Population genetics of Sargassum horneri (Fucales, Phaeophyta) in China revealed by ISSR and SRAP markers

Sargassum horneri is a common brown macro-alga that is found in the inter-tidal ecosystems of China. To investigate the current status of seaweed resources and provide basic data for its sustainable development, ISSR (inter simple sequence repeat) and SRAP (sequence related amplified polymorphism) markers were used to analyze the population genetics among nine natural populations of S. horneri. The nine studied populations were distributed over 2 000 km from northeast to south China. The percentage of polymorphic loci P% (ISSR, 99.44%; SRAP, 100.00%), Nei’s genetic diversity H (ISSR, 0.107-0.199; SRAP, 0.100-0.153), and Shannon’s information index I (ISSR, 0.157-0.291; SRAP, 0.148-0.219) indicated a fair amount of genetic variability among the nine populations. Moreover, the high degree of gene differentiation G st (ISSR, 0.654; SRAP, 0.718) and low gene flow N m (ISSR, 0.265; SRAP, 0.196) implied that there was significant among-population differentiation, possibly as a result of habitat fragmentation. The matrices of genetic distances and fixation indices (F st ) among the populations correlated well with their geographical distribution (Mantel test R=0.541 5, 0.541 8; P=0.005 0, 0.002 0 and R=0.728 6, 0.641 2; P=0.001 0, 0.001 0, respectively); the Rongcheng population in the Shandong peninsula was the only exception. Overall, the genetic differentiation agreed with the geographic isolation. The fair amount of genetic diversity that was revealed in the S. horneri populations in China indicated that the seaweed resources had not been seriously affected by external factors.     

Genetic differentiation of Japanese sardinella (Sardinella zunasi) populations in the Northwest Pacific revealed by ISSR analysis

Knowledge of population genetic structure plays an important role in fisheries management.In this research,In-ter-Simple-Sequence-Repeat(ISSR)markers were employed to evaluate the genetic structure of Japanese sardinella(Sardinella zun-asi)populations in the Northwest Pacific.Eighty seven individuals from 5 locations were screened using 4 highly polymorphic prim-ers.A total of 173 polymorphic loci were detected out of 191 loci amplified.Small but significant genetic differentiation was de-tected between the Chinese and Japanese populations by both AMOVA and pairwise FST analyses,which was further supported by cluster analysis.We consider that climate change during glaciations should be responsible for the genetic differentiation.Isolation by geographic distance among populations was observed,indicating that the distance might also lead to the genetic differentiation.However,no genetic structure was found within the populations off both the Chinese and Japanese coasts,indicating a high-level along-coast gene flow,which might result from ocean current transport and common ground for over-wintering.     

The loss of genetic diversity during captive breeding of the endangered sculpin, Trachidermus fasciatus, based on ISSR markers: implications for its conservation

Inter-simple sequence repeat (ISSR) markers were used to determine the genetic variation and genetic differentiation of cultured and wild populations of Trachidermus fasciatus, an endangered catadromous fish species in China. Six selected primers were used to amplify DNA samples from 85 individuals, and 353 loci were detected. Relatively low genetic diversity was detected in the cultured population (the percentage of polymorphic loci PPL = 73.80%, Nei’s gene diversity h = 0.178 2, Shannon information index ...     

The mycobiota of discoloured needles of the Swiss stone pine(Pinus cembra L.) in the Tatra Mountains(Poland)

The Swiss stone Pine(Pinus cembra L.) is an alpine species, fairly commonly occurring in the Alps and the Carpathians, close to the timberline. Natural sites of the Swiss stone pine in Poland are found exclusively in the Tatra Mountains, within the area of the Tatra National Park(TNP). In 2017, the health status of the needles of P. cembra was determined and their mycological analysis was carried out. As a result, 11 species of fungi were isolated from the needles showing disease symptoms, manifested by various shades of discoloration. The most frequently observed species was Fusarium oxysporum. It probably does not bring on disease symptoms, but may affect the development of other frequently isolated species(such as Sydowia polyspora, Lophodermium sp. and Lophodermium conigenum) that are pathogenic to Pinus spp.     

近江牡蛎两个野生种群的遗传多样性分析

采用RAPD分子标记和rDNA-ITS1序列分析了近江牡蛎Crassostrea rivularis湛江官渡和阳江程村野生种群的遗传多样性。12个RAPD引物共扩增出8838条片段,157个位点,平均每个引物可产生13个位点,片段长度在200～2200bp之间。湛江种群和阳江种群的多态位点比例分别为89.62%和89.57%,遗传多样性指数分别为0.4170和0.4334。种群间平均遗传距离为0.0327,平均遗传相似性为0.9681,平均遗传分化系数为0.0437。得到近江牡蛎18S、5.8S部分序列和ITS1全部序列,其中ITS1序列片段长度为478～485bp,共有11个变异位点,两个为转换(A/G),其他为插入/缺失(A/-、T/-)。湛江和阳江种群各获得8个单倍型,其中有一个单倍型为两个种群共享。两个种群的CG碱基平均含量较高,分别为58.29%和58.41%。种群间的遗传分化系数0.0254。结果说明,近江牡蛎湛江种群和阳江种群间具有较高的遗传多样性和较低的遗传分化。     

东、黄海鲐鱼群体遗传差异的RAPD分析

利用随机扩增多态DNA(RAPD)技术分别分析了五岛西部日本鲐、东海西部日本鲐和澳洲鲐三群体的样本,共产生226个分子标记,其中143个为多态性标记,多态百分率达到63.3%,每条引物产生的平均标记数为7.29。五岛西部日本鲐、东海西部日本鲐和澳洲鲐群体内遗传相似度分别为0.949、0.877和0.936,而群体间遗传距离依次为:五岛西部日本鲐-东海西部日本鲐(0.2357)<东海西部日本鲐-澳洲鲐(0.3030)<五岛西部日本鲐-澳洲鲐(0.3528),五岛西部日本鲐与东海西部日本鲐个体在UPGMA系统树独立聚类为两个类群,初步支持东、黄海的日本鲐存在东海西部和五岛西部的两个种群的观点。Shannon多样性指数表明,其遗传多样性大小依次为东海西部日本鲐、澳洲鲐、五岛西部日本鲐。     

运用RAPD技术对笛鲷属3种鱼的群体遗传学分析

应用RAPD技术,从9个系列180种随机引物中筛选出16种,对笛(鱼周)属的画眉笛(鱼周)(Lutja-nus vitta)、金焰笛(鱼周)(Lutjanus fulviflamma)、金带笛(鱼周)(Lutjanus vaigiensis)进行种群内及种群间遗传学分析,并利用UPGMA确定了它们之间的亲缘关系。结果表明,三种鱼的种内遗传多样性指数(H)分别为,画眉笛(鱼周)0.1949,金带笛(鱼周)0.1107,金焰笛(鱼周)0.1673;三者的多态位点比例(P)分别为69.4％、47.8％和59.0％;金带笛(鱼周)具有较低的遗传多样性,且全带笛(鱼周)与金焰笛(鱼周)有较近的亲缘关系。三种鱼共检出10个可作为种的特异性鉴定的条带,可用于种质鉴定。     

基于近缘EST-SSR引物的企鹅珍珠贝养殖和野生群体的遗传标记

利用近源物种马氏珠母贝的EST-SSR引物对企鹅珍珠贝DNA进行扩增,获得7对可扩增出目标条带的近缘分子标记,分析野生群体(YS)和养殖群体(YZ)企鹅珍珠贝的遗传多样性。结果显示,7个位点共获得26个等位基因;野生和养殖群体的等位基因数分别为3~5和3~4,平均期望杂合度(He)分别为0.623 5、0.496 8;平均观测杂合度(Ho)分别为0.431 8、0.302 8;HNUPM047位点的多态信息含量较低,为0.446 7,其他位点均在0.5以上,说明该遗传标记可提供比较丰富的遗传信息。表明养殖群体遗传多样性水平低于野生群体。     

运用RAPD技术分析3种罗非鱼的遗传多样性

应用RAPD技术,从7个系列140种随机引物中筛选出15个,对尼罗罗非鱼(Oreochromis niloticus)、奥利亚罗非鱼(O.aureus)和星洲银罗非鱼(O.sp.)进行遗传多样性分析。结果表明,尼罗罗非鱼、奥利亚罗非鱼、星洲银罗非鱼的多态位点比例(P)分别为54.7%、44.4%和56.0%,种内个体间遗传距离分别为0.145 0、0.115 6和0.141 3,种内遗传相似系数分别为0.855 0、0.884 6和0.858 7;种间遗传距离的聚类分析表明,星洲银罗非鱼与尼罗罗非鱼亲缘关系较近,一定程度上验证了星洲银罗非鱼的分类地位。     

Effect of weather conditions on the incidence of Lophodermium yellow needle blight in the dwarf mountain pine in the Karkonosze and Izerskie Mountains (Poland)

The study aimed to determine, by using a statistical model, the effect of weather conditions on the incidence of Lophodermium yellow needle blight causing by new species for science- Lophodermium corconticum, in the mountain dwarf pine growing in the subalpine Karkonosze Mountains and the Izerskie Mountains(Poland). Needles showed symptoms of yellow spots, gradual discolouration and premature fall in July. The assessment of healthiness of infected mountain dwarf pine needles spanned three years(2011- 2013) and was conducted in several test sites in the Karkonosze and Izerskie Mountains. The results were analyzed by taking into account the meteorological conditions. Field observations seem to indicate that the highest infestation of mountain dwarf pine occurs in June and July, while September and October see a significantly lower disease index in the Karkonosze Mountains. The lower indices of the infestation of mountain dwarf pine are characteristic for the vegetation in the Hala Izerska high mountain pasture; whereas the environmental conditions prevailing in the Kocio? Ma?ego Stawu cirque and above the Samotnia hostel are conducive to the development of Lophodermium yellow needle blight.     

蜂巢石斑鱼随机扩增多态性DNA的初步研究

采用RAPD技术分析了湛江沿海野生蜂巢石斑鱼的遗传多样性 ,从 6个系列 1 2 0个引物筛选出1 6个引物 ,对 1 0尾蜂巢石斑鱼进行RAPD分析 ,1 6个引物共检测到 1 5 4个位点 ,其中 ,多态位点比例 (P)为 6 5 5 8% ,平均个体间遗传相似系数 (S)为 0 7887,平均个体间遗传距离 (D)为 0 2 1 1 3,遗传多样性指数 (H)为 0 1 776。研究结果表明 ,湛江沿海的野生蜂巢石斑鱼的遗传多样性较高。     

两种体色画眉笛雕的遗传多样性及分子标记

根据体侧纵带颜色差异,暂将画眉笛鲷(Lutjanus vitta)分为黄带画眉笛鲷和褐带画眉笛鲷,应用RAPD技术,选用22个引物对黄带画眉笛鲷与褐带画眉笛鲷进行遗传多样性及分子标记研究。结果表明,黄带画眉笛鲷与褐带画眉笛鲷的遗传距离为0.832 9,其多态位点比例(P)分别为66.99%和85.28%,遗传多样性指数(H)分别为0.161 7和0.289 3,种内遗传距离(D)分别为0.243 5和0.431 9,表明褐带画眉笛鲷的遗传多样性比黄带画眉笛鲷丰富。共得到OPP14-629bp和OPP14-674bp等11个特异性分子标记,可用于两种笛鲷的鉴定。     

Genetic variation of natural and cultured stocks of Paralichthys olivaceus by allozyme and RAPD

Population genetics of the left-eyed flounder, Paralichthys olivaceus, including natural and cultured stocks distributed in the coastal waters near Qingdao of eastern maritime China, was analyzed in allozyme and RAPD. The results showed that among total 29 gene loci of 15 isozymes, 9 and 7 were po- lymorphic in natural and cultured stocks, respectively. The status of genetic diversity in P. olivaceus is low in terms of polymorphic loci in chi-square test and genetic departure index of Hardy-Weinberg equi- librium. More alleles in IDHP, CAT, GDH and Ldh-C allozymes were found in the fish, which could be used as markers in assortive breeding and distinguishing stock, population or species evolution. Total 88 and 86 RAPD bands ranging from 200 to 2 500 bp were recognized individually in average of 7.8–8.0 bands per primer. The genetic diversity in cultured stock is lower than that in natural ones showing an ob- viously decreasing genetic divergence. Therefore, effective countermeasures must be taken to protect ge- netic resources of marine cultured fishes. The 2 markers have their own pros and cons. Combining the 2 markers to investigate the genetic variation of populations is suggested. The results provide basic data of this flounder and they are useful for studying genetic improvement and genetic resources of the fish.     

Genetic diversity in old populations of sessile oak from Calabria assessed by nuclear and chloroplast SSR

In the framework of forest resources conservation, this study aims to understand the dynamic and the genetic structure of sessile oak forests in Calabria, Italy. Two old populations of sessile oak(Quercus petraea(Mattuschka) Liebl.) from two areas of Sila and Aspromonte massifs in Calabria were analyzed for genetic diversity and population structure based on 6 nuclear simple sequence repeat(nSSR) and 4 chloroplastic SSR(cpSSR) loci. The populations displayed high amount of genetic diversity, which was toughly structured according to their geographical origins. Number of alleles at SSR loci ranged from 11 to 20 with an average of 13.5 per locus. Gene diversity(expected heterozygosity, He) estimates ranged from 0.575 to 0.834 with a mean of 0.749. The observed heterozygosity(Ho) was on average 0.458 ranging from 0.150 to 0.682. Polymorphism information content(PIC) values ranged from 0.625 to 0.865 with an average of 0.787. The analysis of molecular variance(AMOVA) highlighted a significant higher estimated variance within populations compared to among populations. Finally, the analysis of haplotypes by using cpSSR suggested a higher diversification in the population from Sila. Hierarchical clustering analysis grouped the genotypes into two major clusters, which agreed with the geographic origin of populations, and was confirmed by the Discriminant Analysis of Principal Components(DAPC). The first cluster included plants/population from Sila massif, while the second encompassed mostly plants/population sampled in Aspromonte massif. Finally, model-based clustering by STRUCTURE analysis also supported the presence of clear genetic structuring in the collection with two major populations(K=2) supported to PCoA analysis as well. Finally, our data indicated the Aspromonte population as a marginal forest with fragmented distribution suggesting different strategies of preservation than in Sila massif.     

GENETIC DIVERSITY OF THE WILD AND REARED PSEUDOSCIAENA CROCEA

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Significant population genetic structure detected in the rock bream Oplegnathus fasciatus(Temminck & Schlegel,1844) inferred from fluorescent-AFLP analysis

Oplegnathus fasciatus(rock bream) is a commercial rocky reef fish species in East Asia that has been considered for aquaculture.We estimated the population genetic diversity and population structure of the species along the coastal waters of China using fluorescent-amplified fragment length polymorphisms technology.Using 53 individuals from three populations and four pairs of selective primers,we amplified 1 264 bands,98.73% of which were polymorphic.The Zhoushan population showed the highest Nei's genetic diversity and Shannon genetic diversity.The results of analysis of molecular variance(AMOVA) showed that 59.55% of genetic variation existed among populations and 40.45% occurred within populations,which indicated that a significant population genetic structure existed in the species.The pairwise fixation index F_(st) ranged from 0.20 to 0.63 and were significant after sequential Bonferroni correction.The topology of an unweighted pair group method with arithmetic mean tree showed two significant genealogical branches corresponding to the sampling locations of North and South China.The AMOVA and STRUCTURE analyses suggested that the O.fasciatus populations examined should comprise two stocks.     

紫红笛鲷随机扩增多态性DNA及遗传多样性分析

采用RAPD技术分析了湛江近海紫红笛鲷 (LutjanusargentimaculatusForsk l)的遗传多样性。从 12 0个随机引物中筛选出了 14个引物。 14个引物共检测到 173个位点 ,其中多态位点比例 (P)为 6 8.79%,遗传距离 (D)为 0 .2 2 2 8,遗传多样性指数 (H)为 0 .190 4。结果表明 ,目前湛江近海的紫红笛鲷自然群体的遗传多样性仍然维持在良好水平 ,捕捞尚未对其造成明显影响。     

The mycobiota of discoloured needles of the Swiss stone pine (<Emphasis Type="Italic">Pinus cembra</Emphasis> L.) in the Tatra Mountains (Poland)

The Swiss stone Pine (Pinus cembra L.) is an alpine species, fairly commonly occurring in the Alps and the Carpathians, close to the timberline. Natural sites of the Swiss stone pine in Poland are found exclusively in the Tatra Mountains, within the area of the Tatra National Park (TNP). In 2017, the health status of the needles of P. cembra was determined and their mycological analysis was carried out. As a result, 11 species of fungi were isolated from the needles showing disease symptoms, manifested by various shades of discoloration. The most frequently observed species was Fusarium oxysporum. It probably does not bring on disease symptoms, but may affect the development of other frequently isolated species (such as Sydowia polyspora, Lophodermium sp. and Lophodermium conigenum) that are pathogenic to Pinus spp.     

Genetic diversity of populations and clones of Rhopilema esculentum in China based on AFLP analysis

Amplified fragment length polymorphisms(AFLP) markers were developed to assess the genetic variation of populations and clones of Rhopilema esculentum Kishinouye(Scyphozoa,Rhizostomatidae).One hundred and seventy-nine loci from 56 individuals of two hatchery populations and two wild populations were genotyped with five primer combinations.The polymorphic ratio,Shannon’s diversity index and average heterozygosity were 70.3%,0.346 and 0.228 for the white hatchery population,74.3%,0.313,and 0.201 for the red hatchery population,79.3%,0.349,and 0.224 for the Jiangsu wild population,and 74.9%,0.328 and 0.210 for the Penglai wild population,respectively.Thus,all populations had a relatively high level of genetic diversity.A specific band was identified that could separate the white from the red hatchery population.There was 84.85% genetic differentiation within populations.Individual cluster analysis using unweighted pair-group method with arithmetic mean(UPGMA) suggested that hatchery populations and wild populations could be divided.For the hatchery populations,the white and red populations clustered separately;however,for the wild populations,Penglai and Jiangsu populations clustered together.The genetic diversity at the clone level was also determined.Our data suggest that there are relatively high genetic diversities within populations but low genetic differentiation between populations,which may be related to the long-term use of germplasm resources from Jiangsu Province for artificial seeding and releasing.These findings will benefit the artificial seeding and conservation of the germplasm resources.