Assessing genetic diversity of wild populations of Japanese flounderusing AFLP markers

Amplified fragment length polymorphism （AFLP） analysis was used to evaluate the genetic diversity of four wild geographical populations of Japanese flounder （Paralichthys olivaceus）. A total of 775 loci （58.32% of which was polymorphic） in the range between 100 and 1 300 base pairs were detected from 110 individuals using seven primer combinations. The percentage of polymorphic loci detected by single primer combination for each population was calculated, ranging from 19.59% to 53.33%. Genetic similarities within and among the populations were calculated from the binary matrices of presence - absence. Phylogenetic tree of four populations was constructed by using the UPGMA method using PHYLIP Version 3.5. According to intrapopulation genetic similarities, CW population displayed the highest genetic diversity value and KY population had the lowest genetic diversity value. The distance between CW and CF populations was the farthest, which was possibly resulted from the farthest distance of Weihai of Shandong and Fujian of China compared with the geographical distance between other locations of populations. The subpopulation differentiation value （G.,） is 0. 356 5, showing a certain extent of differentiation among the four geographical populations. AFLP technology was confirmed to be an effective tool to assess within- and among-population genetic diversity of Japanese flounder. The present survey provided significant insights for research in the Japanese flounder breeding program.

AFLP analysis revealed differences in genetic diversity of four natural populations of Manila clam (Ruditapes philippinarum) in China

The amplified fragment length polymorphism （AFLP） technology was used to analyze the genetic diversities in four natural populations of Manila clam （ Ruditapes philippinarum）, distributed in four sea areas of China, i.e. , the Bohai Sea, the Huanghai Sea, the East China Sea and the South China Sea. Two hundred and sixty-four AFLP loci were analysed in 195 individuals and revealed high levels of genetic diversity. The percentage of polymorphic loci ranged from 92.13% to 96.06% and the Shannon＇ s information index was from 0.256 8 to 0. 275 6. By analyzing molecular variance （ AMOVA）, it was found that there were high levels of genetic differentiation between populations of Qingdao and the other three sea areas. Cluster analysis by Nei＇ s pairwise distances grouped specimens by geographical origin, except the population of Qingdao. A conclusion can be drawn that there are high genetic diversities in the four natural populations of Manila clam in China and some distinct differences existed among and between the four populations. The results also indicated that human cultivation activities will have great influence on the genetic structure of the population of Qingdao.

Genetic Diversity Analysis of Cultured Populations of Jade Perch （Scortum bacoo） in China Using AFLP Markers

Genetic diversity of three cultured populations of jade perch （Scortum bacoo） are studied using amplified fragment length polymorphism （AFLP） markers, which is Guangzhou（GZ） population, Foshan （FS） population and Qingdao（QD） population. Nine primer combinations were used and 385 fragments were detected. Among the 385 fragments, 80 bands （20.78%） were polymorphic. And it can be speculated that the genetic diversity of the three cultured populations of jade perch was very poor according to the gene genetic diversity among populations （Ht）, the gene genetic diversity within populations （Hs） and Shannon-Weiner index （I）. From gene differentiation （Gst）, genetic distance （D）, genetic similarity （5）, and UPGMA analysis, it is found that the relationship among the three populations is very closed, and the difference in genetic diversity among the three populations is not significant. Further clustering relationships of the jade perch cultured populations also are correlated to historical-breeding observations and genetic relationships. The GZ population clustered together with the QD population first, then with FS population.

Genetic diversity and population structure of 288 potato(Solanum tuberosum L.) germplasms revealed by SSR and AFLP markers

Potato （Solanum tuberosum L.） is an important staple food and economic crop in many countries. China has led world potato production in recent years. To understand the genetic diversity of potato germplasms and to enrich the current gene pool for potato improvement, we made a global collection consisted of 288 potato germplasms from eight countries and the International Potato Center （CIP）. Using SSR and AFLP techniques, we evaluated the genetic diversity and population structure of these 288 potato accessions. A total of 190 alleles on 20 SSR loci were detected and all of the SSR alleles were polymorphic among these potato germplasms with an average of 9.5 alleles per SSR locus ranging from 2 to 23. The effective number of alleles per locus （Ne＊）, Nei＇s genetic diversity （H＊）, and Shannon＇s information index （I＊） was from （0.1709＋0.3698） to （1.6166＋0.3414）, （0.076＋0.1388） to （0.3812＋0.1886）, and （0.1324＋0.1970） to （0.5347＋0.1440）, respec- tively, and the mean polymorphic information content （PIC） value was 0.7312. A total of 988 AFLP alleles were detected by 10 AFLP primer combinations with 983 polymorphic alleles, and 99.49% alleles was polymorphic with an average of 98.3 polymorphic alleles per primer combination ranging from 91 to 116. The values of Ne＊, H＊ and/＊ were from （1.5162＋0.311 ） to （1.6423＋0.3278）, （0.3114＋0.145） to （0.3675＋0.1121）, and （0.4761＋0.1792） to （0.547＋0.1322）, respectively, and the average PIC value was 0.9871. Bayesian analysis discriminated the accessions into seven subgroup and an admix group. The majority of accessions from CIP and China were assigned into SG1, SG5, SG6, SG7 and admix group. Accessions in SG3 were mainly from CIP and two small groups SG2 and SG4 were mainly from northeastern China. In general, the results obtained from Bayesian statistical analysis, cluster analysis and principal coordinate analysis consistently revealed the lack of geographical differentiation among country-wide collections, indicating germplasm introduction was common for the countries out of potato origin center. The poiymorphic markers and the differentiate genetic lineages found in this study provide useful information for potato improvement and conservation programs.

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.

Detection of Adaptive Genetic Diversity in Wild Potato Populations and Its Implications in Conservation of Potato Germplasm

A better understanding on how genetic diversity is structured at natural habitats can be helpful for exploration and acquisition of plant germplasm. Historically, studies have relied on DNA markers to elucidate potato genetic diversity. Current advances in genomics are broadening applications allowing the identification of markers linked to genomic regions under selection. Those markers, known as adaptive markers, unlock additional ways to value and organize germplasm diversity. For example, conservation priorities could be given to germplasm units containing markers associated to unique geographic identity, and/or linked to traits of tolerance to abiotic stresses. This study investigated if adaptive marker loci were possible to be identified in a large AFLP marker dataset of ninety-four populations of the wild potato species S. fendleri. These populations originated from six different mountain ranges in southern Arizona, USA. A total of 2094 polymorphic AFLP markers were used to conduct genetic diversity analyses of populations and mountain ranges. Adaptive markers were detected using Bayesian methods which distinguished marker loci departing significantly from frequencies expected under neutral models of genetic differentiation. This identified 16 AFLP loci that were considered to be adaptive. To contrast diversity parameters generated with each set of markers, analyses that included all the 2094 AFLP markers, and only the 16 adaptive markers were conducted. The results showed that both were efficient for establishing genetic associations among populations and mountain ranges. However, adaptive markers were better on revealing geographic patterns and identity which would suggest these markers were linked to selection at the natural sites. An additional test to determine if adaptive markers associated to climate variables found two loci associated to specific climate variables in populations from different regions but sharing similar environmental structure. The distribution of adaptive markers among populations revealed that only two were needed to build a core subset able to keep all the markers. This preliminary assessment shows that adaptive genetic diversity could offer an additional way to measure diversity in potato germplasm and to set up options for conservation and research.

Population Genetic Diversity in Chinese Pomegranate (Punica granatum L.) Cultivars Revealed by Fluorescent-AFLP Markers

Eighty-five pomegranate （Punica granatum L.） cultivars from six geographical populations located at Shandong, Anhui, Shaanxi, Henan, Yunnan, and Xinjiang Provinces were studied for its population genetic diversity by means of fluorescent-AFLP markers. The results indicated that 135-185 polymorphic loci were amplified by eight pairs of primers at species level. An average of 158.25 polymorphic loci was amplified for each primer combination. The polymorphism percentage ranged from 62.5% to 86.11%, and the average polymorphism percentage was 73.26%. This indicated that there was plentiful genetic diversity in pomegranate cultivars. The genetic diversity at the species level was higher than that at the population level. The order of the genetic diversity was Henan population 〉 Xinjiang population 〉 Shaanxi population 〉 Anhui population 〉 Shandong population 〉 Yunnan population. Variance analysis showed that there was significant difference between populations in genetic diversity. The genetic differentiation coefficient between populations （Gsr） was 0.2018, which indicated that gene differentiation was mainly within the population, and between populations, it accounted for 20.18% of the total variation. Gene flow （Nm） between the populations measured was 1.9027 based on the genetic differentiation coefficient between populations, indicating that there was mild gene flow between populations. The UPGMA cluster analysis showed that most accessions from the same population were clustered together, but there was partly gene exchange. All genetic parameters indicated that there was plentiful genetic diversity in pomegranate cultivars in China, of which Henan population was significantly higher than the other populations, and it had wide application foreground in pomegranate breeding in China.

四个鲤鱼种群遗传多样性的AFLP分析

本文采用AFLP技术对黑龙江野鲤、黄河鲤、建鲤和荷包红鲤4个鲤鱼种群共96个个体进行了遗传多样性分析。结果显示,8对选择性扩增引物共扩增得到502个位点,其中多态性位点273个,多态性比率为54.38%。同时对4个种群的Shannon多样性指数,Nei's基因多样性等参数进行了分析,结果表明,4个种群的Shannon多样性指数分别为0.2114±0.2705,0.1825±0.2694,0.1888±0.2587和0.1600±0.2426,Nei's基因多样性指数分别为0.1398±0.1872,0.1225±0.1863,0.1235±0.1774和0.1036±0.1636;总基因多样性(Ht)平均值为0.1721±0.0350;种群内基因多样性(Hs)平均值为0.1224±0.0190;基因分化系数(Gst)为0.2892,种群内的基因多样性占总群体的71.08%,种群间为28.92%,而基因流系数(Nm)为1.2291。另一方面,分子方差分析(AMOVA)结果表明,种群平均近交系数(Fst)为0.31191,变异31.19%来自种群间,68.81%来自种群内。4个种群中黑龙江野鲤的种内多态性比例最高,而荷包红鲤种群最低,并且4个鲤鱼种群当前的种质资源良好,具有一定的种群稳定性;建鲤已经开始分化,与亲本荷包红鲤亲缘关系逐渐分化,逐步形成自己稳定的遗传结构。本研究为探讨鲤鱼种群的遗传特性和遗传分化提供参考,也为其种质资源的保护及合理利用提供科学依据。

基于形态参数和AFLP标记的文蛤(Meretrix meretrix)不同地理群体遗传变异分析

应用方差分析和Tukey多重比较对文蛤的辽宁(LN)、山东(SD)、江苏(JS)、广西(GX)4个自然地理群体的7个壳形态参数进行了研究,结果发现,SD和JS群体间差异不显著,LN和GX群体差异不显著,GX群体与SD和JS群体间差异显著(P<0.05)。利用4对引物组合对这4个群体进行了AFLP扩增,共得到236个位点,其中特有位点14个,这些特有位点可作为群体鉴别的特征性标记。遗传多样性分析表明,4个文蛤群体的遗传多样性水平均较高,而以GX群体最高,Nei’s基因多样性指数和Shannon’s多样性指数分别达到0.2636、0.3961,SD群体最低,分别为0.2308、0.3462。从群体间遗传距离和NJ法构建的亲缘关系谱系图来看,LN和SD群体的遗传距离最近(0.0394),首先聚在一起,而GX群体与其他3个群体间都较远(0.1271—0.1586),单独分出一支,这说明GX群体已发生了明显的遗传分化,用它与其他3个群体杂交可望较大幅度地提高遗传多样性水平。

用AFLP技术分析四川核桃资源的遗传多样性

利用AFLP分子标记技术,运用EcoRⅠ/MseⅠ双酶切组合,选用多态性高、分辨力强的4对选择性扩增引物组合E32/M48、E33/M61、E35/M61、E33/M62分别对四川省3个野生核桃(Juglansregia)种群和1个野生铁核桃(J.sigillata)种群共46个样品进行遗传多样性分析、居群遗传结构分析及种属关系探讨。结果表明:1)共扩增出244个遗传位点,其中146个多态位点,多态率为59.84%;核桃群体组和铁核桃群体的多态性百分率分别为55.33%和52.05%,两个物种遗传多态性水平相当;核桃群体组所检出的位点平均有效等位基因数Ae、Nei’s基因多样度H、平均Shannon信息指数I分别为1.3229、0.1908和0.2863,而铁核桃群体分别为1.3399、0.1961和0.2898,铁核桃群体遗传多样性水平略高于核桃群体。2)群体间特异带及群体间共有带占总扩增带数的15.16%,其中铁核桃群体特异谱带最多,群体特异谱带揭示了群体间的遗传差异及相似性。3)Shannon信息指数(I)、Nei’s基因多样性指数(H)和分子方差分析(AMOVA)表明核桃遗传多样性在群体间和群体内的分布分别为14.36%和85.64%、12.6%和87.4%、11.07%和88.93%,表明群体内的遗传多样性大于群体间的遗传多样性;核桃群体组与铁核桃群体的变异主要存在于群体组内,组间的遗传变异仅占总变异的9.35%,两者间的遗传分化系数Gst为0.0935,与AMOVA分析结果一致。4)4个群体的Nei’s遗传距离在0.0382～0.0692之间,遗传一致度在0.9332～0.9625之间,表现出较高的遗传相似性;运用Nei’s遗传一致度对供试种群进行了UPGMA聚类,结果表明核桃的3个群体优先聚类,大渡河流域群体与甘南地区群体聚类最近。AFLP所检测出的结果既是核桃与铁核桃生物学特性的反映,又是其各自生态学特性的反映,该研究结果对核桃种质资源的保护和育种提供一定的理论依据。

普通杏群体遗传结构的荧光AFLP分析

以准噶尔—伊犁生态群(新疆野杏)、中亚生态群(新疆栽培杏和李光杏)、欧洲生态群和华北生态群的45个普通杏品种或材料为试材,以梅杏、辽梅杏和辽杏为外组,利用荧光AFLP标记对普通杏4个生态群的群体遗传结构进行了研究,结果表明:7对EcoRⅠ/MseⅠ引物(其中MseⅠ引物为FAM荧光标记物)平均扩增多态带数为130.86,平均多态带百分比为60.58%。4个生态群的多态带百分比比较表明:准噶尔—伊犁新疆野杏生态群(P=43.59%)>中亚南疆栽培杏生态群(P=41.27%)>华北生态群(P=39.42%)>欧洲生态群(P=39.42%)>中亚李光杏生态群(P=37.57%);普通杏在种级水平Neis基因多样度(H=0.143)和Shannon信息指数(I=0.226)显著或极显著高于群体水平。在群体水平上,准噶尔—伊犁新疆野杏生态群的Neis基因多样度和Shannon信息指数(H=0.131;I=0.202)高于中亚生态群(南疆栽培杏)(H=0.127;I=0.195)、欧洲生态群(H=0.124;I=0.189)和华北生态群(H=0.116;I=0.180),但无显著性差异,显著高于中亚李光杏生态群(H=0.113;I=0.173);普通杏4个生态群的遗传分化系数(GST=0.147)显示,普通杏的遗传变异主要存在于群体内,占总变异的85.3%;通过遗传分化系数计算得GST基因流Nm=2.901,说明普通杏4个生态群存在适度的基因交流,人为引种可能是产生基因交流的主要原因,而地理隔离可能是阻碍基因交流的主要因素。对普通杏4个生态群的群体遗传多样性和群体遗传结构的分析初步认为,普通杏起源于准噶尔—伊犁新疆野杏生态群,通过人为驯化,在新疆南部形成栽培杏中心,并形成中亚南疆栽培杏生态群,之后通过人为引种向东传播形成华北生态群,向西传播形成欧洲生态群。

蒙古栎天然群体遗传多样性的AFLP分析

以黑龙江省小兴安岭嘉荫、内蒙古大青沟和河北省雾灵山的 3个蒙古栎群体及北京东灵山辽东栎群体为供试材料 ,用筛选出的 4对荧光引物 ,对 4个群体共计 96个个体进行AFLP分析 ,每对AFLP引物扩增出 6 3～ 1 1 3条 ,共得到 346条多态带 ;群体特异带及群体间共有带的差异与分布揭示了群体间的遗传差异及相似性 ;蒙古栎遗传多样性主要存在于群体内 ,群体间的遗传分化系数Gst为 0 0 77。蒙古栎在种级水平的遗传多样性参数略高于群体水平 ,多态带百分率P分别为 96 8%、6 7 2 % ,有效等位基因数Ae分别为 1 2 2 0、1 2 0 8,Nei基因多样性指数H分别为 0 1 4 5、0 1 34,Shannon多样性指数I分别为 0 2 4 6、0 2 0 8。东灵山辽东栎群体的P为 6 7 6 % ,Shannon多样性指数I为 0 2 2 0 ,Nei基因多样性指数H为 0 1 34。UPGMA聚类分析结果表明 ,蒙古栎自然群体间的遗传距离有随地理距离跨度增加而递增的趋势。蒙古栎遗传多样性偏低可能与其在历史上长期用作经济树种、人为干预和环境破坏较为严重。

甘草野生种群遗传多样性的AFLP分析

【目的】甘草具有重要的药用、工业和生态价值,目前处于濒危状态,进行遗传多样性研究可以为甘草资源的保护和利用奠定基础。【方法】利用AFLP分子标记对来自中国甘草主产区的16个野生种群共320个单株进行遗传多样性研究。【结果】(1)利用15对AFLP引物共扩增出759条谱带,其中多态性谱带527条,多态性条带百分率为69.43%;(2)Nei’基因多样性指数为0.13～0.19,种群总体多样性指数为0.25;Shannon多态性信息指数的变异范围在0.19～0.28,总体为0.39;宁夏地区甘草种群遗传多样性水平最高,甘肃酒泉种群的遗传多样性水平最低。(3)AMOVA分析表明甘草种群间的遗传变异占总变异的18.64%,种群内变异占67.16%。利用UPGMA聚类可将供试16个群体划分为3类,聚类结果表现出明显的地域性。【结论】该研究明确了中国野生甘草遗传多样性处于中等偏下水平,种群内广泛的变异能够为野生资源保护和良种选育提供理论依据。

管角螺遗传多样性的AFLP分析

近年来,由于对管角螺的捕捞强度加大,其自然资源大大减少。为进一步了解管角螺的遗传变异和群体结构状况,本文首次利用AFLP(Amplified fragment length polymorphism,扩增片段长度多态性)分子标记技术对我国南方沿海管角螺5个地理群体(连云港、温州、台山、湛江、防城港)进行遗传多样性分析。采用2对AFLP引物组合对管角螺5个群体的150个个体进行扩增,共扩增出310个位点,多态位点277个,多态位点比例为89.35%,基因多态性分别为0.382 4、0.476 6、0.393 8、0.437 4和0.392 8,说明5个群体的遗传多样性存在一定的差异。群体间及群体内遗传分化指数表明,管角螺5个地理群体的遗传变异主要来自于群体内个体间,而群体间无明显的遗传分化。UPGMA(非加权组对平均法)系统树分析表明,湛江和防城港群体间的亲缘关系较近,而台山和温州群体间的亲缘关系较远。

应用AFLP技术分析多鳞四指马鲅不同地理群体的遗传多样性

为研究多鳞四指马鲅(Eleutheronema rhadinum)不同地理群体的遗传多样性,应用AFLP技术分析了江苏东南部近海海域(QD)、广东湛江近海海域(ZJ)、上海崇明长江口附近水域(CM)和海南琼海近海海域(QH)4个地理群体的遗传特征和群体分化。120 ind个体样品、8对引物组合共扩增246条带,多态性条带为128条,多态性比例为53.4%。群体ZJ扩增位点最多,多态性比例也最高,群体内的Nei’s基因多样性指数和Shannon’s信息指数变化趋势一致,均为CM<QD<QH<ZJ。应用AMOVA对4个群体的遗传变异来源进行分析得出,总的遗传分化指数Fst为0.101 2,表明9.12%的变异来自于群体间,90.88%的变异来自于群体内个体间,说明群体之间已发生了一定程度的遗传分化。聚类分析表明,各群体间的遗传相似性系数在0.891 8～0.928 7之间,遗传距离在0.073 9～0.114 5之间,其中群体ZJ和群体QH间的遗传距离最近,为0.073 9。

秦巴山区野板栗居群遗传多样性AFLP分析

利用荧光AFLP标记技术对来自秦巴山区的野板栗10个居群共262个单株进行遗传多样性研究。10对AFLP引物共扩增出1297条谱带,其中多态性位点数1011个,多态位点百分率为77.95%;Ne′is基因多样性指数为0.1439~0.2046,总体为0.2518;Shannon信息指数的变异范围为0.1972~0.2895,总体为0.4089;甘肃地区野板栗居群遗传多样性水平最高,陕西宝鸡居群的遗传多样性水平最低。AMOVA分析表明野板栗居群间的遗传变异占总变异的17.51%,居群内变异占69.76%。UPGMA聚类可将供试10个居群划分为3类,聚类结果表现出明显的地域性。

基于120K液相芯片对310份小麦种质的遗传多样性分析

为了解贵州小麦农家种与其他地方育成品种间基因组中被选择的区域,对来自中国黄淮麦区和西南麦区的310份小麦材料进行了120K液相芯片检测。结果表明,该群体可以分为中国北方、中国南方和贵州农家种3个相对独立的类群,其中四川的小麦遗传多样性相对较高,贵州农家种遗传多样性较低。其原因可能是四川小麦含有一定的阿勃血统和人工合成小麦的血缘,对小麦的增产增收具有突出作用,而贵州农家种在现代育种中使用频率很低。陕西的小麦品种在第一、第三和第五亚群中,可能是陕西当地的材料引进了其他地方的小麦种质资源,通过杂交或者回交产生了新的品种(系),血缘上更加丰富,遗传多样性更高。通过对贵州农家种/其他地方育成品种(系)之间选择性消除分析,利用π、Fst、XP-CLR等方法鉴定到与春化、株高、芒长、抗病、抗逆等相关的37个基因,包括了诸如TaVRN2-5A、TaDIR-A1、Rht12和ALI-1/B1/Tipped1/AWNS1等的重要位点。由此可见,中国部分育成小麦品种存在遗传多样性差异,建议通过开发新的育种策略,聚合优异等位基因,促进对地方农家种合理利用。

舟山近海条石鲷野生群体与人工放流群体遗传多样性的AFLP分析

利用AFLP技术对舟山近海条石鲷(Oplegnathus fasciatus)野生和放流群体的遗传多样性进行比较分析,旨在为条石鲷的人工增殖及其种质资源的保护和利用提供遗传学的基础资料。采用8对引物组合在2个群体中共扩增得到位点316个,多态性位点为162个,多态性比例为51.67%。野生群体和放流群体的多态性位点比例(P),Nei’s基因多样性指数(H)和Shannon’s多样性指数(I)分别为46.75%和44.67%,0.097和0.089,0.16和0.15。野生群体的遗传多样性水平略高于放流群体,但差异并不显著(P>0.05)。两群体间的遗传相似系数(S)和遗传距离(D)分别为0.99和0.0073;基因分化系数(Gst)为0.036,群体间无显著遗传分化(P>0.05)。分子方差(AMOVA)分析表明96.82%的遗传变异来源于群体内的个体间,群体间无显著的遗传差异(P>0.05)。以上研究结果表明条石鲷的放流群体与野生群体间无明显的遗传分化,放流群体的遗传多样性水平尚处于一个合理状态。但为了避免放流群体对野生群体产生负面的遗传效应,应当增加放流群体繁育亲本的数量,并对放流群体的遗传变异水平进行持续监测。

西藏地区雪层杜鹃遗传多样性的AFLP分析

采用AFLP技术对西藏地区雪层杜鹃(Rhododendron nivale)5个天然种群135份材料进行遗传多样性和遗传分化研究。筛选得出的6对引物共扩增产物273条DNA片段,扩增多态位点百分率为85.71%。5个雪层杜鹃种群的遗传多样性指标表现了相似的变化趋势,Nei基因多样性指数(h)和Shannon信息指数(I)的变化趋势一致,均为工布江达县种群<米林种群<嘎隆拉种群<色季拉山种群<红拉山种群。POPGENE分析结果表明雪层杜鹃在物种水平(PPL=85.71%,I=0.415 1,h=0.273)具有较高的遗传多样性,种群水平(PPL=62.26%,I=0.280 3,h=0.184 1)的遗传多样性较低。AMOVA分析结果表明36%的遗传变异存在于种群间,64%的遗传变异存在于种群内,雪层杜鹃种群间的遗传分化系数(G_(st)=0.324)与AMOVA分析得到的遗传变异分布结果一致。UPGMA聚类结果说明雪层杜鹃的遗传距离与地理距离和海拔高度没有明显的相关性。综合分析,引起雪层杜鹃的遗传变异的原因可能是地理环境不同和种群的生境类型差异。最后就雪层杜鹃的合理开发和保护提出建议。

长江合江江段岩原鲤种群遗传多样性的AFLP分析

用9对引物对采自长江上游合江江段的岩原鲤种群的14个个体进行了选择性扩增片段长度多态性研究,共检测出AFLP位点755个,平均每对引物扩增出84个位点,其中多态性位点354个,占46.89%.个体间的遗传距离为0.1061～0.2846,平均遗传距离为0.1793±0.0337.种群平均杂合度为0.1768.与其它一些鱼类比较表明,岩原鲤长江合江种群的遗传多样性可能不够丰富.