Sampling strategy for wild soybean(Glycine soja)populations based on their genetic diversity and fine-scale spatial genetic structure

A total of 892 individuals sampled from a wild soybean population in a natural reserve near the Yellow River estuary located in Kenli of Shandong Province(China)were investigated.Seventeen SSR(simple sequence repeat)primer pairs from cultivated soybeans were used to estimate the genetic diversity of the population and its variation pattern versus changes of the sample size(sub-samples),in addition to investigating the fine-scale spatial genetic structure within the population.The results showed relatively high genetic diversity of the population with the mean value of allele number(A)being 2.88,expected heterozygosity(He)0.431,Shannon diversity index(I)0.699,and percentage of poly-morphic loci(P)100%.Sub-samples of different sizes(ten groups)were randomly drawn from the population and their genetic diversity was calculated by computer simulation.The regression model of the four diversity indexes with the change of sample sizes was computed.As a result,27-52 individuals can reach 95%of total genetic variability of the population.Spatial autocorrelation analysis revealed that the genetic patch size of this wild soybean population is about 18 m.The study provided a scientific basis for the sampling strategy of wild soybean populations.

Fine-scale spatial genetic structure in predominantly selfing plants with limited seed dispersal： a rule or exception？

Gene flow at a fine scale is still poorly understood despite its recognized importance for plant population demographic and genetic processes.We tested the hypothesis that intensity of gene flow will be lower and strength of spatial genetic structure(SGS) will be higher in more peripheral populations because of lower population density.The study was performed on the predominantly selfing Avena sterilis and included:(1) direct measurement of dispersal in a controlled environment;and(2) analyses of SGS in three natural populations,sampled in linear transects at fixed increasing inter-plant distances.We found that in A.sterilis major seed dispersal is by gravity in close(less than 2 m) vicinity of the mother plant,with a minor additional effect of wind.Analysis of SGS with six nuclear SSRs revealed a significant autocorrelation for the distance class of 1 m only in the most peripheral desert population,while in the two core populations with Mediterranean conditions,no genetic structure was found.Our results support the hypothesis that intensity of SGS increases from the species core to periphery as a result of decreased within-population gene flow related to low plant density.Our findings also show that predominant self-pollination and highly localized seed dispersal lead to SGS at a very fine scale,but only if plant density is not too high.

Fine-scale genetic structure of Eremosparton songoricum and implication for conservation

Eremosparton songoricum (Litv.) Vass. is a clonal shrub that reproduces both asexually by under-ground rhizomes and sexually by seeds. It is now a rare species with a narrow distribution in fragmented habitat patches in the Gurbantunggut Desert of Xinjiang, China. The objective of this study was to determine the spatial pattern or structure of genetic variation within population. The within-populations genetic structure of E. songoricum in a plot (10 m×10 m) was analyzed using inter simple sequence repeats (ISSR) markers. Correlograms of Moran’s I showed significant positive value was about 7 m, but changed into a negative correlation with the increase of distance, indicating strong genetic structure. The natural character of clonal reproduction, restricted seed and pollen dispersal were the main factors of influencing the spatial pattern. The knowledge of clonal structures within populations was crucial for understanding evolutionary processes and ecological adaptation. This study provided basic data for the conservation and management of E. songoricum, especially for sampling strategies for ex situ conservation.

Spatial Genetic Structure of Two HIV-I-resistant Polymorphisms (CCR2-64 Ⅰ and SDF1-3’A) Alleles in Population of Shandong Province, China

To explore the spatial genetic structure of two HIV-Ⅰ-resistant polymorphisms （CCR2-64 Ⅰ and SDF1-3＇A） alleles in the population of Shandong Province, China. Methods Using the techniques of spatial stratified sampling and spatial statistics, the spatial genetic structure of the locus （CCR2-64 Ⅰ and SDF1-3＇A）, which was shown to be important co-receptor for HIV infection, was quantified from the populations of 36 sampled counties of Shandong Province, and a total of 3147 and 3172 samples were taken for testing CCR2-64Ⅰ and SDF1-3＇A respectively from individuals without known history of HIV-Ⅰ infection and AIDS symptoms. Results There were significantly spatial genetic structures of the two alleles at different spatial distance classes on the scale of populations, but on the scale of individuals, no spatial structure was found in either the whole area of Shandong Province or the area of each sampled county. Although the change of frequencies of the two alleles with geographic locations in Shandong Province both showed gradual increase trends, their changing directions were inverse. The frequency of CCR2-64Ⅰallele gradually increased from the southwest to the northeast, while the frequency of SDF1-3＇A allele gradually increased from the northeast to the southwest. However the RH to AIDS of combined types of their different genotypes did not represent obvious geographic diversity on the whole area of the Province. Conclusion The frequency of allele usually has some spatial genetic structures or spatial autocorrelation with different spatial distance classes, but the genotypes of individuals have random distribution in the same geographic area. Evaluating spatial distribution of the genetic susceptibility of HIV （AIDS） to CCR2-64Ⅰand SDF1-3＇A alleles, should focus on the frequencies of combined genotypes of CCR2 and SDFI based on the two-locus genotypes of each individual rather than the frequencies of CCR2-641 and SDF1-3＇A alleles.

Spatial Autocorrelation Analysis of Genetic Structure of Zelkova schneideriana in Mailing Town,Guangxi

We analyzed the fine-scale spatial genetic structure of the individuals of Zelkova schneideriana , which were classified by age using the spatial autocorrelation method, to quantify spatial patterns of genetic variation within the population and to explore potential mechanisms that determine genetic variation in population. The spatial autocorrelation coefficient （ r ） at 13 distance classes was determined on the basis of both geographical distance and genetic distance matrix which was derived from co-dominant SSR data using GenAlEx software. The results showed that all the individuals of Z. schneideriana exhibited significantly positive spatial genetic structure at distance less than 40 m （the X -intercept was 53.568）, indicating that the average length of the smallest genetic patch for the same genotype clustering of the Z. schneideriana Mailing population was about 50 m. Limited seed dispersal is the main factor that leads to the spatial genetic variation within populations. The individuals in age Class II showed significantly positive spatial genetic structure at distance less than 30 m （the X -intercept was 47.882）, while the individuals in age Class I and age Class III showed no significant spatial genetic structure in any of the spatial distance classes. Z. schneideriana is a long-lived perennial plant; the self-thinning resulted from the cohort competition between individuals in the growing process may lead to this certain spatial structure in age Class III of Z. schneideriana population.

Genetic diversity and structure of Drimys brasiliensis in southern Brazil:insights for conservation

Population genetics studies are widely recognized for generating useful knowledge for biodiversity conservation.To date,however,little is known about the levels and distribution of genetic diversity of Drymis brasiliensis(Miers LC),a tree species from the Atlantic Rainforest.Therefore,in this study,we investigated how genetic diversity is distributed within and among populations of D.brasiliensis from southern Brazil using allozyme markers to genotype reproductive trees(8 populations)and seedlings(3 populations).Furthermore,in two populations,we established two permanent plots(5.1 and 1 ha)to analyze fine-scale genetic structure(FSGS).Studied populations presented low levels of genetic diversity(reproductive=0.085;seedlings=0.054)and high fixation indexes(reproductive=0.396;seedlings=0.231).Genetic divergence among populations was equal to 0.05,which is significant,signaling that few populations can conserve large portions of the species total genetic diversity.FSGS was only detected for one population,when reproductive individuals were separated by less than40 m.Low genetic diversity combined with high fixation indexes clearly signal a risk of losing diversity.Therefore,conservation efforts should be aimed at enhancing gene flow within the studied populations.

Mapping the Genetic Diversity of Castanea sativa: Exploiting Spatial Analysis for Biogeography and Conservation Studies

The current distribution of forest tree species is a result of natural or human mediated historical and contemporary processes. Knowledge of the spatial distribution of the diversity and divergence of populations is crucial for managing and conserving genetic resources in forest tree species. By combining tools from population genetics, landscape ecology and spatial statistics, landscape genetics thus represents a powerful method for evaluating the geographic patterns of genetic resources at the population level. In this study, we explore the possibility of combining genetic diversity data, spatial statistic tools and GIS technologies to map the genetic divergence and diversity of 31 Castanea sativa populations collected in Spain, Italy, Greece, and Turkey. The IDW technique was used to interpolate the diversity values and divergence indices as expected hetereozygosity (He), allelic richness (Rs), private allelic richness (PRs), and membership values (Q) of each population to different clusters. Genetic diversity maps and a synthetic map of the spatial genetic structure of European chestnut populations were produced. Spatial coincidences between landscape elements and statistically significant genetic discontinuities between populations were investigated. Evidence is provided of the significance of cartographic outputs produced in the study and on their usefulness in managing genetic resources.

Assessment of Genetic Diversity of Moroccan Cultivated Almond(Prunus dulcis Mill.DA Webb)in Its Area of Extreme Diffusion,Using Nuclear Microsatellites

Assessment of genetic diversity of Moroccan cultivated almond (Prunus dulcis Mill.) grown from seed and cultivated at four eco-geographical regions was performed using 16 nuclear SSRs. 238 alleles were detected with an average of 14.88 alleles per locus, ranging from 4 (locus BPPCT027) to 24 (locus CPSCT018). The size of alleles ranged from 84 bp (locus UDP96-003) to 253 bp (locus UDP96-018). A high genetic diversity of the local almonds is apparent and structured into three major clusters (Oasis cluster, High and Anti Atlas cluster, and Middle Atlas cluster). Compared to the Mediterranean genetic pools, from the East to West, the genetic diversity tends to be limited in Morocco which is the area of its extreme diffusion.

Genetic diversity of Mansonia altissima A. Chev. under different regimes of human impact in the Akure Forest Reserve,Nigeria

Mansonia altissima is an important West African timber tree species. For the purpose of examining the effect of human impact on its genetic diversity, genetic diversity and spatial genetic structure of the species under different regimes of human impact were investigated in the Akure Forest Reserve, Nigeria, using 504 amplified fragment length polymorphism （AFLP） markers. The results indicate a very low genetic diversity in M. altissima within the forest reserve （He = 0.045; PPL = 16.75%; Br = 1.162）. The highest genetic diversity was observed in the primary forest （H e= 0.062; PPL - 21.00%; Br = 1.204）, with the lowest genetic diversity in the isolated forest patch （He = 0.032; PPL = 9.00%; B r= 1.089）. A significant and pronounced spatial genetic structure was found in the logged forest and in the isolated forest patch. In contrast, the primary forest exhibited very weak spatial genetic structuring. As expected, no spatial genetic structure was found in the planted stands of M. altissima. From a conservation point of view, our results suggest that genetic diversity ofM. altissima is at risk in the forest reserve. The scale of human impact in the study area could pose a serious threat to the maintenance of genetic diversity of the species. These results would offer practical applications in the conservation of other tropical tree species.

Population Genetic Structure of the Medicinal Plant Vitex rotundifolia in China: Implications for its Use and Conservation

Vitex rotundifolia L. is an important plant species used in traditional Chinese medicine. For its efficient use and conservation, genetic diversity and clonal variation of V. rotundifolia populations in China were investigated using inter-simple sequence repeat markers. Fourteen natural populations were included to estimate genetic diversity, and a large population with 135 individuals was used to analyze clonal variation and fine-scale spatial genetic structure. The overall genetic diversity （GD） of V. rotundifolia populations in China was moderate （GD=0.190）, with about 40% within-population variation. Across all populations surveyed, the average within-population diversity was moderate （P = 22.6%; GD = 0.086）. A relatively high genetic differentiation （Gst = 0.587） among populations was detected based on the analysis of molecular variance data. Such characteristics of V. rotundifofia are likely attributed to its sexual/asexual reproduction and limited gene flow. The genotypic diversity （D = 0.992） was greater than the average values of a clonal plant, indicating its significant reproduction through seedlings. Spatial autocorrelation analysis showed a clear within-population structure with gene clusters of approximately 20 m. Genetic diversity patterns of V. rotundifolia in China provide a useful guide for its efficient use and conservation by selecting particular populations displaying greater variation that may contain required medicinal compounds, and by sampling individuals in a population at 〉20 m spatial intervals to avoid collecting individuals with identical or similar genotypes.

Species diversity and population density affect genetic structure and gene dispersal in a subtropical understory shrub

Aims The dispersal of pollen and seeds is spatially restricted and may vary among plant populations because of varying biotic interactions,population histories or abiotic conditions.Because gene dispersal is spatially restricted,it will eventually result in the development of spatial genetic structure(SGS),which in turn can allow insights into gene dispersal processes.Here,we assessed the effect of habitat characteristics like population density and community structure on small-scale SGS and estimate historical gene dispersal at different spatial scales.Methods In a set of 12 populations of the subtropical understory shrub Ardisia crenata,we assessed genetic variation at 7 microsatellite loci within and among populations.We investigated small-scale genetic structure with spatial genetic autocorrelation statistics and heterogeneity tests and estimated gene dispersal distances based on population differentiation and on within-population SGS.SGS was related to habitat characteristics by multiple regression.Important Findings The populations showed high genetic diversity(He=0.64)within populations and rather strong genetic differentiation(F#ST=0.208)among populations,following an isolation-by-distance pattern,which suggests that populations are in gene flow–drift equilibrium.Significant SGS was present within populations(mean Sp=0.027).Population density and species diversity had a joint effect on SGS with low population density and high species diversity leading to stronger small-scale SGS.Estimates of historical gene dispersal from between-population differentiation and from within-population SGS resulted in similar values between 4.8 and 22.9 m.The results indicate that local-ranged pollen dispersal and inefficient long-distance seed dispersal,both affected by population density and species diversity,contributed to the genetic population structure of the species.We suggest that SGS in shrubs is more similar to that of herbs than to trees and that in communities with high species diversity gene flow is more restricted than at low species diversity.This may represent a process that retards the development of a positive species diversity–genetic diversity relationship.

Subpopulation genetic structure of a plant panmictic population of Castanea sequinii as revealed by microsatellite markers

Castanea squinii Dode,an endemic tree widely distributed in China,plays an important role both in chestnut breeding and forest ecosystem function.The spatial genetic structure within and among populations is an important part of the evolutionary and ecological genetic dynamics of natural populations,and can provide insights into effective conservation of genetic resources.In the present study,the spatial genetic structure of a panmictic natural population of C.sequinii in the Dabie Mountain region was investigated using microsatellite markers.Nine prescreened microsatellite loci generated 29-33 alleles each,and were used for spatial autocorrelation analysis.Based on Moran’s I coefficient,a panmictic population of C.sequinii in the Dabie Mountain region was found to be lacking a spatial genetic structure.These results suggest that a high pollen-mediated gene flow among subpopulations counteract genetic drift and/or genetic differentiation and plays an important role in maintaining a random and panmictic population structure in C.sequinii populations.Further,a spatial genetic structure was detected in each subpopulation’s scale(0.228 km),with all three subpopulations showing significant fine-scale structure.The genetic variation was found to be nonrandomly distributed within 61 m in each subpopulation(Moran’s I positive values).Although Moran’s I values varied among the different subpopulations,Moran’s I in all the three subpopulations reached the expected values with an increase in distances,suggesting a generally patchy distribution in the subpopula-tions.The fine-scale structure seems to reflect restricted seed dispersal and microenvironment selection in C.sequinii.These results have important implications for understanding the evolutionary history and ecological process of the natural population of C.sequinii and provide baseline data for formulating a conservation strategy of Castanea species.

Prominent genetic structure across native and introduced ranges of Pluchea indica, a mangrove associate, as revealed by microsatellite markers

Aims Pluchea indica is a mangrove-associate species,known for its medicinal properties in its native range and being invasive in part of its introduced range.This study aimed to assess geographic distribution of genetic variation of this species across its distribution range,identify the factors influencing its genetic structure and use this information to suggest conservation and management strategies in its native and introduced ranges,respectively.Methods We assessed the genetic diversity and population structure of 348 individuals from 31 populations across its native(Asia)and introduced(USA)ranges for 15 nuclear microsatellite loci.The spatial pattern of genetic variation was investigated at both large and regional spatial scales with the hypothesis that geographic distance and natural geographic barriers would influence the population structure with varying levels of differentiation across spatial scales.Important Findings We found relatively high genetic diversity at the population level and pronounced genetic differentiation in P.indica,as compared with the genetic diversity parameters of mangroves and mangrove associates in this region.Most of the populations showed heterozygote deficiency,primarily due to inbreeding and impediment of gene flow.Analysis of population structures at large spatial scale revealed the presence of two major clusters across the species’natural range separating populations in China from those in Indonesia,Malaysia,Singapore,Thailand,Cambodia and Philippines,and that the USA population might have been introduced from the population cluster in China.Genetic differentiation between populations was also observed at the regional scale.A large number of populations showed evidence of genetic bottleneck,thereby emphasizing the risk of local extinction.Based on these findings,our study recommends in situ conservation strategies,such as to prioritize populations for conservation actions and to maintain genetic diversity.

辽宁爪鲵种群的空间遗传结构

利用13个微卫星位点对4个地理种群的辽宁爪鲵(Onychodactylus zhaoermii)进行遗传多样性及空间遗传结构研究,结果表明:230个样本中共检测到69个等位基因,各种群的差异等位基因数(Na)为1.538~4.462,遗传多样性较低。除本溪县新开村种群(PopⅣ)外,岫岩县华山村(PopⅠ)种群、辽阳县鸡爪村(PopⅡ)种群、辽阳县韩家村(PopⅢ)种群间无显著遗传分化,遗传变异主要来源于种群内部。在以水系划分种群时,表现出一定的遗传差异。在采样位点直线距离小于500 m时,辽宁爪鲵个体间具有较高的遗传相似性。4个种群之间存在3个屏障,结合地理因素,PopⅣ与其他3个种群之间形成了显著的地理阻隔,建议将各地理种群确立为一个管理单元,加强栖息地保护,减少生境片段化对辽宁爪鲵野生资源的影响。

基于云计算的蛋白质折叠空间结构预测

构建基于云计算的蛋白质折叠空间结构预测框架,通过数据云存储设备获取蛋白质序列原始数据,采用HDFS(Hadoop Distributed File System)分布式存储方式保存于云端。资源和队列管理器RQM(Resource Queue Man‐agement)开启云端虚拟机后,以之作为扫描节点(Sensor Node,SN),SN基于二维AB非格点模型建立最小蛋白质分子能量优化函数,采用局部搜索机制改进的量子遗传算法对其作优化求解。利用云端GPU设备处理模型训练数据,即可实现蛋白质折叠空间结构的自动化预测。实验结果表明:蛋白质序列能量势函数计算结果更小、执行效率更高、GDT-TS(Geothermal Development and Testing Tool Suite)评价指标值更大。

Patterns of grassland invasions by trees: insights from demographic and genetic spatial analyses

Aims Woody invasions into grasslands have increased globally due to changing land use,climate and introduced woody species,but spatial processes generating and sustaining these invasions are not well understood.To gain insight into the patterns of spread of tree populations within grasslands,and to propose a full spatial analytical toolbox for studying native and non-native woody spe-cies spread when long-term data are not available,we tested if 50 years of grassland invasion in Western Carpathians by Norway spruce(Picea abies Karst.)proceeded by one of the two tradi-tionally competing hypotheses of species spread:(i)by frontier expansion,or(ii)by advanced groups established ahead of the population frontier.We also tested whether the pattern of invasion changed over time.Methods We analyzed the spatial demographic and genetic patterns of a Norway spruce population invading a Western Carpathian grass-land using ripley’s L(t)and genetic kinship coefficients(Fij).We mapped and genotyped spruce trees across the invasion front(from the invasion leading edge to fully colonized grassland near the source population)using three demographic classes(adults,juve-niles and seedlings)to approximate the temporal aspects of the invasion.We studied how the spatial patterns of invasion by indi-vidual demographic classes and their genetic kinship varied among adjacent plots established at different distances from the source population(ranging from 0 to 160 m,in 40-m distance increments).Important Findings Juveniles were positively genetically related to adults on fine scales(<4 m),suggesting that adults within the grassland acted as a seed source and accelerated early invasion.However,adults did not act as nucleation centers for the formation of advanced juvenile groups.Instead,geneti-cally unrelated juveniles formed groups independently of adults.These groups were small and separate at the leading edge but they increased in size and graded into a continuous zone near the source population.Thus,juvenile recruitment occurred as a frontier expansion near the source population and as advanced groups controlled by environmental variation at the leading edge.unlike juveniles,seedlings were clustered on all scales across the invasion front and formed groups around adult crowns at the invasion leading edge.The bulk of seedling establishment occurred at intermediate distances from the source population,indepen-dently from the adults,suggesting that the invasion front continued to expand as a frontier,gradually coalescing with the advanced groups at the leading edge.Thus,the grassland invasion was driven by a gradual frontier expansion of the original population during the first 50 years,with advanced groups enhancing but not driving the invasion process.Frontier expansion appeared more important as a mechanism of woody species spread early in the invasion process in this study,while advanced groups may play a larger role over longer temporal scales.

基于空间自相关分析研究毛红椿天然居群的空间遗传结构

利用8对微卫星标记对分布于我国的3个毛红椿天然居群的遗传结构进行研究。收集毛红椿3个天然居群209个单株材料并对每个单株的位置进行定位,运用空间自相关分析研究毛红椿居群的空间遗传结构,了解该物种的进化历程和濒危机制,并为制定有效的保护策略和措施提供科学依据。研究结果表明：1）居群等位基因的平均数为5.3,有效等位基因数平均为2.6;2）观察杂合度平均为0.5990,期望杂合度平均为0.5893;3）空间自相关分析结果揭示毛红椿宜丰天然居群在0～240m存在着显著的空间遗传结构;4）宾川和师宗居群内遗传变异在空间上为随机分布,不存在明显的空间遗传结构;5）导致居群内空间遗传结构形成的原因,包括花粉种子局限传播、微环境异质性和居群密度等。

猕猴桃自然居群SSR遗传变异的空间自相关分析

本研究采用空间自相关分析方法对同域分布的中华猕猴桃(Actinidiachinensis)和美味猕猴桃(A.deliciosa)自然居群SSR遗传变异的空间结构进行了研究,以探讨猕猴桃自然居群遗传变异的分布特征。选用的9对SSR引物在两物种中共扩增出104个等位基因。选择频率在20–80%的SSR等位基因,运用等样本对频率方法分别对同域分布的中华猕猴桃和美味猕猴桃各1个居群及其中华/美味猕猴桃复合居群进行了空间自相关系数Moran’sI值计算。结果表明:中华猕猴桃和美味猕猴桃的遗传变异在居群内均存在着一定程度的空间结构,尽管近半数或半数以上的等位基因在居群内表现为随机分布的空间模式,但也有相当比例(29.6–48.0%)的等位基因在种内居群中和复合居群中(河南西峡51.0%,陕西商南44.7%)呈现渐变、衰退、双向衰退或侵扰模式。而且其居群内遗传变异的空间分布规律,不论是在种内还是复合居群中都基本一致:相距在100m以内,特别是30m范围内的个体间的等位基因表现出显著性的正相关,但随着地理距离的增大逐渐显示出负相关,说明猕猴桃属植物的有效传粉距离可能在100m左右,种子散播主要集中在30m的近距离内。猕猴桃自然居群遗传变异的空间结构是其传粉和种子散播等生物学特性与生境共同作用的结果,其中种子近距离的散播、花粉传播的有限距离及人为干扰是最主要的因素。本研究结果揭示了这两个近缘物种居群遗传变异的空间分布特征及相互关系,有助于进一步探讨猕猴桃属植物的遗传变异、居群扩散及其地理系统发育进化等方面的规律,并为制定相应的保育策略和措施提供基础数据和科学依据。

水杉孑遗居群AFLP遗传变异的空间分布

本研究采用空间自相关分析方法对水杉 (Metasequoiaglyptostroboides)孑遗居群AFLP遗传变异的空间结构进行了研究 ,以探讨水杉孑遗居群遗传变异的分布特征及其形成机制。根据 6对AFLP选择性引物扩增的 46个多态性位点 ,选择了其表型频率在 2 5 %～ 75 %的 2 7个AFLP标记 ,运用等样本频率方法和等地理距离间隔方法分别对 3 9株和 3 7株原生母树进行了空间自相关系数Moran’sI值计算。结果表明 :水杉孑遗居群缺乏空间结构 ,绝大多数AFLP位点变异为随机分布的空间模式 ,但也有少数位点存在显著性随机相关 ,在 4～ 8km地理距离间隔显示负相关 ,说明该间隔可能是水杉孑遗居群的部分基因交流的有效屏障。水杉原生母树分布存在 12～ 2 8km的明显距离间隔空挡 ,说明人类从迁入该区域起就影响着水杉孑遗居群的原始生境 ,导致其生境片断化、景观破碎 ,进而形成岛屿状分布格局 ,并引起了水杉残留居群的随机遗传漂变。根据本研究结果 ,结合水杉孑遗居群较低的遗传多样性 ,分析探讨了水杉孑遗居群濒危的机理 ,并提出了相应的保育策略 。

日本血吸虫中间宿主湖北钉螺遗传变异的空间相关分析

目的探讨湖北钉螺的空间遗传结构。方法采用扩增片段长度多态性(AFLP)分子标记技术对10省或自治区(云南、四川、广西、福建、湖南、湖北、江西、安徽、江苏和浙江)25个钉螺种群基因组DNA进行扩增,分析钉螺种群间的遗传距离与地理距离的相关性。结果25个钉螺种群间的遗传距离D和Nei无偏遗传距离,都与其地理距离存在明显的正相关性(P<0.001),相关系数分别为0.5234和0.5622;湖北钉螺指名亚种种群间的遗传距离与地理距离也存在正相关(P<0.001),遗传距离D的相关系数为0.5276,Nei无偏遗传距离的为0.5770;无论是肋壳钉螺还是光壳钉螺,钉螺种群间的遗传距离都与地理距离存在正相关(P<0.001),肋壳钉螺种群间的遗传距离D和Nei无偏遗传距离与地理距离的相关系数分别为0.3612和0.3916,光壳钉螺的相关系数分别为0.7535和0.7500。结论在我国大陆广泛分布的湖北钉螺种群间具有明显的空间遗传结构。