Significant population structure in Australian Cryptolestes ferrugineus and interpreting the potential spread of phosphine resistance

An analysis of the population genetics of Cryptolestes ferrugineus, across all major regions in Australia where grain is grown and stored in bulk, provides an initial step in investigating the movement of these insects and implications for the spread of phosphine resistance. Microsatellite data revealed two levels of genetic structure. Across Australia, two clusters were detected, one in eastern Australia (Queensland, New South Wales, Victoria and Tasmania) and Western Australia (Cluster 1) and one in South Australia (Cluster 2). Intermediate between them, in eastern South Australia, are a couple of populations that are equally admixed for the two clusters. Populations in Western Australia and western SA belong to different clusters suggesting that the extensive and arid Nullarbor Plain restricts the natural dispersal of these beetles. Isolation-by-distance and the detection of clustering among local populations suggests there is considerable gene flow at a local scale in C. ferrugineus, and we infer this is by flight. Limited natural gene flow between eastern and western Australia might, in part, explain why extremely high resistance has not been detected in Western Australia.     

Development of microsatellite markers and a preliminary assessment of population structuring in the rice weevil,Sitophilus oryzae (L.)

The rice weevil, Sitophilus oryzae is one of the primary pests of stored grains worldwide. To develop and implement an effective integrated pest management strategy, an understanding of the population structuring of this destructive pest is vital. In this study we used Illumina paired-end sequencing to develop S. oryzae species-specific microsatellite markers, and used these markers to conduct a preliminary assessment of population structuring in four populations of S. oryzae from three countries (Australia, China, and USA). 7,635,996 raw sequencing reads were produced, with 11,794 microsatellites detected and 214,257 primer options designed. 48 microsatellite markers were selected for further validation, with 10 markers amplifying consistently across the four S. oryzae populations. These markers displayed a high level of polymorphism overall (6.67 alleles/locus), though this was slightly lower within populations (3.10–4.88 alleles/locus). We used the markers to conduct a preliminary assessment of genetic structuring among the four S. oryzae populations: three laboratory cultures (New South Wales, Queensland, and Santai) and a field collected population from Kansas. Analyses suggest high levels of genetic differentiation between the sample locations, with a global F_ST of 0.239, and pairwise F_ST values ranging from 0.100 to 0.395. Bayesian clustering analyses suggest these four populations formed four distinct clusters, with a similar pattern identified by Principal Coordinate Analysis. These microsatellite markers, together with our preliminary population genetic analyses, will provide a valuable resource for population genetic research, and contribute to effective integrated pest management strategies in the future.     

Relative quantification of <Emphasis Type="Italic">Vitis vinifera</Emphasis> L. varieties in musts by microsatellite DNA analysis

Varietal wines are defined as made primarily from a single variety of grape, which is identified on the label. However the inclusion of other varieties in their production is permitted under defined percentages. The fact that different grape varieties/varietal wines present far different economical values can attract fraudulent practices. Thus the development of methods, which allow the quantification of those varieties, is of crucial importance. The first approach to the method for the relative quantification of must containing two varieties based on microsatellite DNA analysis is presented. Quantification was achieved by densitometry measurements of the amplification products of the pooled varieties, obtained with loci VVMD6 and VVMD7, after their separation and staining on polyacrilamide gels. We have found that a good correlation between the proportion of each variety in must and the signal intensity of the alleles are dependent on the variety (varietal effect) and the microsatellite locus used. The relative quantification of musts can be accomplished by the presented method depending on the presence of overlapping alleles, and the composition of the varieties and their relative amounts.     

Multifunctional Optical Terminals for Microsatellite Clusters – Design Tradeoffs

We study optical terminals with both communication and ranging capabilities for their potential use in short range free-space applications, typically encountered within a cluster of microsatellites. For our considerations we assume satellites with a unit mass between 10 kg and 100 kg, with mutual distances on the order of a few km, and per link data rates range from a few kbits/s to some 100 Mbit/s. We discuss possible network topologies and multiple access methods, andcompare the performance characteristics of different intensity modulation formats, taking into account not only the task of communication but also that of accurate intra-cluster distance measurement. Our considerations revealbasic tradeoffs to be observed when designing such multifunctional optical terminals.     

不同对虾种间共用微卫星DNA引物的研究

采用已发表的斑节对虾的30对微卫星引物,对部分微卫星引物在中国对虾、凡纳对虾、日本对虾中的通用性进行了研究。通过所建立的降温PCR(Touchdown PCR)方法对3种对虾的DNA进行PCR扩增,筛选出3对引物在3种对虾中均能产生清晰谱带。根据上述结果适当调整PCR反应体系中各试剂的量及反应条件,达到了理想的结果。利用这3对引物对3种对虾进行遗传标记分析,结果显示,PCR扩增产物条带清晰,特异性强,每对引物在3种对虾间扩增出的特异性片段大小几乎一致。研究表明,3种对虾基因组间存在一定程度的相似性,引物W15-16、W21-22和W45-46可直接应用于中国对虾、凡纳对虾、日本对虾、斑节对虾分子标记的基因组比较作图,也为图谱克隆法提供了新的思路。     

微卫星标记技术在大豆遗传作图中的应用

根据文献报道的序列有选择地合成了２０对ＳＳＲ引物,在用以遗传作图的两个亲本中进行了扩增,有１７对引物的扩增产物具有多态性大小范围为７０－３００ｂｐ。其中扩增产和大小差异小于１０－２０ｂｐ的等位基因可通过４％琼脂糖凝胶电脉分开,介绍了多次眯样和多引物ＰＣＲ技术。Ｘ＾２显著性检验证明其符合孟德尔式遗传方式,遗传连锁分析表明其中三个微卫星标记加锁     

Approximation algorithm for coloring of dotted interval graphs

Dotted interval graphs were introduced by Aumann et al. [Y. Aumann, M. Lewenstein, O. Melamud, R. Pinter, Z. Yakhini, Dotted interval graphs and high throughput genotyping, in: ACM-SIAM Symposium on Discrete Algorithms, SODA 2005, pp. 339-348] as a generalization of interval graphs. The problem of coloring these graphs found application in high-throughput genotyping. Jiang [M. Jiang, Approximating minimum coloring and maximum independent set in dotted interval graphs, Information Processing Letters 98 (2006) 29-33] improves the approximation ratio of Aumann et al. [Y. Aumann, M. Lewenstein, O. Melamud, R. Pinter, Z. Yakhini, Dotted interval graphs and high throughput genotyping, in: ACM-SIAM Symposium on Discrete Algorithms, SODA 2005, pp. 339-348]. In this work we improve the approximation ratio of Jiang [M. Jiang, Approximating minimum coloring and maximum independent set in dotted interval graphs, Information Processing Letters 98 (2006) 29-33] and Aumann et al. [Y. Aumann, M. Lewenstein, O. Melamud, R. Pinter, Z. Yakhini, Dotted interval graphs and high throughput genotyping, in: ACM-SIAM Symposium on Discrete Algorithms, SODA 2005, pp. 339-348]. In the exposition we develop a generalization of the problem of finding the maximum number of non-attacking queens on a triangle.     

利用微卫星标记分析核盘菌遗传多样性

利用微卫星（SSR）标记,分析来自欧洲和中国的30个核盘菌菌株的遗传多样性和群体结构。结果表明,3对微卫星引物共扩增出21条清晰的谱带,平均每对引物扩增7条谱带,片段长度为158bp～358bp。根据SSR分析结果,30个核盘菌分离物具有较高的遗传相似性。物种水平的Nei遗传多样性指数为0.139 3,Shannon多样性指数为0.248 8。不同菌株群体的Nei遗传距离都较小,为0.009 6～0.049 6。其中俄罗斯群体和奥地利及英国群体之间的遗传距离最大。从30个菌株的UPGMA聚类分析结果看,核盘菌群体结构与地理来源没有明显的直接关系。许多地理来源相同的菌株分散在不同的组里。仅第三组组内的菌株地理来源一致,均来自于中国,且遗传距离比其他菌株的远。群体遗传分析显示,总群体的基因流比较高（2.111 6）,基因分化系数比较低（0.191 5）。     

Introgression of hatchery rainbow trout in naturalized steelhead populations of western Lake Superior

Fisheries managers and anglers in Minnesota have long been concerned that reproduction in the wild by a hatchery strain of rainbow trout (Oncorhynchus mykiss), called kamloops, could reduce the fitness of naturalized steelhead (migratory rainbow trout) populations in Lake Superior. A previous study found no evidence of kamloops introgression, but a new evaluation is warranted in light of continued stocking and genetic advancements over the past 25 years. We used genotypes from 10 microsatellite DNA loci to assess kamloops ancestry in adult and age-0 rainbow trout samples from 40 streams in Minnesota, one stream in Wisconsin, and two adult broodstocks. We also evaluated genetic population structure for impacts of kamlooops introgression. Overall, the average estimated kamloops ancestry was 8% (range 2–44%) in age-0 juveniles and 4% (1–19%) in adults. The average percentages of kamloops descendants in age-0 and adults were 8% (0–54%) and 5% (0–40%), respectively. Kamloops descendants were found in many Minnesota streams and in Wisconsin’s Bois Brule River, but were most prevalent in streams near the source hatchery, near recent stocking locations, and in lower reaches of longitudinally sampled streams. Feral steelhead broodstock had 9% and 6% kamloops descendants in two years while captive broodstock had no kamloops descendants. Minnesota’s populations showed little spatial genetic structure but were distinct from the Bois Brule population and from kamloops, which indicated that kamloops introgression had not substantially altered structure. Kamloops introgression into Minnesota steelhead populations and impacts on other jurisdictions contributed to the decision to discontinue the kamloops stocking program.