真鲷自然群体和人工繁殖群体的遗传多样性

采用RAPD技术对真鲷野生群体及人工繁殖群体各23个个体进行了DNA多态性检测。实验选取OPK组16个10 bp随机引物用于两群体的遗传多样性分析。在野生群体和人工繁殖群体中分别获得131和123条扩增片段,两群体的多态片段比例分别为62.60%和54.47%,平均杂合度分别为0.4786和0.3633,可见真鲷野生群体及人工繁殖群体的遗传多样性较为丰富,在选择育种和遗传改良方面具有较大的潜力。人工繁殖群体的多态片段比例和平均杂合度都低于野生群体,意味着在生产过程中要采取行之有效的管理保护措施以避免或减少遗传多样性水平的降低,确保真鲷增养殖业的可持续发展。     

湖北星斗山台湾杉居群的遗传多样性研究

采用随机扩增多态性DNA(RAPD)方法对孑遗植物台湾杉分布于湖北星斗山的野生和栽培居群共42个个体进行了遗传多样性分析。从60个随机引物中筛选出13个引物,共扩增出155条清晰谱带,多态位点百分率为72.9%。野生居群和栽培居群的多态位点百分率分别为65.81%和59.35%;Nei’s基因多样性分别为0.2001和0.1911;Shannon’s信息指数分别为0.3120和0.2946。野生居群的遗传多样性高于栽培居群,表明这些原生古树的后代出现了一定程度的遗传衰退。用UPGMA方法对42个单株聚类可知,来自野生群体的个体和来自栽培群体的个体明显地各聚为一类。尽管孑遗物种台湾杉在湖北仅有一个野生群体,且为零星分布,总个体数40多株,但仍保持较高的遗传多样性水平,这说明遗传多样性不是导致其种群濒危的主要原因,导致台湾杉种群濒危的原因可能与台湾杉自然种群及群落所处生境的直接破坏及其本身生物学和生态学特性所导致的自然更新不良有着密切的联系。     

Genetic structure of the endangered plant Neolitsea sericea (Lauraceae) from the Zhoushan archipelago using RAPD markers

BACKGROUND AND AIMS: The Zhoushan archipelago is the largest archipelago in China. It separated from the mainland about 9000 years ago due to rising sea levels and climate change. Because of the long-term influences of human activities, the original forest vegetation on the large islands has been badly damaged and its plant diversity reduced. METHODS: Levels and patterns of genetic diversity in 114 individuals from six natural populations and four cultivated populations of the insular endangered plant Neolitsea sericea (Lauraceae) on the Zhoushan archipelago were assessed using random amplified polymorphic DNA (RAPD) markers. KEY RESULTS: A total of 99 discernible loci were obtained for all populations using ten primers, 50.5 % of which were polymorphic [percentage of polymorphic bands (PPB)=50.5 %]. Despite being a woody, long-lived, perennial, outcrossing and insect-pollinated plant, N. sericea exhibited low levels of genetic variation. The cultivated populations (PPB=18.9 %, HE=0.060, S=0.092) were genetically less diverse than the natural populations (PPB=23.1 %, HE=0.082, S=0.123). Based on analysis of molecular variance, a high degree of among-population differentiation was revealed for both natural (0.387) and cultivated populations (0.598). CONCLUSIONS: Removal of plants from the wild for horticulture purposes has eroded the level of genetic variation of N. sericea. Low levels of genetic diversity and a high degree of population differentiation indicate that management strategies should include conservation of natural habitats occupied by all six wild populations, and sampling of germplasm resources from multiple seed sources.     

Distinction between wild and cultivated enset (Ensete ventricosum) gene pools in Ethiopia using RAPD markers

In southwest Ethiopia, the cultivation area of Ensete ventricosum (enset) overlaps with the natural distribution area of this species. Analyses of genetic diversity were undertaken using RAPD to provide information for conservation strategies as well as evidence of possible gene flow between the different gene pools, which can be of interest for future improvement of cultivated enset. The extent of RAPD variation in wild enset was investigated in 5 populations in the Bonga area (Kefficho administrative region) and 9 cultivated clones. Comparisons were also made with some Musa samples of potential relevance for crop improvement. Nine oligonucleotide primers amplified 72 polymorphic loci. Population differentiation was estimated with the Shannon index (G'(ST)=0.10), Nei's G(ST) (0.12) and AMOVA (Phi(ST)=0.12), and appears to be relatively low when compared with outbreeding, perennial species in general. Cluster analysis (UPGMA) and principal component analysis (PCA) similarly indicated low population differentiation, and also demonstrated that cultivated clones essentially clustered distinctly from wild enset samples, suggesting that the present-day cultivated enset clones have been introduced to domestication from a limited number of wild progenitors. In addition, subsequent gene flow between wild and cultivated enset may have been prohibited by differences between modes of propagation and harvesting time; cultivated enset is propagated vegetatively through sucker production and the plant is generally harvested before maturity or flower set, thereby hindering pollination by wild enset or vice versa. A significant correlation was not found between genetic and geographical distances. The relatively high total RAPD diversity suggests that wild enset populations in the Bonga area harbour genetic variability which could potentially act as a source for useful or rare genes in the improvement of cultivated enset. As expected, E. ventricosum was clearly differentiated from the analysed Musa samples, that clustered in accordance with the present morphology- and molecular marker-based taxonomy of the genus.     

用RAPD和ISSR检测的橡胶树野生种质和栽培品种的遗传多样性

用19个RAPD引物和12个ISSR引物对14份野牛橡胶树种质和我国的37份栽培品种进行了遗传多样性分析。RAPD引物共产生132条带,多态性带占88．6％,相似系数变化范围在0．432—0．947。ISSR引物其产生101条带,多态性带占87．1％,相似系数为0．505—0．941。平均基因杂合度分析表明野生种质比栽培品种具有较高的遗传多样性。根据UPGMA法对51份材料进行聚类分析,结果表明,ISSR分析中所有材料可分为2类：第一类为野生种质,第二类为栽培品种：而RAPD分析中野牛种质和栽培品种不能被分为明显的两人类。虽然ISSR和RAPD的聚类分析结果存在差异,但对两种方法进行的相关分析表明,他们之间仍存在极显著相关性,相关系数为0．574。品种PR107、热研217等一些栽培品种可以通过特异带在51份供试材料中被区分开。这些结果可以对橡胶树的育种上作起到一定的指导作用,同时RAPD和ISSR技术也是进行橡胶树品种鉴定和遗传多样性研究的有效手段。     

斑节对虾两个野生亲虾种群遗传多样性

采用RAPD和mtDNA 16S rRNA基因序列分析方法对海南和马来西亚斑节对虾(Penaeus monodon)种群进行了遗传多样性和遗传分化研究.结果表明:15个RAPD随机引物共检测到82个位点,海南和马来西亚种群的多态位点比例分别为75.90％和76.83％,杂合度分别为0.199和0.218,遗传多样性指数分别为0.276和0.288,种群间的遗传距离为0.015;16S rRNA基因检测的种内遗传变异较低,马来西亚和海南种群的核苷酸多样性分别为0.011和0,种群之间的遗传距离为0.008;马来西亚种群比海南种群的遗传变异水平要高得多,且海南种群可能起源于马来西亚种群;进行遗传选育时可考虑引进马来西亚亲虾作为奠基群体.     

Genetic and biochemical differentiation in Vitis vinifera (Kabarcik) populations grown at different altitudes in Coruh Valley

We examined genetic differences of four Vitis vinifera populations (A, B, C, D) including local Kabarcik cultivar grown along an altitude gradient of 800, 900, 1000, and 1150 m above sea level in the Coruh Valley (800 m: A population; 900 m: B population; 1000 m: C population; 1150 m: D population). Leaf samples were used for both RAPD and fatty acid analysis. A total of 60 individuals with 15 individuals per population were included in this study. RAPD analyses showed various band sizes, which ranged from 250 to 3000 bp. Mean polymorphic locus ratios were determined as 96.29% considering four populations. The highest percentage of polymorphic loci (97.8%) was produced by the highest altitude. Thirty-two different fatty acids were found; linoleic acid was the most common in all four populations. According to the dendograms obtained from statistical analyses of RAPD and fatty acid profiles the populations that were close to each other in terms of geographical distance also were similar genetically.     

Differentiation between natural and cultivated populations of Medicago sativa (Leguminosae) from Spain: analysis with random amplified polymorphic DNA (RAPD) markers and comparison to allozymes

The conservation of a crop's wild relatives as genetic resources requires an understanding of the way genetic diversity is maintained in their populations, notably the effect of crop-to-wild gene flow. In this study, the amount of differentiation between natural and cultivated populations of Medicago sativa was analysed using random amplified polymorphic DNA (RAPD) markers and an extension of the AMOVA procedure adapted to autotetraploid organisms. Simulations of structured populations were performed to test whether AMOVA provides estimates of population structure in autotetraploids that can be directly compared to those obtained for allozyme data. Simulations showed that straight phi-statistics allow a good estimation of population differentiation when unbiased allelic frequencies are used to correct the conditional expectations of squared genetic distances. But such unbiased estimates can not be practically guaranteed, and population structure is notably overestimated when some populations are fixed for the presence of amplified fragments. However, removing fixed loci from the data set improves the statistical power of the test for population structure. The genetic variation of 15 natural and six cultivated populations of M. sativa was analysed at 25 RAPD loci and compared to estimates computed with allozymes on the same set of populations. Although RAPD markers revealed less within-population genetic diversity than allozymes, the quantitative and qualitative patterns of population structure were in full agreement with allozymes. This confirmed the conclusions drawn from the allozymic survey: crop-to-wild gene flow occurred in many locations, but some other mechanisms opposed cultivated traits to be maintained into natural populations.     

Genetic Relationships Among Wild and Cultivated Accessions of Curry Leaf Plant (Murraya koenigii (L.) Spreng.), as Revealed by DNA Fingerprinting Methods

Murraya koenigii (L.) Spreng. (Rutaceae), is an aromatic plant and much valued for its flavor, nutritive and medicinal properties. In this study, three DNA fingerprinting methods viz., random amplification of polymorphic DNA (RAPD), directed amplification of minisatellite DNA (DAMD), and inter-simple sequence repeat (ISSR), were used to unravel the genetic variability and relationships across 92 wild and cultivated M. koenigii accessions. A total of 310, 102, and 184, DNA fragments were amplified using 20 RAPD, 5 DAMD, and 13 ISSR primers, revealing 95.80, 96.07, and 96.73% polymorphism, respectively, across all accessions. The average polymorphic information content value obtained with RAPD, DAMD, and ISSR markers was 0.244, 0.250, and 0.281, respectively. The UPGMA tree, based on Jaccard’s similarity coefficient generated from the cumulative (RAPD, DAMD, and ISSR) band data showed two distinct clusters, clearly separating wild and cultivated accessions in the dendrogram. Percentage polymorphism, gene diversity (H), and Shannon information index (I) estimates were higher in cultivated accessions compared to wild accessions. The overall high level of polymorphism and varied range of genetic distances revealed a wide genetic base in M. koenigii accessions. The study suggests that RAPD, DAMD, and ISSR markers are highly useful to unravel the genetic variability in wild and cultivated accessions of M. koenigii.     

Isolation and characterization of microsatellite DNA loci in sea bass,Lates calcarifer Bloch

Polymerase chain reaction (PCR)‐based isolation of microsatellite arrays (PIMA) technique was used to isolate seven polymorphic microsatellite loci in sea bass, Lates calcarifer Bloch. A total of 62 samples of wild and cultivated sea bass collected from a few populations within Peninsular Malaysia were used in the study. For seven polymorphic loci, the number of alleles ranged from four to nine and locus heterozygosities ranged from 0.710 to 1.000. The loci will be useful for studying population structure, genetic variability of wild and hatchery stocks of L. calcarifer and broodstock management purposes.     

Genetic variation within and among populations of a wild rice Oryza granulata from China detected by RAPD and ISSR markers

Genetic variation within and between five populations of Oryza granulata from two regions of China was investigated using RAPD (random amplified polymorphic DNA) and ISSR (inter-simple sequence repeat amplification) markers. Twenty RAPD primers used in this study amplified 199 reproducible bands with 61 (30.65%) polymorphic; and 12 ISSR primers amplified 113 bands with 52 (46.02%) polymorphic. Both RAPD and ISSR analyses revealed a low level of genetic diversity in wild populations of O. granulata. Furthermore, analysis of molecular variance (AMOVA) was used to apportion the variation within and between populations both within and between regions. As the RAPD markers revealed, 73.85% of the total genetic diversity resided between the two regions, whereas only 19.45% and 6.70% were present between populations within regions and within a population respectively. Similarly, it was shown by ISSR markers that a great amount of variation (49.26%) occurred between the two regions, with only 38.07% and 12.66% between populations within regions and within a population respectively. Both the results of a UPGMA cluster, based on Jaccard coefficients, and pairwise distance analysis agree with that of the AMOVA partition. This is the first report of the partitioning of genetic variability within and among populations of O. granulata at the DNA level, which is in general agreement with a recent study on the same species in China using allozyme analysis. Our results also indicated that the percentage of polymorphic bands (PPB) detected by ISSR is higher than that detected by RAPD. It seems that ISSR is superior to RAPD in terms of the polymorphism detected and the amplification reproducibility. Received: 29 March 2000 / Accepted: 15 May 2000     

新疆桑属植物栽培居群的遗传多样性研究

应用RAPD分子标记对新疆不同地区栽培的桑属植物2种3个分类群共11个居群进行了遗传多样性研究。结果表明,新疆桑属栽培植物中虽然存在较为丰富的遗传多样性,多态位点比率(PPB)为87．39％,Shannon多样性指数为0．3997,但在栽培居群内的遗传变异水平相对较低;在不同居群间遗传变异水平仔住很人差异,各居群的多态位点比率(PPB)为4．5％至45．95％,Shannon多样性指数为0．0312至0．2339;白桑(Morus alba L．)及其变种鞑靼桑(Morus alba L．var．tatarica)居群内的遗传变异水平远高于黑桑种(Morus nigra)。新疆桑属植物栽培居群内较低的遗传变异水平与其采用扦插等无性繁殖方式有关。分析全部的遗传变异显示,11个栽培居群之间的基因分化系数(Gst)为0．3541,其中桑及其变种9个居群间的基因分化系数为0．4597,黑桑种2个居群问的基因分化系数为0．4728。AMOVA分析表明,在全部遗传变异中,黑桑种和白桑种2个物种之间的遗传变异占59．16％,居群间遗传变异为17．46％。遗传距离和聚类分析也表明,黑桑种和白桑种及其变种鞑靼桑之间存在很大的遗传分化。     

我国盾叶薯蓣居群遗传结构分析

利用随机扩增多态DNA(RAPD)标记,分析研究了中国11个盾叶薯蓣居群82个个体的遗传多样性与遗传结构,15个寡聚核苷酸引物扩增共得到108条带,其中96条为多态带,占88．89％。Shannon多样性指数(I)为0．3093,居群水平的变异从0．1564到0．3098,物种水平的Nei基因多样度(h)为0．2499,居群水平的变化范围为0．1607到0．2137。遗传变异分析表明,物种水平的基因分化系数Gst为0．3415,居群间的基因流Nm为0．9641,居群间遗传交换小。分子方差分析(AMOVA)表明,居群内变异为68．96％,地区间变异为19．45％,居群问变异为11．58％。聚类结果以长江为界,将盾叶薯蓣分为南北两个大类群。研究结果对盾叶薯蓣种质的迁地保护有重要意义。     

Patterns of Genetic Variation in in and ex situ Populations of the Threatened Chilean VineBerberidopsis corallina , Detected Using RAPD Markers

Berberidopsis corallina Hook. f. (Berberidopsidaceae) is a threatenedvine, endemic to the temperate rainforests of southern Chile.A RAPD analysis was carried out to assess the extent of geneticvariation in remaining wild populations and in British cultivatedplants, to assess the value of the latter for ex situ conservation.A total of 90 individuals (54 wild, 35 cultivated) were analysed,and a total of 54 polymorphic bands produced. A pairwise distancemeasure calculated from the RAPD data was used as input forprincipal coordinate analysis (PCO) and analysis of molecularvariance (AMOVA). AMOVA indicated that an exceptionally highproportion of total genetic variation (54.8%) was recorded amongpopulations; pairwise     

鸢尾属植物遗传多样性的 RAPD和ISSR分析

应用RAPD和ISSR标记技术,对来自不同产地的鸢尾属(IrisL.)4个野生种的遗传多样性进行了分析。结果表明,12个RAPD和ISSR引物分别扩增出225和196条带,多态性条带分别为215和196条,多态性条带百分率分别为95.56%和100.00%;种间总基因多样度分别为0.368 9和0.357 5、种内基因多样度分别为0.107 7和0.138 0,表明鸢尾属种间遗传多样性较高,且种间变异大于种内变异。4个野生种中,蝴蝶花(I.japonicaThunb.)的遗传组成较为丰富。此外,种内遗传关系与地理分布和环境差异有一定的相关性。     

Analysis of genetic diversity and structure in Ethiopian populations of Phytolacca dodecandra using RAPD

The genetic diversity and structure in 17 wild populations (249 individuals) of Phytolacca dodecandra (endod) sampled along altitudinal gradients of 1600-3000 meters above sea level (m.a.s.l.) in Ethiopia was studied using random amplified polymorphic DNA (RAPD). A total of 70 polymorphic loci (P) scored from 12 RAPD primers were used to calculate different diversity indices within and between populations, habitats, geographical regions, climatic zones and altitude groups. The number of polymorphic loci and overall Shannon information measure (H) in the populations varied from 30 to 55 and from 0.228 to 0.418, respectively. In general, differences in population variability were found significantly correlated to effective population size. Both P and H were significantly higher in an undisturbed than in a disturbed habitat, and in the lowland and central-highland than in the highland altitude group. However, for both parameters the differences were not statistically significant between regions and climatic zones. Genetic distance between populations varied from 0.301 to 0.628. Cluster analysis performed using the genetic distance matrix revealed a clear separation of the highland populations (2501-3000 m.a.s.l.) from those of the lowland/central-highlands (1600-2500 m.a.s.l.) irrespective of their geographical regions and climatic zones. Analysis of molecular variance (AMOVA) indicated that differences in habitat, geographical regions and climatic zones explained 4.6%, 2.5% and 4.6%, respectively. But none of these differences were significant. Altitude explained 17.2% of the total variance and was highly significant. The data, therefore, clearly indicated the association of genetic structure in endod with altitude. The proportion of RAPD variation found among populations (21.2-35.0%) was somewhat intermediate between values reported for selfing and outcrossing species. The fixation index (FST) values (0.350 to 0.384) indicated very high genetic differentiation among populations.     

橡胶树种质资源遗传多样性研究——Ⅰ．速生种质遗传多样性RAPD分析

应用RAPD技术对8份野生种质和12份栽培种质进行遗传多样性分析,筛选到18个具有多态性扩增的引物．共扩增出128条带。据Nei-Li相似系数将20份材料分别聚为野生种质和栽培种质两大类。5个野生种质聚为野生种质类群,12个栽培种质和3个野生种质聚为栽培种质类群。研究结果表明,RAPD技术用于橡胶树种质资源研究,能够为野生种质优良特性导入栽培种质提供分子水平的参考依据。     

Genetic variation in wild sorghum (Sorghum bicolor ssp. verticilliflorum (L.) Moench) germplasm from Ethiopia assessed by random amplified polymorphic DNA (RAPD)

The extent and distribution of genetic variation in wild sorghum (Sorghum bicolor ssp. verticilliflorum (L.) Moench) collected from five different geographical regions in Ethiopia were analyzed using random amplified polymorphic DNA (RAPD) markers for 93 individuals representing 11 populations. Nine decamer primers generated a total of 83 polymorphic bands with 8-12 bands per primer and a mean of 9 bands across the 93 individuals. The amount of genetic variation among the populations (H = 0.37) and among the geographical region (H = 0.44) was low to moderate, despite the high degree of polymorphic bands per primer. Similarly, the mean genetic distance (0.08) among populations as well as among regions of origin (0.04) of the population was found to be low. The low genetic variation may be due to the reduced population size of the wild sorghum in Ethiopia because of habitat change. Partitioning of the genetic variation into between and within the population as well as between and within the regions of origin revealed that 75% and 88% of the variation was found within the populations and within the regions, respectively. Cluster analysis of genetic distance estimates further confirmed low level of differentiation of wild sorghum populations both on population and regional bases. The implications of the results for genetic conservation purposes are discussed.     

AFLP analysis of the diversity and phylogeny of Lens and its comparison with RAPD analysis

AFLP and RAPD marker techniques have been used to evaluate and study the diversity and phylogeny of 54 lentil accessions representing six populations of cultivated lentil and its wild relatives. Four AFLP primer combinations revealed 23, 25, 52 and 48 AFLPs respectively, which were used to partition variation within and among Lens taxa. The results of AFLP analysis is compared to previous RAPD analysis of the same material. The two methods provide similar conclusions as far as the phylogeny of Lens is concerned. The AFLP technique detected a much higher level of polymorphyism than the RAPD analysis. The use of 148 AFLPs arising from four primer combinations was able to discriminate between genotypes which could not be distinguished using 88 RAPDs. The level of variation detected within the cultivated lentil with AFLP analysis indicates that it may be a more efficient marker technology than RAPD analysis for the construction of genetic linkage maps between carefully chosen cultivated lentil accessions.     

Genetic differentiation among common and selected hatchery populations of flounder: Evidence from RAPD markers

Randomly amplified polymorphism DNA (RAPD) analysis was performed in order to evaluate one common population and two selected hatchery populations of flounder Paralichthys olivaceus. A total of 90 individuals belonging to three populations were screened using 12 different RAPD primers. A total of 71 loci were produced in the three studied populations, and 43.5%, 42.4% and 42.2% of these loci were polymorphic over all the genotypes tested in common, susceptible and resistant populations, respectively. The number of loci detected by single primers ranged from four to eight. The average heterozygosites of common, susceptible and resistant populations were 0.112, 0.103 and 0.111, respectively. Compared with the common population, the two selected hatchery populations, susceptible and resistant, showed some genetic differences including a smaller number of loci, a smaller number of polymorphic loci, a smaller number of genotypes and a smaller Shannon index. The present study confirmed that it is important to detect the genetic variability of the selected hatchery population for the conservation of natural flounder resources.