelated Han subjects, respectively) and a Caucasian population (2,286 unrelated subjects). Combining the two Chinese samples, we identified 6 SNPs in FTO to be significantly associated with hip BMD after multiple testing adjustments, with the combined P values ranged from 4.99×10⁻⁴–1.47×10⁻⁴. These 6 SNPs are all located at the intron 8 of FTO and in high linkage disequilibrium. Each copy of the minor allele of each SNP was associated with increased hip BMD values with the effect size (beta) of ∼0.025 and ∼0.015 in the Chinese sample 1 and 2, respectively. However, none of these 6 SNPs showed significant association signal in the Caucasian sample, by presenting some extent of ethnic difference. Our findings, together with the prior biological evidence, suggest that the FTO gene might be a new candidate for BMD variation and osteoporosis in Chinese populations.     

Increased Bone Mineral Density in Male Patients With Idiopathic Hypogonadotropic Hypogonadism Who Undergo Sex Hormone Therapy: Findings From Cross-Sectional and Longitudinal Studies

ObjectiveThis retrospective observational study assessed the long-term impact of pulsatile gonadotropin-releasing hormone, combined gonadotropin, or testosterone replacement therapy on total hip, femoral, and lumbar bone mineral density (BMD) and Z-scores in adult men with idiopathic hypogonadotropic hypogonadism (IHH).MethodsIn the cross-sectional study, 69 patients were allocated to untreated (n = 42) and treated (n = 27) groups. The untreated group included IHH patients without hormone therapy history, while the treated group included age- and body mass index-matched patients who had received hormone therapy for at least 5 years. The longitudinal study included 53 IHH patients, and their hip and lumbar BMDs were measured several times during hormone therapy. We then evaluated the changes in their BMD.ResultsOur cross-sectional study showed that the treated group had a significantly higher BMD and Z-score for total hip, femoral neck, and lumbar spine (P < 0.001 for all) than the untreated group, and the average bone mass even reached the age-matched normal range. The prevalence of low BMD was 80.95% and 11.11% in untreated and treated groups, respectively. In the longitudinal study (N = 53), the total hip, femoral neck, and lumbar spine BMD gradually increased during treatment. The lumbar spine showed a greater increment in BMD compared with the total hip and femoral neck (P < 0.05).ConclusionSex hormone therapy improved hip and lumbar spine BMD and Z-scores in patients with IHH. The lumbar spine showed a greater improvement in BMD compared with the total hip and femoral neck.     

Association between the dopamine D4 receptor gene exon III variable number of tandem repeats and political attitudes in female Han Chinese

Twin and family studies suggest that political attitudes are partially determined by an individual''s genotype. The dopamine D4 receptor gene (DRD4) exon III repeat region that has been extensively studied in connection with human behaviour, is a plausible candidate to contribute to individual differences in political attitudes. A first United States study provisionally identified this gene with political attitude along a liberal–conservative axis albeit contingent upon number of friends. In a large sample of 1771 Han Chinese university students in Singapore, we observed a significant main effect of association between the DRD4 exon III variable number of tandem repeats and political attitude. Subjects with two copies of the 4-repeat allele (4R/4R) were significantly more conservative. Our results provided evidence for a role of the DRD4 gene variants in contributing to individual differences in political attitude particularly in females and more generally suggested that associations between individual genes, and neurochemical pathways, contributing to traits relevant to the social sciences can be provisionally identified.     

Effect of Genetic Variations of the POU1F1 Gene on Growth Traits of Nanyang Cattle

PCR-RFLP was applied to analyze the effect of the genetic variations of the POU1F1 gene on growth traits of 100 Nanyang cattle. The results showed that the 451 bp PCR product digested with Hinf I demonstrated polymorphism in the population, which was at Hardy-Weinberg equilibrium. Moreover, the frequencies of alleles A/B in the Nanyang population were 0.465/0.535. The association of the variations of the POU1F1 gene with the growth traits in the population was analyzed. The following parameters were greater in individuals with a genotype BB than in those with an genotype AB: birth weight, average weight increase before ablactation, body height at 12 months, body weight, body length, and chest girth at 6 months and 12 months (P<0.05). The body weight at 12 months was higher in the BB individuals than in the AA individuals (P <0.05). The body weight and body sizes also showed a trend of allele B> allele A in the other age groups. Therefore, the genotype BB maybe a dominant genotype and the allele B may be a dominant allele. These results imply that the allele B of the POU1F1 gene is likely to positively affect the growth traits.     

Combined effects of collagen type I alpha1 (COL1A1) Sp1 polymorphism and osteoporosis risk factors on bone mineral density in Turkish postmenopausal women

Identification of risk factors for osteoporosis has been essential for understanding the development of osteoporosis. The collagen type I alpha1 (COL1A1) gene is suggested to be implicated in reduced bone mineral density (BMD) in osteoporosis. In the present study, the investigation of the effects of Sp1 polymorphic variants of COL1A1 gene on BMD values, and the determination of the association between COL1A1 Sp1 gene variants and osteoporosis risk factors in the context of gene–environment interaction in Turkish postmenopausal women were aimed. For the detection of COL1A1 Sp1 polymorphism, PCR-RFLP techniques have been used. BMD for lumbar spine (L1–L4) and hip (femoral neck and total hip) was measured by DXA. This study was carried out using a sample of 254 postmenopausal women. We observed a trend decrease in BMD values in the subjects with “ss” genotype having lower BMD of lumbar spine, femoral neck and total hip than those with “SS” and “Ss” genotype, however the differences did not reach statistical significance (P > 0.05). We also found that the frequencies of the BMD under mean values at the femoral neck (57.5%) and total hip (76.2%) increased considerably in the subjects carrying “Ss/ss” genotypes in combination of having family history of osteoporosis (61.5% for femoral neck) and smoking history (90.0% for total hip). This population-based study indicates that COL1A1 Sp1 polymorphism may contribute to the development of osteoporosis in combination of osteoporosis risk factors in Turkish postmenopausal women.     

Population genetic differentiation of Schisandra chinensis and Schisandra sphenanthera as revealed by ISSR analysis

Schisandra chinensis (Turcz.) Baill. and Schisandra sphenanthera Rehd. et Wils. are well-known Chinese medicinal plants. The population genetic variation of the two species was studied using inter simple sequence repeat (ISSR) molecular markers. High levels of genetic diversity are revealed in both S. chinensis (P = 88.36%, h = 0.2894, I = 0.4396) and S. sphenanthera (P = 84.09%, H = 0.2782, I = 0.4280). However, the population genetic differentiation is significantly different between the two species. The S. sphenanthera harbors as high as 27% of the genetic variation among populations but 73% within populations, whereas in S. chinensis 17% of the genetic variation occurs among populations and 83% within populations. Both significant (P < 0.05) heterozygosity excess and shifted mode of allele frequency distribution are detected in four out of six populations of S. chinensis and one out of five populations of S. sphenanthera, suggesting the occurrence of recent population bottlenecks in the two species. The different patterns of genetic variation in S. chinensis and S. sphenanthera are discussed in relation to their differences in pollination mechanism, geographic distribution and historical events, and the level of gene flow and genetic drift.     

我国西南部喀斯特森林特有濒危树种掌叶木新的微卫星分子标记的开发

采用基因组DNA富集文库法FIASCO(Fast isolation by AFLP of sequences containing repeats)从掌叶木(Handeliodendron bodinieri)基因组中分离和筛选了10个新的微卫星位点,进而对掌叶木茂兰自然分布居群的遗传多样性进行了分析。结果表明, 每个位点在30株掌叶木个体上的平均等位基因数(A)为3.5(3~5个),平均观察杂合度(H_O)为0.650(0.267~0.900),平均预期杂合度(H_E)为0.494(0.224~0.652)。每个位点的第一排除概率值P_r(Ex₁)为0.029~0.240,位点综合值为0.7496。单个位点的第二排除概率P_r(Ex₂)为0.123~0.419,位点综合值为0.9517。这些信息预示着这些微卫星标记可以为研究喀斯特特有濒危树种掌叶木的基因流及居群遗传结构提供有效的遗传工具。