Microsatellite markers uncover cryptic species of Odontotermes (Termitoidae: Termitidae) from Peninsular Malaysia

Termites from the genus Odontotermes are known to contain numerous species complexes that are difficult to tell apart morphologically or with mitochondrial DNA sequences. We developed markers for one such cryptic species complex, that is, Odontotermes srinakarinensis sp. nov. from Maxwell Hill Forest Reserve (Perak, Malaysia), and characterised them using a sample of 41 termite workers from three voucher samples from the same area. We then genotyped 150 termite individuals from 23 voucher samples/colonies of this species complex from several sites in Peninsular Malaysia. We analysed their population by constructing dendograms from the proportion of shared-alleles between individuals and genetic distances between colonies; additionally, we examined the Bayesian clustering pattern of their genotype data. All methods of analysis indicated that there were two distinct clusters within our data set. After the morphologies of specimens from each cluster were reexamined, we were able to separate the two species morphologically and found that a single diagnostic character found on the mandibles of its soldiers could be used to separate the two species quite accurately. The additional species in the clade was identified as Odontotermes denticulatus after it was matched to type specimens at the NHM London and Cambridge Museum of Zoology.     

不同地域野生欧李及其近缘植物亲缘关系的RAPD分析

利用RAPD分子标记技术对21个不同地域欧李及其近缘种属植物(桃、杏、李、樱桃)进行了遗传亲缘关系及分类研究。结果表明,用于不同地域野生欧李分析的25条引物中,共扩增出441个清晰可用的DNA片段,其中多态性位点366个,多态性比为82.99%。在遗传相似系数为0.71时,可将中国野生欧李资源划分为3个大的区域,分别为东北分布群、华北华东分布群与中西部分布群。用于欧李及其近缘种属植物分析的20条引物中,共扩出多态性带683条,多态性比率为98.99%。聚类分析表明,在遗传相似系数为0.61时,欧李与其近缘种属植物分为3大类;欧李与麦李的亲缘关系最近,与桃亲缘关系最远。     

稻瘟病菌群体的分子遗传学研究II.广东省2000年度稻瘟病菌群体遗传结构的时空特性

利用随机扩增多态性DNA技术对广东省2000年度稻瘟病菌群体的遗传结构进行了分析。以相似性系数为0.62阀值时,可将采集于广东省三大生态稻作区、早稻和晚稻生长季节的104个菌株划分为14个遗传宗谱;其中宗谱5和宗谱8的菌株数各占总数的25%,为优势宗谱;宗谱4和12的菌株数各占总数的14.4%和9.6%,为亚优势宗谱;其余的29个菌株,分别归属于其它10个宗谱,其中有5个宗谱是单菌株宗谱。本年度稻瘟病菌群体的遗传结构呈现明显的区域性特性:遗传结构呈由北向南多样化的趋势;各个稻作区甚或亚区有其特异性的宗谱。本年度稻瘟病菌群体的遗传结构也显示分明的生长季节特性:来源于早稻和晚稻生长季节的菌株完全分属于宗谱图的上下两个半区,彼此之间不存在共同的宗谱;而且后者的遗传宗谱要比前者的复杂、多样。研究还表明,虽然稻瘟病菌群体的遗传结构2000年度与1998-1999年度的比较存在较大的差异,但是两者仍然具有良好的相承性和可比性。如何进一步验证和把握稻瘟病菌群体的遗传结构所表现出的时空特性是值得我们进一步探讨的重要课题。     

沙田柚系列遗传关系的RAPD标记研究

采用 RAPD标记技术分析了沙田柚系列 1 2个样品的遗传关系。利用经筛选具多态性的 1 4个 1 0碱基随机引物对 1 2个样品进行 DNA随机扩增 ,获得清晰可重复的位点 99个 ,其中多态性位点 5 8个 ,占 5 8.89% ;在部分样品中检出了特异性 RAPD标记 1 9个 ,占 1 9.1 9% ;通过样品间遗传相似性系数比较与 UPGMA聚类分析 ,并根据历史事实可知 ,广西沙田柚、梅州金柚为沙田柚的无性繁殖系 ,软枝系沙田柚、沙田柚早熟单株为沙田柚的芽变后代 ,梅花早柚、菊花心沙田柚、冬瓜圈沙田柚、段氏柚、垫江沙田柚、古老钱沙田柚为沙田柚的实生变异品系。     

地黄属和崖白菜属的数量分类

选择地黄属Rehmannia和崖白菜属Triaenophora的8种植物55个形态学、细胞学、花粉学等性状指标, 根据种间欧氏距离, 利用NTSYS-pc Version 2.10e 软件中的UPGMA聚类分析方法和主成分分析方法, 首次对这两个属进行数值分类学研究。结果表明: 地黄属与崖白菜属是两个自然类群, 除地黄属内的高地黄与裂叶地黄在UPGMA聚类中不能分开外, 其他物种都能很好地分开。数量分类支持最近新发表的神农架崖白菜新种。     

稻瘟病菌群体的分子遗传学研究Ⅲ.广东省2001年度稻瘟病菌群体的遗传结构分析以及两个假说的提出

利用随机扩增多态性DNA技术 (random amplified polymorphic DNA, RAPD) 对广东省2001年度稻瘟病菌群体的遗传结构进行了分析.以相似性系数为0.70阈值时,可将采集于广东省三大生态稻作区、早稻和晚稻生长季节的96个菌株划分为12个遗传宗谱; 其中宗谱8和9的菌株数各占总数的25% 和18.8%,为优势宗谱.从稻作区来看,宗谱3 和 8为各个稻作区的共同宗谱;而宗谱1和 2,7和11,以及9、10和12则依次是粤北、粤中和粤南稻作区的特异性宗谱.从生长季节来看,来源于早、晚季的菌株完全分属于宗谱图的上、下两个半区,彼此之间不存在共同的宗谱;而且两个优势宗谱都集中于晚季供试亚群体.结合前两次实验的结果,作者提出了如下两个假说来解释广东省稻瘟病菌群体所表现的遗传特性一个地区或生长季节的病原菌群体,其优势宗谱所占的比例越高,该地区或生长季节病害发生就越严重;在长期的水稻栽培历史中,稻瘟病菌群体可能逐步地形成了早季宗谱(小种)和晚季宗谱(小种)的遗传分化.如何进一步验证上述两个假说是值得我们进一步探讨的重要课题.     

利用SRAP标记分析河南小麦栽培品种的遗传多样性

利用小麦SRAP标记对22个河南省小麦品种进行了遗传多样性分析,10对引物组合扩增获得169个条带,其中70个条带具有多态性,多态条带百分率为41．42％,每对引物平均产生7个多态性条带。22个供试材料的带型按照条带的有、无分别记录为1、0后,采用Nei72方法计算不同品种的遗传距离,利用NTSYS软件进行非加权组法（UPGMA）聚类分析。结果表明SRAP标记技术能较真实地反映小麦品种间的亲缘关系,可以用于小麦品种遗传多样性研究。     

卫矛科沟瓣属与卫矛属的数量分类学研究

卫矛属(Euonymus L.)和沟瓣属(Glyptopetalum Thw.)的系统关系长期以来备受争议,为理清它们之间的关系,该研究选择沟瓣属12种、卫矛属17种和假卫矛属(Microtropis Wall. ex Meisn.)2种,共计31个分类单元(OTUs),测量并统计了56个形态性状,同时利用聚类分析(UPGMA)和主坐标分析(PCoA)的方法进行了数量分类学研究。结果表明:沟瓣属与卫矛属具有较高的表征相似性,二者之间存在的过渡类群有缙云卫矛(Euonymus chloranthoides Yang)和淡绿叶卫矛(E. pallidifolium Hayata)以及海南沟瓣 [Glyptopetalum fengii (Chun & F. C. How)Ding Hou]、白树沟瓣 [G. geloniifolium(Chun & F. C. How)C. Y. Cheng]。该研究认为将沟瓣属作为卫矛属的一个组,即沟瓣组(Sect. Glyptopetalum),放在冬青卫矛组(Sect. Ilicifolia)附近更为合理。对性状的主坐标排序分析显示,叶片长度、叶片宽度、叶侧脉数目、花瓣数目、心室数目、每室胚珠数、花序分枝数、是否具有假种皮、蒴果是否开裂、花期与果序梗长度在卫矛属分类中具有重要的价值。     

Comparative analysis of DNA polymorphisms and phylogenetic relationships among Syzygium cumini Skeels based on phenotypic characters and RAPD technique

The Indian black berry (Syzygium cumini Skeels) has a great nutraceutical and medicinal properties. As in other fruit crops, the fruit characteristics are important attributes for differentiation were also determined for different accessions of S. cumini. The fruit weight, length, breadth, length: breadth ratio, pulp weight, pulp content, seed weight and pulp: seed ratio significantly varied in different accessions. Molecular characterization was carried out using PCR based RAPD technique. Out of 80 RAPD primers, only 18 primers produced stable polymorphisms that were used to examine the phylogenetic relationship. A sum of 207 loci were generated out of which 201 loci found polymorphic. The average genetic dissimilarity was 97 per cent among jamun accessions. The phylogenetic relationship was also determined by principal coordinates analysis (PCoA) that explained 46.95 per cent cumulative variance. The two-dimensional PCoA analysis showed grouping of the different accessions that were plotted into four sub-plots, representing clustering of accessions. The UPGMA (r = 0.967) and NJ (r = 0.987) dendrogram constructed based on the dissimilarity matrix revealed a good degree of fit with the cophenetic correlation value. The dendrogram grouped the accessions into three main clusters according to their eco-geographical regions which given useful insight into their phylogenetic relationships.