Genetic variation among 11 <Emphasis Type="Italic">Abies concolor</Emphasis> populations based on allozyme analysis

In order to obtain information on the genetic structure ofAbies concolor and the genetic variation among 11 populations introduced from America to China, allozyme analysis based on starch gel electrophoresis technology was used. 24 loci of 10 allozyme systems were mensurated, and the genetic structure and genetic diversity of the 11 populations of A. concolor evaluated. The results show that the genetic variation among is significant, and the genetic variation within A. concolor populations is more important. In contrast with other conifers, the variation of A. concolor is above the average level of conifers, and higher than the same level of Abies. The percentage of polymorphic loci (P) was 62.5%, the number of alleles per locus (A) 2.08, the number of effective alleles per locus (Ae) was 1.37, the expected heterozygosity (H) 0.204, and the Shannon information index (/) 0.351 7. There is a short genetic distance (D=0.061) and a low gene flow (Nm=0.839 4) among the 11 introduced populations ofA. concolor with high genetic variation. The genetic differentiation coefficient (Gst) was 0.229 5, which is higher than that of the mean in Abies or Pinus.     

Effect of Regeneration Method on RAPD-Based Genetic Variation of Cyclobalanopsis glauca (Fagaceae)

Cyclobalanopsis glauca is a dominant species of evergreen broad-leaved forests in mainland China. This study compares the genetic variation of an artificially regenerated population with its donor population and two other wild populations, by using RAPD markers. A total of 74 clear, reproducible bands were scored for 12 RAPD primers; 72 were polymorphic (P = 97.3%). AMOVA revealed that most genetic variation was within populations and only 10.35% was among populations. Various measures indicated that there is no difference in genetic diversity between the planted and the original populations. Φ_ST between the planted offspring population and the donor population was larger than those between the planted and other two natural populations, indicating that artificial regeneration might lead to biased genetic composition, given that temporal differentiation is usually lower than spatial differentiation. This divergence may be due to unequal seed production among the maternal individuals and viability differences among seeds.     

无患子天然居群遗传多样性研究

[目的]通过我国无患子主要分布区的居群样本,研究无患子天然居群的遗传多样性和遗传结构.[方法]采用ISSR分子标记技术,利用12条ISSR引物分析18个天然居群的265株个体样本.[结果]表明无患子遗传多样性水平较高,物种和居群水平上的多态位点百分率 (PPB)分别为95.37%和57.82%,Shannon's信息指数(I)分别为0.256 9和0.199 8,Nei's遗传多样性指数(H)分别为0.390 9和0.298 0.AMOVA分析表明,18个居群间出现一定程度的遗传分化,且遗传变异主要发生在居群内.UPGMA聚类和Mantel检验结果表明,18个天然居群可分为2大组群,且居群间的地理距离与遗传距离之间不存在显著相关性(r=0.066 7,P=0.541 7>0.05).[结论]无患子以自交为主,其天然居群遗传多样性丰富,居群内的遗传多样性高于居群间.研究结果可为无患子育种策略的科学制定和种质资源的有效保护及利用提供理论依据.     

花吊丝竹居群遗传多样性的ISSR分析

[目的]研究花吊丝竹居群遗传多样性和遗传结构,为种质资源有效利用和良种选育提供理论指导。[方法]利用12条ISSR引物对48份种质(共3个居群)花吊丝竹居群进行遗传多样性和遗传距离分析。[结果]共检测到124个位点,其中,多态性位点为102个,种质和居群水平上的多态位点百分比(PPB)分别为82. 26%和50. 27%,Ne’基因多样性指数(He)分别为0. 220 4和0. 206 6,Shannon’s信息指数(I)分别为0. 349 4和0. 300 5,表明花吊丝竹居群间存在中等水平的遗传变异。根据Nei’s遗传多样性计算出不同居群间分化水平(Gst)=0. 163 3,表明16. 33%的遗传变异存在于居群间,居群内的遗传变异为83. 67%。居群间的基因流Nm为2. 562 1,表明花吊丝竹居群间存在较大基因流,很大程度减少居群间遗传差异。基于遗传距离的UPGMA聚类结果表明,48份种质可分为3组,3个居群可分为2组,居群间地理距离与亲缘关系无显著相关性。[结论]虽然花吊丝竹主要靠营养生殖来繁衍后代,其居群遗传多样性较丰富,且居群内遗传多样性大于居群间。此外,福建居群遗传多样性明显高于广西和广东地区居群。     

Genetic structure of the green oak leaf roller (Tortrix viridana L.) and one of its hosts, Quercus robur L.

An herbivorous insect, the green oak leaf roller (Tortrix viridana) and one of its host species, pedunculate oak (Quercus robur), were investigated for their genetic variation within and among populations on the basis of mitochondrial, chloroplast, and anonymous markers. Oaks and green oak leaf rollers from 10 oak stands in North Rhine-Westphalia (North-Western Germany) were examined. The genetic variation of pedunculate oaks is much lower within than among populations when assessed using chloroplast gene markers and higher among populations when assessed using anonymous markers. When using mitochondrial and AFLP markers, the genetic variation of the green oak leaf roller populations was higher within than among the populations, which suggests a high gene flow between the populations. Mantel tests on the gene diversities of oaks and the green oak leaf roller yielded a significant negative correlation for both marker types. To sum up, the reasons for the differences in the spatial patterns of the genetic variation of the host and herbivorous insect may be found in their different generation times, mechanisms and capacities for dispersal.The results for the green oak leaf roller revealed a higher migration rate than assumed before which has consequences for the prediction of the dynamics of future outbreak events.     

Assessment of morphological and genetic diversity in <Emphasis Type="Italic">Gmelina arborea</Emphasis> Roxb.

Gmelina arborea is an important timber-yielding tree that grows naturally in the tropical and subtropical regions of Southeast Asia and has also been introduced as a plantation species outside these regions. Genetic diversity in this tree species was observed in stone/seed-related traits and in vitro responses of cultured nodal segments from plants of eight different populations representing natural forests, fragmented forests and plantations. Variance analysis showed significant differences between populations for these traits. However, it was not possible to separate the different populations using these traits by multivariate analysis, even after environmental variation was reduced over six subcultures. Genetic diversity was therefore analysed using molecular markers. Inter-simple sequence repeat (ISSR) primers yielded 95% polymorphic loci among the eight populations and UPGMA analysis enabled separation of these populations on the basis of their genetic distances. Diversity was also analyzed using population genetics parameters like Nei’s genetic diversity and gene differentiation. Nei’s genetic diversity was 0.29 between populations and 0.11 within populations. AMOVA analysis indicated 41 and 59% within- and between-population genetic diversity, respectively. Mantel test suggested that genetic differentiation between six Indian populations was positively correlated to geographic distance (r = 0.626, P = 0.029). Assessment of the genetic variation in G. arborea populations is an important step in selection of conservation strategies for this species since diversity forms the basis for species adaptation.     

Genetic analysis and conservation of endangered medicinal tree species <Emphasis Type="Italic">Taxus wallichiana</Emphasis> in the Himalayan region

Taxus wallichiana is one of the most important medicinal tree species of the Himalayan region. Leaf and bark of the species yield an important drug called taxol, which is used for treatment of many types of cancer. There is a serious threat to the existence of the species due to over exploitation in its native habitat. Adequate information on the nature and the extent of genetic diversity in this important species is required for developing suitable strategy for its conservation. Random amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) were used to assess genetic variation in nine natural populations of T. wallichiana from western part of the Himalayan ranges. Both the markers revealed low genetic diversity in these populations. Average heterozygosity for AFLP and RAPD were 0.3715 and 0.3072, respectively. Φ_ST values derived from molecular variance were 0.0855 and 0.1005 for AFLP and RAPD, respectively, whereas the corresponding G_ST values were 0.1796 and 0.2140. Most part of the genetic variation was present within the populations. However, between population variation was low but statistically significant, which suggested that the sampled populations might not constitute a single panmictic population. Cluster analysis and Mantel’s correlation revealed that genetic differentiation broadly followed geographic distribution of the populations. T. wallichiana thus urgently needs to be conserved using both in situ and ex situ conservation approaches.     

Genetic diversity and differentiation of fall webworm (Hyphantria cunea Drury) populations

The molecular variation and genetic relationships among five populations of the fall webworm (Hyphantria cunea Drury) in China were assessed using microsatellite technology. Ten microsatellite primers, producing polymorphic bands, were used across 300 samples. The percentage of polymorphic loci (PPB) was 98.36%; the percentage of polymorphic loci in five populations ranged from high to low in the following order: Cangzhou population, Yantai population, Qinhuangdao population, Dandong population, and Shijiazhuang population. The results showed that 34.38% of the total genetic variation of the fall webworm (GST) occurs among populations, while most variation (65.62%) exists within populations. Nei’s genetic distances ranged from 0.1386 to 0.3224. Using the unweighted pair group method with arithmetic mean (UPGMA), Nei’s genetic distances were analyzed by a clustering technique and the dendrogram shows that population differentiation is closely related to the time and geographic origin of the invasion. The major factors impacting genetic diversity of fall webworm populations are longitude, the plain area ratio, annual precipitation, latitude and time of invasion. The formation of genetic structure is correlated with characteristics of the life history and invasion ecology of the species.     

毛红椿天然群体遗传多样性及取样策略探讨

[目的]研究毛红椿天然群体遗传多样性取样策略,为其种质资源收集、保存和遗传多样性保护等提供参考依据。[方法]利用8对微卫星分子标记进行毛红椿天然群体遗传多样性和空间自相关分析,综合制定其天然群体合理取样策略。[结果]毛红椿天然群体等位基因数平均为7.5个,期望杂合度(H_e)和多态性信息指数(PIC)均值分别为0.643 7和0.636 0,基因分化系数(G_(ST))均值为0.290 7。在遗传多样性取样策略方面,提出了根据毛红椿群体基因分化系数来确定取样群体遗传变异所占总变异比例的运算公式为1-(G_(ST))~(n-1),其中,n为取样群体的数量。当取样群体达到4个时,基本上能包括该树种97.5%的遗传变异;同时确定了目标群体的选择方法,应选择与其它群体间基因分化系数均值较大的4个群体,即贵州册亨(CH)、浙江遂昌(SC)、浙江仙居(XJ)和云南师宗(SZ)。通过构建云南宾川(BC)、云南师宗(SZ)和江西宜丰(YF)群体内取样单株数量与基因多样性和等位基因之间的捕获曲线,确定了群体内取样单株数量应达到15个以上;毛红椿天然群体内300～520 m范围内的单株间存在相似关系,超出此范围个体间差别较大,说明在进行群体内单株取样时,单株间距应大于520 m。[结论]取样群体数量、群体间遗传分化系数、群体内单株数量以及单株间距离等影响了毛红椿取样群体的遗传多样性。毛红椿天然群体遗传多样性取样策略为取样群体4个、每个群体最少取样15个单株,单株间距大于520 m。     

Genetic Diversity of RAPD Mark for Natural Davidia involucrata Populations

The genetic diversity and genetic variation within and among populations of five natural Davidia involucrata populations were studied from 13 primers based on random amplified polymorphic DNA (RAPD) analysis. The results show that natural D. involucrata population has a rich genetic diversity, and the differences among populations are significant. Twenty-six percent of genetic variation exists among D. involucrata populations, which is similar to that of the endangered tree species Liriodendron chinense and Cathaya argyrophylla in China, but different from more widely distributed tree species. The analysis of the impacts of sampling method on genetic diversity parameters shows that the number of sampled individuals has little effect on the effective number of alleles and genetic diversity, but has a marked effect on the genetic differentiation among populations and gene flows. This study divides the provenances of D. involucrata into two parts, namely, a southeast and a northwest provenance. Translated from Scientia Silvae Sinicae, 2004, 40(4) (in Chinese)     

Genetic variation ofAlnus trabeculosa populations in Japan

Alnus trabeculosa Hand.-Mazz. is classed as “near threatened,” and efforts should be made to conserve the species, but effective action would require understanding of its genetic variation and structure. Therefore, the genetic variation at 12 isozyme loci was examined in seven populations of the species in Japan. The expected heterozygosity within species (H _es=0.222) and the expected heterozygosity within populations (H _ep=0.199) were found to be slightly higher than in most other woody species. The coefficient of genetic differentiation (G _ST=0.146) was also high. The northernmost population had the lowest values for almost all measures of genetic variation, and populations in southern Japan tended to show greater within-population variation than those in northern Japan. The level and distribution of genetic variation in this species might be related to its life history and ecological traits, and distribution history.     

Spatial genetic structure in populations of the green oak leaf roller, Tortrix viridana L. (Lepidoptera, Tortricidae)

The green oak leaf roller (Tortrix viridana L.) is a major pest on oaks. The green oak leaf roller is one reason within a disease complex for the oak decline, and it leads to defoliation of oaks in spring. In Germany, Quercus robur L. is mainly affected. The partitioning of genetic variation within and among populations of forest pests is linked to their capacities for migration. And the capacity for migration is the basis for dispersal of the pest species to different host trees and host populations and, therefore, for further outbreak events. Thus, the within population spatial genetic structure (SGS) of T. viridana was investigated based on nuclear (AFLP) markers to analyse the dispersal capacity of this insect pest species at a very small spatial scale. A total of 401 individuals of the green oak leaf roller from four stands in North Rhine-Westphalia (Western Germany) were examined. In three of four populations, the AFLP markers revealed clearly SGS up to 40 m, which can be explained by the mating behaviour within this species.     

Genetic diversity of Betula luminifera populations at different elevations in Wuyi Mountain and its association with ecological factors

The random amplified polymorphic DNA (RAPD) technique was used to evaluate the genetic diversity and population structure of 91 genets from four wild populations of Betula luminifera at different elevations in the National Nature Reserve of theWuyi Mountain, Fujian Province, China. Eighteen random primers (from 139 primers) produced a total of 199 scorable amplified fragments, of which 174 (87.44%) were polymorphic across all individuals. The genetic diversities of B. luminifera at the population level and species level were PPL = 60.05%, h = 0.2242, I = 0.3181 and PPL = 87.44%, h = 0.3442, I = 0.4899, respectively. The value of differentiation (G _st= 0.3486) and analysis of molecular variance (AMOVA) indicated that there was a relatively high genetic differentiation among populations, and about one-third of the genetic variation occurred among populations. Pearson correlation analysis further revealed that the genetic diversity within populations had significant or very significant correlation with the elevation, climatic factors (annual average temperature and annual precipitation) and soil nutrient factors (total nitrogen, C/N ratio and organic matter). Mantel tests show that there was a significant correlation between the genetic distances among populations and the distance of elevation, and the divergence of soil nutrient factors. The results of the present study suggested that the relatively high genetic differentiation among populations of B. luminifera at different elevations might be caused by ecological factors and gene flow. __________ Translated from Scientia Silvae Sinicae, 2008, 44(3): 50–55 [译自: 林业科学]     

Genetic variation and division of Pinus sylvestris provenances by ISSR markers

Inter Simple Sequence Repeat (ISSR) was used to detect genetic variation among nine provenances, including 135 individuals. A total of 108 loci were amplified using 10 random primers. The differentiation of the percentage of polymorphic bands (PPB) among different provenances was evident, ranging from 27% to 54%, of which Honghuaerji provenance had the highest PPB and Kalunshan provenance had the lowest PPB. Shannon's Information index (I) at species level was 0.1581 and Nei's gene diversity (h) was 0.2393. Coefficient of gene differentiation (G_ST) calculated by Popgene was 0.3965, these results indicated that majority of genetic variation (60.35%) was found within provenances. According to dendrogram amongpinus sylvestriv provenances, nine provenances were divided into two provenance areas, namely Daxing's and Xiaoxing'an Mountains provenance area and Hulunbeier provenance area. Foundation item: This study was supported by National Scientific and Technological Brainstorm Project. Biography: LI Hui-yu (1978-), female, Ph.D. candidate, Northeast Forestry University, Harbin 150040, P. R. China. Responsible editor: Song Funan     

Small-scale genetic diversity in oneseed hawthorn (<Emphasis Type="Italic">Crataegus monogyna</Emphasis> Jacq.)

We have examined the pattern of random amplified polymorphic DNA (RAPD) variation among six populations of Crataegus monogyna from northern Italy, extending over an area of about 20,000 km². The aim was to evaluate local differentiation in relation to geographical distance. Of the 73 loci analysed, 65 were polymorphic, and there were no bands at complete fixation at the population level. The mean genetic diversity was 0.291, with the values for individual populations ranging between 0.252 and 0.333. According to the analysis of molecular variance most of the genetic variation was found within populations (about 80%), with a significant proportion being attributable to genetic differences between populations. No evidence for isolation by distance was found in the set of populations sampled. The efficacy of RAPD markers in analysing genetic variation, and the contribution of the results in terms of the preservation of biodiversity and defining the most appropriate strategies for collecting forest reproductive material, are discussed.     

云南松主分布区天然群体的遗传多样性及保护单元的构建

以20个云南松天然群体为对象,SSR分析表明云南松遗传变异主要存在于群体内,各群体间的遗传多样性水平差异不显著。基于SSR分子标记遗传多样性分析,根据Nei's遗传相似度,采用逐步聚类优先取样法,分别对初始群体、遗传多样性保护单元和剩余群体进行比较、t检验,以此评价遗传多样性保护单元的代表性。结果表明,利用该方法抽样的群体能很好地代表初始群体的遗传多样性,按30%的群体抽样,等位基因数、有效等位基因数、Shannon's信息指数和期望杂合度的保留率分别达到初始群体的98.03%、105.36%、103.99%和105.56%。保护单元的遗传多样性均高于剩余群体,抽样群体组成的遗传多样性保护单元的效果较好。     

Genetic diversity of Castanopsis acuminatissima (Bl.) A. DC. in northern Thailand and the selection of seed trees for forest restoration

Castanopsis acuminatissima (Bl.) A. DC. is one of a number of framework species which are being planted to restore seasonally dry tropical forests in northern Thailand. This study describes the level of microsatellite variation within and among three populations of this species in three National Parks in northern Thailand: Doi Suthep-Pui, Doi Inthanon and Jae Sawn, using published primers developed for Castanopsis cuspidata var. sieboldii Nakai. The five microsatellite loci employed in this study detected a total of 54 alleles (n = 72). The informativeness of the microsatellite loci varied from six to 18 alleles, with an average of 10.8 alleles found over all loci. The mean observed heterozygosities in the three populations showed no significant deviations from Hardy-Weinberg expectations. The vast majority of genetic diversity was contained within the populations, with no significant differentiation between them (F_ST = 0.006). Algorithms were designed to capture microsatellite diversity, and the rationale for using microsatellite markers to inform genetic conservation is discussed. The implications for seed collection of C. acuminatissima for forest restoration are also discussed.     

An analysis of the pattern of genetic variation in Vitellaria paradoxa using RAPD markers

Vitellaria paradoxa C.F.Gaertn. is one of the most economically and socially important tree species in the Sudano-Sahelian region. Little is known of the pattern of variation within its natural range. Eight populations covering most of the natural range from Senegal to Uganda were sampled and leaves of 118 individual trees were collected. An analysis of molecular diversity was carried out using random amplified polymorphic DNA (RAPD) markers. Fifteen random primers generated 67 polymorphic and 15 monomorphic RAPD loci ranging from size 1670 bp to 280 bp. Shannon's diversity index varied from Central Africa/Ndele (0.374) to Uganda/Amoya (0.350) but the differences between populations were smaller than the population standard errors. Correspondence analysis of unrooted neighbour-joining trees suggested that genetic distances between populations were correlated with geographic distances. This trend was confirmed by a Mantel test giving a coefficient of correlation between genetic and geographic distances of R = 0.88 (P = 0.0001). Result of AMOVA (analyses of molecular variance) showed that 14.8% (P = 0.002) of the RAPD variation was distributed among populations. Nested analysis of variance indicated that variance between the western and eastern groups of population represented 8.7% (P = 0.001) of the total variation and the variation amongst populations within group was 9.5% (P = 0.001). Eighty two percent of the variation was explained by variation amongst individuals within populations. The origin of genetic structure and level of diversity may be explained by the glacial refugia, the biological traits of Vitellaria paradoxa and by the impact of semi-domestication. Based on these results, sampling options of the natural populations are suggested for in or ex situ conservation. For the development of Vitellaria paradoxa breeding population, the sampling should consist of many individual trees selected within a few populations to capture a large proportion of variation.This revised version was published online in November 2005 with corrections to the Cover Date.     

Genetic diversity ofKandelia candel andBruguiera gymnorrhiza in the Southwest Islands, Japan

The genetic diversity of the mangrove tree speciesKandelia candel andBruguiera gymnorrhiza in the Southwest Islands of Japan was investigated. These islands are located at the periphery of the distribution area of the two species, and their populations are relatively small. Allozyme analyses of 17 loci inK. candel and 13 loci inB. gynmorrhiza revealed very little genetic variation in both species. At the species level, the proportion of polymorphic loci was 4.2%, the average effective number of alleles per locus was 1.02, and the average expected heterozygosity was 0.012 inK. candel. The corresponding figures forB. gymnorrhiza were 9.0%, 1.06 and 0.035, respectively. However, the coefficients of genetic differentiation among the populations were high (G _ST=0.165 forK. candel and 0.253 forB. gymnorrhiza). The genetic variation and habitat area ofK. candel on Amami Island is greater than on the islands Okinawa and Iriomote. The genetic variation and habitat area ofB. gymnorrhiza is greater on Iriomote Island than on the islands Okinawa and Amami. The level of genetic variation in both of the species might be related to their population sizes.     

珙桐天然种群遗传多样性的ISSR标记分析

利用ISSR分子标记分析来自11个天然珙桐种群的遗传多样性。从100条引物中筛选出5条引物能扩增出稳定、清晰且具多态性的条带,共扩增出77个条带。其中74个为多态,多态条带百分率(PPB)为96.10%;各种群PPB值为37.66%～63.64%,平均为54.07%。种内Shannon多样性指数(HSP)为0.4849,种群内Shannon多样性指数(HPOP)为0.1886～0.3274,平均为0.2774。这表明珙桐在物种和种群水平上均维持较高的遗传多样性。分子方差分析显示,种群间与种群内遗传变异分别占总遗传变异的46.22%,53.78%,种群间呈高度遗传分化。种群间遗传距离与对应的地理距离呈显著正相关(r=0.546,P<0.01)。UPGMA法聚类分析将11个珙桐种群分为3组。研究结果为珙桐遗传资源保护策略制定提供有价值的种群遗传学信息。