日本落叶松群体的叶绿体SSR分析

利用叶绿体微卫星（cpSSR）分子标记对日本国内的7个日本落叶松（Larix kaempferi）群体遗传结构进行了研究。11对cpSSR引物中筛选出的3对多态性引物,共产生10个长度不同片段,在197个样品中组合出现10个不同的单倍型（haplotype）。各群体的单倍型差异较大。cpSSR基因座揭示了日本落叶松的遗传变异：平均等位基因数A=3.33,平均有效等位基因数NE=1.20,基因多样度HE=0.17,群体间变异占总群体变异的5.37%,遗传变异主要来自于群体内个体间。Abstract: Genetic structure of seven populations in Larix kaempferi in Japan was studied by use of cpSSR markers. Ten different length fragments in and ten different kinds of haplotypes were reduced in 197 samples based on 3 pairs of polymorphic primers screened from 11 pairs of primers. There were significant variant haplotypes among the populations. The genetic variation in the populations of Larix kaempferi was detected by using cpSSR with the number of average loci A=3.33, the number of average efficient loci NE=1.20, gene diversity HE=0.17 and 5.37% variation from different populations. The genetic variation was mainly from individuals in population.     

Use of Random Amplified Polymorphic DNA Analysis for Economically Important Food Crops

The objective of this review is to summarize numerous studies on the use of the random amplified polymorphic DNA （RAPD） technique on rice, corn, wheat, sorghum, barley, rye, and oats to examine its feasibility and validity for assessment of genetic variation, population genetics, mapping, linkage and marker assisted selection, phylogenetic analysis, and the detection of somaclonal variation. Also we discuss the advantages and limitations of RAPD. Molecular markers have entered the scene of genetic improvement in different fields of agricultural research. The simplicity of the RAPD technique made it ideal for genetic mapping, plant and animal breeding programs, and DNA fingerprinting, with particular utility in the field of population genetics.     

Analysis of genetic diversity in the endangered Hucho taimen from China

Hucho taimen are listed as endangered in China. The population size has declined recently, prompting an increase in the level of listing from grade three in 2002 to grade five in 2006. We analyzed the genetic diversity of wild populations using 17 microsatellite markers to establish a scientific basis for conservation of this species. We collected tissue samples from four populations in the Heilongjiang River basin: Huma River (HM), Hutou (HT), Haiqing (HQ), and Zhuaji (ZJ). A total of 21 loci were amplified, 18 of which were polymorphic. The number of alleles per locus ranged from 2 to 9 (mean: 4.1905). There were 13 highly polymorphic loci and 5 moderately polymorphic loci. Analysis of five genetic diversity parameters (Na, Ne, Ho, He, and PIC) suggested moderate levels of diversity within the populations. The populations were ranked HT > HQ > ZJ > HM, but the differences in diversity were not statistically significant (P > 0.05). A comparison of variation among all four populations suggested Hardy–Weinberg disequilibrium at 20% of the loci. Genetic differentiation (Fst) was 0.0644 and the gene flow among populations was estimated at 3.36 individuals per generation. The majority of diversity (93.88%) occurred among individuals within a population. In contrast, relatively little (6.12%) of the genetic diversity was distributed between the populations. An analysis of genetic differentiation and genetic distance between pairs of populations revealed that both parameters were higher in comparisons of the HM population to the HT, HQ, and ZJ populations than among the three latter populations. This suggests that the HM population has a distinct genetic structure. We hypothesize that habitat degradation and excessive fishing, not low genetic diversity, has caused the decline in H. taimen populations. However, this species should be protected from further declines in genetic diversity.     

Analysis of genetic diversity in the endangered Hucho taimen from China

Hucho taimen are listed as endangered in China. The population size has declined recently, prompting an increase in the level of listing from grade three in 2002 to grade five in 2006. We analyzed the genetic diversity of wild populations using 17 microsatellite markers to establish a scientific basis for conservation of this species. We collected tissue samples from four populations in the Heilongjiang River basin: Huma River (HM), Hutou (HT), Haiqing (HQ), and Zhuaji (ZJ). A total of 21 loci were amplified, 18 of which were polymorphic. The number of alleles per locus ranged from 2 to 9 (mean: 4.1905). There were 13 highly polymorphic loci and 5 moderately polymorphic loci. Analysis of five genetic diversity parameters (Na, Ne, Ho, He, and PIC) suggested moderate levels of diversity within the populations. The populations were ranked HT > HQ > ZJ > HM, but the differences in diversity were not statistically significant (P > 0.05). A comparison of variation among all four populations suggested Hardy–Weinberg disequilibrium at 20% of the loci. Genetic differentiation (Fst) was 0.0644 and the gene flow among populations was estimated at 3.36 individuals per generation. The majority of diversity (93.88%) occurred among individuals within a population. In contrast, relatively little (6.12%) of the genetic diversity was distributed between the populations. An analysis of genetic differentiation and genetic distance between pairs of populations revealed that both parameters were higher in comparisons of the HM population to the HT, HQ, and ZJ populations than among the three latter populations. This suggests that the HM population has a distinct genetic structure. We hypothesize that habitat degradation and excessive fishing, not low genetic diversity, has caused the decline in H. taimen populations. However, this species should be protected from further declines in genetic diversity.     

Development and Characterization of 15 Polymorphic Micro satellite Markers for a Highly Adaptive and Wide-range Frog （Microhyla fissipes）

In order to analyze population genetic structure at multiple spatial scales, microsatellite loci were developed for the ornamented pygmy flog （Microhylafissipes）, and 15 polymorphic microsatellite loci were successfully screened from 105 individuals, of which 82 from four populations distributed in the Sichuan Basin and 23 from the Sangzhi population in western Hunan. Five loci were found to deviate significantly from Hardy-Weinberg equilibrium in one to three popu lations, probably due to small sample size or null alleles. The average number of alleles in all loci was 8.5, ranging from 4 to 13, and the observed and expected heterozygosity ranged from 0.26 to 0.90 and 0.63 to 0.90, respectively. The Sangzhi population and the remaining four populations can be clearly separated using Bayesian clustering methods, showing that the genetic structure of M. fissipes was probably affected by the topography, especially mountain barriers. These polymorphic microsatellite loci could be used for further study on the landscape genetics of this highly adaptive and widely distributed species.     

藏鸡群体遗传多样性研究

藏鸡的体型外貌和生活习性与红色原鸡非常相似,是具有自己独特群体遗传特性的高原地方鸡种。为了有效保护并合理利用这一遗传资源,我们采用多重PCR与半自动荧光标记微卫星聚丙烯酰胺凝胶电泳相结合的方法检测了20个微卫星基因座的多态性,并随机抽取藏鸡群体中部分个体进行个体体形特征与生产性能的统计。结果表明藏鸡群体的20个微卫星基因座的多态等位基因数为4~10个,平均值为7.25个/基因座,多态信息含量（CPI）和杂合度（H）平均值分别为0.67、0.74。大染色体较小染色体的微卫星标记多态性程度要高。藏鸡群体的微卫星基因座多态性丰富,也解释了生产性能不均,外貌表现迥异的群体遗传特性。 Abstract: Morphological traits and living habit of Tibetan chicken, which is an aboriginal chicken breed on plateau with its own characteristic populational genetic features, are in great common with the Red Jungle Fowl, the assumed ancestry of domestic chicken. To fully exploit this chicken resource, Multiplex PCR with semi-automated polyacrilamide gel electrophoresis (PAGE) using fluorescently labeled microsatellite primers was used to detect the polymorphism at 20 microsatellite loci. At the same time, we randomly test the individual morphology and performance. It showed that numbers of polymorphic alleles were 4-10, with mean value 7.25 per locus. Polymorphism Information Content (CPI) and Heterozygosity (H) had mean values 0.67 and 0.74, respectively. Macrochromosomes had relatively higher polymorphism than microchromosomes(P>0.05). In all, high polymorphisms at microsatellite loci related to the uneven production performance and morphological discrepancy of population genetic characteristics in Tibetan chicken.     

栓皮栎天然群体SSR遗传多样性研究

利用微卫星(SSR)标记对我国4个省内的5个栓皮栎（Quercus variabilis Bl.）天然群体的遗传多样性进行了研究。16对SSR标记揭示了栓皮栎丰富的遗传多样性：等位基因数（A）平均8.4375个,有效等位基因数(Ne)平均为5.9512个,平均期望杂合度(He)0.8059,Nei多样性指数(h)为0.8041。栓皮栎自然分布区中心地带的群体具有较高的遗传多样性,而人为对森林的破坏将降低林木群体的遗传多样性。栓皮栎群体的变异主要来源于群体内,群体间分化较小,遗传分化系数仅为0.0455。此外,栓皮栎群体间的遗传距离与地理距离之间存在显著的正相关。这些遗传信息为栓皮栎遗传多样性的保护和利用提供了一定依据。Abstract: Genetic diversity of five Quercus variabilis natural populations in four provinces of China was studied with microsatellite (SSR) markers. A relatively high level of genetic diversity was detected in Q. variabilis species with 16 polymorphic microsatellite loci. Average number of alleles (A) and effective number of alleles (Ne) were 8.4375 and 5.9512 respectively. The mean expected heterozygosity (He) was 0.8059 and Nei diversity index (h) was 0.8041. Higher diversity was found with the populations from the central range of the species in contrast to those from peripheral areas and human activities might decrease the genetic diversity of populations. The majority of genetic variation occurred within populations, which could be concluded from the low coefficient of genetic differentiation (Fst=0.0455). In addition, significant correlation was found between geographical distance and genetic distance. All these results present a basis to the conservation and utilization of genetic diversity of Quercus variabilis.     

Mating system and genetic diversity of a rare desert legume Ammopiptanthus nanus （Leguminosae）

Ammopiptanthus nanus is an endangered evergreen shrub endemic to the deserts of central Asia and plays an important role in delaying further desertification. We examined allozyme variation and AFLP diversity in A. nanus populations and investigated the mating system of this species using progeny arrays assayed for polymorphic allozyme loci. Mating system analysis in the Keyi＇eryongke＇er population showed low levels of outcrossing, and strong inbreeding depression. Low levels of genetic variation were detected at both population （allozyme, Pp=14.0%, A=l.14, He=0.031; AFLP, Pp=14.5%, Shannon＇s information index I=0.063） and species （allozyme, Pp=21.1%, A=1.21, He=0.040; AFLP, Pp=20.9%, I=0.083） levels; while moderate genetic differentiation existed among populations, as indicated by allozymes （Gsa-=0.081） and AFLP （GST=0.151-0.193）. Founder effect, bottlenecks in evolutionary history, the mixed mating system and co-ancestry may have influenced the level of genetic diversity in A. nanus. Markers of both types provide new insights for conservation management, indicating that the Biao＇ertuokuoyi and Keyi＇eryongke＇er populations should be given priority for in situ conservation and regarded as seed sources for ex situ conservation.     

不同地区库蚊复组群体的同工酶遗传多样性研究

采用水平切片淀粉凝胶电泳的方法,对分布于我国5省的8个库蚊复组（Culex pipiens complex）野生群体的遗传多样性进行研究,分析了4个酶系统7个基因座(ME、MDH-1、MDH-2、MDH-3、GPD、EST-2、EST-3)的酶谱资料。结果显示：（1）群体内存在不同程度的遗传变异（He为0.098～0.41）;（2）较低的基因流水平（Nm=0.64）使遗传漂变起主要作用,造成群体之间的遗传分化（Gst=0.303）,而总群体的遗传多样性相对富集于群体之内(Hs/Dst=2)。（3）库蚊群体的遗传结构属于距离隔离模式。（4）群体间的遗传一致性(或遗传距离)反映出群体间的遗传分化程度,也表明与地理位置存在对应关系。Abstract: Eight field populations of Culex pipiens complex collected from five provinces (Guangdong, Henan, Shandong, Beijing and Yunnan) in 2001 were used to study genetic diversity by starch gel electrophoresis. Data from seven loci (ME、MDH-1、MDH-2、MDH-3、GPD、EST-2、EST-3) of four isozymes were analyzed by software Biosys2.0 and FSTAT(Version 2.9.3). The results were as follows: (1) The values of He (from 0.098 to 0.41) indicated genetic variabilities of different degree in populations.(2)The low level of gene flow (Nm=0.64) could not prevent genetic drift to cause the gene differentiation between populations. The genetic diversity between populations attributed to the genetic diversity of total populations is small (Gst =0.303), and the great part is accumulated within populations (Hs/Dst=2). (3) The genetic structure of Culex pipiens complex population was the isolation-by-distance model. (4) The genetic identity (or genetic distance) revealed the scale of genetic differentiation between populations which related to the collection sites.     

Genetic diversity of the endangered species Rosa rugosa Thunb. in China and implications for conservation strategies

Rosa rugosa Thunb. is one of the dominant and important shrub species in estuary dunes and shingle beaches of northern China. However, its area of distribution, the number of populations, and the size of each population have decreased rapidly in the past two decades because of habitat degradation and loss. Random amplified polymorphic DNA markers were used to determine the genetic diversity of four remaining large natural populations of R. rugosa and to discuss an effective conservation strategy for this endangered species in China. High genetic variations were detected in R. rugosa populations in China. The mean percentage of polymorphic loci （P%） within four local populations was 57.99%, with the P% of the total population being 75.30%. Mean Shannon＇s information index （H0） was 0.2826, whereas total Ho was 0.3513. The genetic differentiation among populations was 0.1878, which indicates that most genetic diversity occurs within populations. Population Tumenjiang （TMJ） showed the highest genetic diversity （P% = 66.27%; H0 = 0.3117） and contained two exclusive bands. Population Changshandao （CSD） showed higher genetic diversity （P% =59.04%; H0 = 0.3065）. Populations TMJ and CSD contained 95.33% and 99.33%, respectively, of loci with moderate to high frequency （P〉0.05） of the total population. These results indicate that populations TMJ and CSD should be given priority for in situ conservation and regarded as seed or propagule sources for ex situ conservation. The results of the present study also suggest that R. rugosa in China has become endangered as a result of human actions rather than genetic depression of populations; thus, human interference should be absolutely forbidden in R. rugosa habitats.     

Genetic distance between two sibling species of the Aedes mariae complex (Diptera, Culicidae)

Two sibling species of the mariae complex of the Aedes genus have been studied: Ae. mariae and Ae. zammitii. Thee mosquitoes are allopatric and show similar adaptations to rocky mediterranean coasts. The isolating mechanisms between the two species are well studied. A partial sterility of hybrid F1, limited to males, has been found with laboratory cross experiments. Strong pre-mating isolating mechanisms were shown in nature by means of release experiments, the frequency of hybrids never exceeding 2% without evidence of introgression. We analyzed genetic variation at 26 enzyme loci in a population of each species: 35% of loci were polymorphic, with an observed mean heterozygosity of 0.07 in Ae. mariae and 0.06 in Ae. zammitii; 6 loci allow discrimination between the two species at a probability of at least .99. Nei's measures of genetic identity and genetic distance are respectively I = 0.6096 and D = 0.2828. The distribution of genetic identities relative to loci is strongly bimodal, reflecting a different contribution of highly variable and fast evolving loci on one side and conservative and slowly evolving loci on the other. We consider, on the base of various experimental data (see Powell, 1975), in the first class ("fast evolving" loci) both variable substrate and regulatory enzymes, in the second ("slow evolving" loci) non regulatory enzymes. Values of genetic distance calculated separately for the "fast" (54% of the loci studied) and "slow" (46%) evolving loci are respectively Df = 0.41 and Ds = 0.03, showing that the main contribution to genetic distance in the first period of divergence is due to fast evolving loci, whose rate of evolution is about ten times more rapid with respect to slow evolving loci.     

刚毛柽柳天然居群遗传多样性初探

柽柳是荒漠地区主要的灌木资源树种。以刚毛柽柳为代表,运用RAPD技术分析了广布于新疆境内9个刚毛柽柳(Tamarix hispida L．)天然居群的遗传多样性及居群间的遗传分化。10条随机引物检测到157个可重复的位点,其中多态位点155个,占总位点数的98．7％。由Shannon表型多样性指数和Nei基因多样性指数估计居群间遗传分化百分比分别为62．5％和55．30％,表明刚毛柽柳种内的遗传变异主要存在于居群间。根据以上结果,我们认为新疆境内刚毛柽柳天然居群的遗传多样性很丰富,居群间分化程度较高;繁育系统属于一种自交和不完全异交混合的交配类型;形成并维持其分布格局的主要因素是基因流的隔离。     

Allozyme frequencies in New Jersey and North Carolina populations of Atlantic white-cedar, Chamaecyparis thyoides (Cupressaceae)

The present study was conducted to assess the distribution of genetic variation within and among populations of Chamaecyparis thyoides in both marginal and centrally located populations. Allozyme frequency analyses of ten loci from foliage of four New Jersey populations and two North Carolina populations of C. thyoides showed polymorphic loci = 50%, mean number of alleles per locus = 2.8, effective number of alleles per locus = 1.17, and expected heterozygosity = 0.14. Diversity was highest in two populations from southern New Jersey. The isolated population at High Point, New Jersey had only two polymorphic loci and expected heterozygosity of 0.03. There was no correlation between genetic and geographic distances among populations, implying that cedar must have possessed some means of long-distance dispersal at the end of the last glacial period, rather than advancing northward step by step.     

凉水国家自然保护区天然红松林遗传变异的RAPD分析

采用随机扩增多态DNA(random amplified polymorphic DNA RAPD)技术,研究了凉水国家自然保护区天然红松林的遗传变异水平及其分布规律。16个10bp长度的随机引物在8个实验样地内72个个体中共检测了96个位点,其中55个是多态位点。在种水平上,红松的多态位点比率为P=58.51%;Nei's遗传变异指数为H=0.2868;Shannon's指数为I=0.3654,所有的变异中,有92.47%的变异存在于样地内, 7.53%的变异存在于样地间。根据各遗传多样性在不同样地的分布,初步探讨了红松遗传变异水平与其种群发生及生境的相互关系。     

不同海拔高度大血藤群体遗传多样性的RAPD分析及其与环境因子的相关性

利用 RAPD技术分析了分布于浙江省天台山 3个不同海拔高度的天然大血藤群体的遗传多样性、遗传分化以及与环境因子的相关性。 13种随机引物在 3 6株个体中共检测到 88个可重复的位点 ,其中多态位点 74个 ,总多态位点百分率为84.0 9% ,大血藤具有丰富的遗传多样性。 Shannon信息指数显示的遗传多样性以海拔 950 m的群体为最高 ,其次是海拔 73 0 m的群体 ,最低的是海拔 52 0 m的群体 ;群体内的遗传多样性占总遗传多样性的 43 .68% ,群体间的遗传多样性占 56.3 2 %。 Nei指数估计大血藤群体间的遗传分化系数为 0 .540 6,大血藤群体间的基因流很低。大血藤海拔 73 0 m群体与海拔 52 0 m群体的遗传相似度较高 ,海拔 950 m群体与其它两群体的遗传相似度较低。大血藤群体内的遗传多样性与土壤总氮呈极显著的正相关。     

Inheritance of isozyme variation and heterozygosity in Pinus ponderosa

Techniques are presented to detect 23 isozyme loci in the long-lived perennial plant, ponderosa pine. Meiotically derived megagametophyte from seeds is used to examine directly the segregation of allelic variants. Approximately seven seeds were initially examined for 12 enzymes from each of 47 trees from ten stands throughout the northern Rocky Mountain region. Additional seeds were also examined from selected families to confirm the inheritance of observed electrophoretic variants at 13 polymorphic loci and to estimate linkage relationships. Significant nonrandom segregation was consistently detected for three pairs of loci: ADH-1: AAT-2, ADH-1: PGI-1, and LAP-2: 6PG-1. Preliminary estimates of population parameters reveal a relatively high average heterozygosity (H=0.123). This is partitioned into a high amount of genetic variation within local stands, with only approximately 12% of the total heterozygosity resulting from genic differences between stands.Funds for this study were made available under the McIntire-Stennis program of the Forest, Range, and Conservation Experiment Station of the School of Forestry, University of Montana.     

The Genetic Structure of Natural Populations of DROSOPHILA MELANOGASTER. Xviii. Clinal and Uniform Genetic Variation over Populations

It has been reported in the previous papers of this series that in the eastern United States and Japan there is a north-to-south cline of additive genetic variance of viability and that the amount of the additive genetic variance in the northern population can be explained by mutation-selection balance. To determine whether or not the difference in the genetic variation in northern and southern populations can be explained by the differences in mutation rate and/or effective population size, numerical calculations were made using population genetic parameters. In addition, the average heterozygosities of the northern and southern populations at ten of 19 polymorphic structural loci surveyed were estimated in relation to the cline of additive genetic variance of viability, and the following findings were obtained. (1) The changes in mutation rate and population size cannot simultaneously explain the difference in additive genetic variance and inbreeding decline between the northern and southern populations. Thus, the operation of some kind of balancing selection, most likely diversifying selection, was suggested to explain the observed excess of additive genetic variance. (2) Estimates of the average heterozygosities of the southern population were not significantly different from those of the northern population. Thus, it was strongly suggested that the excess of additive genetic variance in the southern population cannot be caused by structural loci, but by factors outside the structural loci, and that protein polymorphisms are selectively neutral or nearly neutral.     

Genetic variability and differentiation in the larch populations within the range of Larix olgensis A. Henry in Primor'e region

The level of within- and among-population variation of larch inhabiting the range of Larix olgensis A. Henry in Primorye was estimated on the basis of 440 RAPD loci identified by means of 12 random primers. In ten population examined, the proportion of polymorphic loci was 35-60%, the average expected heterozygosity varied from 0.1340 to 2169, and the average gene flow estimate was 1.38. According to Fisher's test for heterogeneity, the pairwise differences of the fragment frequencies between the populations were statistically significant. The subdivision index G(ST) = 0.2663 indicated that the interpopulation variation component accounted for approximately 27% of the total variation. Coefficients of Nei's genetic distance between the populations varied from 0.0137 to 0.0934. Most of the samples with high support clustered according to the geographic positions relative to one another within the range. These results suggest that the populations examined are characterized by high genetic variation, like the larch populations of Siberia and the Russian Far East studied earlier, but, in contrast to the latter, exhibit higher among-population variability.     

不同生境三裂叶豚草种群的遗传结构

采用水平切片淀粉凝胶电泳测定了东北地区分布的不同生态环境条件下7个三裂叶豚草种群的遗传结构。统计分析了10个酶系统的10个位点,结果表明:三裂叶豚草种群内存在着丰富的遗传变异。多态位点百分率为80.00%,等位基因平均数为1.80,期望杂合度为0.375,遗传一致度和遗传距离为0.959和0.042。