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1.
长期以来,螨类主要依靠其形态特征进行系统学研究。DNA标记是指能反映生物个体或物种间基因组中某种差异特征的DNA片段。近年来,DNA标记技术在螨类系统学研究中得到越来越广泛的应用。本文综述了随机扩增多态性RAPD、限制性内切酶片段长度多态性RFLP、微卫星SSR、核酸序列扩增、扩增片段长度多态性AFLP和直接扩增片段长度多态性DALP等6种DNA标记技术在螨类系统学研究中的应用现状及前景。  相似文献   
2.
Conservation genetics: beyond the maintenance of marker diversity   总被引:8,自引:0,他引:8  
One of the major problems faced by conservation biologists is the allocation of scarce resources to an overwhelmingly large number of species in need of preservation efforts. Both demographic and genetic information have been brought to bear on this problem; however, the role of information obtained from genetic markers has largely been limited to the characterization of gene frequencies and patterns of diversity. While the genetic consequences of rarity may be a contributing factor to endangerment, it is widely recognized that demographic factors often may be more important. Because patterns of genetic marker variation are influenced by the same demographic factors of interest to the conservation biologist, it is possible to extract useful demographic information from genetic marker data. Such an approach may be productive for determining plant mating systems, inbreeding depression, effective population size, and metapopulation structure. In many cases, however, data consisting only of marker frequencies are inadequate for these purposes. Development of genealogical based analytical methods coupled with studies of DNA sequence variation within and among populations is likely to yield the most information on demographic processes from genetic marker data. Indeed, in some cases it may be the only means of obtaining information on the long-term demographic properties that may be most useful for determining the future prospects of a species of interest.  相似文献   
3.
The R1 allele confers on potato a race-specific resistance to Phytophthora infestans. The corresponding genetic locus maps on chromosome V in a region in which several other resistance genes are also located. As part of a strategy for cloning R1, a high-resolution genetic map was constructed for the segment of chromosome V that is bordered by the RFLP loci GP21 and GP179 and includes the R1 locus. Bulked segregant analysis and markers based on amplified fragment length polymorphisms (AFLP markers) were used to select molecular markers closely linked to R1. Twenty-nine of approximately 3200 informative AFLP loci displayed linkage to the R1 locus. Based on the genotypic analysis of 461 gametes, eight loci mapped within the GP21–GP179 interval. Two of those could not be seperated from R1 by recombination. For genotyping large numbers of plants with respect to the flanking markers GP21 and GP179 PCR based assays were also developed which allowed marker-assisted selection of plants with genotypes Rr and rr and of recombinant plants.  相似文献   
4.
A genetic map of potato (Solanum tuberosum L.) integrating molecular markers with morphological and isozyme markers was constructed using a backcross population of 67 diploid potato plants. A general method for map construction is described that differs from previous methods employed in potato and other outbreeding plants. First, separate maps for the female and male parents were constructed. The female map contained 132 markers, whereas the male map contained 138 markers. Second, on the basis of the markers in common the two integrated parental maps were combined into one with the computer programme JoinMap. This combined map consisted of 175 molecular markers, 10 morphological markers and 8 isozyme markers. Ninety-two of the molecular markers were derived from DNA sequences flanking either T-DNA inserts in potato or reintegrated maize transposable elements originating from these T-DNA constructs. Clusters of distorted segregation were found on chromosomes 1,2,8 and 11 for the male parent and chromosome 5 for both parents. The total length of the combined map is 1120 cM.  相似文献   
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Grain-mould is a major problem in grain sorghum utilization as mouldy grain has a reduced quality due to the deterioration of the endosperm and reduced embryo viability. Here, our objective was to use genome mapping to improve knowledge of genetic variation and co-variation for grain-mould incidence and other inter-related agronomic traits. Grain-mould incidence, kernel-milling hardness, grain density, plant height, panicle peduncle length, foliar-disease incidence, and plant color were measured on 125 F5 genotypes derived from a cross of Sureño and RTx430. Quantitative trait loci were detected by means of 130 mapped markers (44 microsatellites, 85 AFLPs, one morphological-trait locus) distributed among ten linkage groups covering 970 cM. One to five QTLs affected each trait, with the exception of grain density for which no QTLs were detected. Grain-mould incidence was affected by five QTLs each accounting for between 10 and 23% of the phenotypic variance. The effects and relative positions of QTLs for grain-mould incidence were in accordance with the QTL distribution of several inter-related agronomic traits (e.g., plant height, peduncle length) and with the correlation between these phenotypic traits and grain-mould incidence. The detection of QTLs for grain-mould incidence was dependent on the environment, which is consistent with heritibility estimates that show strong environmental and genotype × environment effects. Several genomic regions affected multiple traits including one region that affected grain-mould incidence, plant height, panicle peduncle length, and grain-milling hardness, and a second region that influenced grain-mould (in four environments) and plant height. One genomic region, which harbors loci for plant color, influenced the severity of foliar disease symptoms and the incidence of grain-mould in one environment. Collectively QTLs detected in the present population explained between 10% and 55% of the phenotypic variance observed for a given trait.  相似文献   
8.
土壤镉污染对大蒜幼苗生长及根系抗氧化系统的影响   总被引:2,自引:0,他引:2  
赵胡  郑文教  陈杰 《生态学杂志》2008,27(5):771-775
通过土培实验研究了镉污染胁迫对大蒜幼苗生长及根系抗氧化系统的影响.结果表明:与对照组比较,土壤低浓度镉对大蒜幼苗生长略有促进作用,单株鲜质量、干质量、根长及地上部分高度略有增加,而根系活力、可溶性蛋白含量、超氧化物坡化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性显著升高,抗氧化防御酶系统仍保持平衡,表现在膜脂质过氧化产物(MDA)含量与对照组无明显差异;但随着土壤镉浓度的进一步增加,大蒜平均单株鲜质量、干质量、平均最大根长及地上部分高度均显著降低,同时,根系活力和可溶性蛋白含量增幅逐渐减弱,抗氧化防御酶系统平衡受到破坏,根系MDA含量显著上升.大蒜对镉吸收积累主要在根部,而向地上部分转运较少.  相似文献   
9.
Utilizing intersimple sequence repeat (ISSR) markers, 18 mulberry (Morus spp.) germplasm collections were studied for genetic variability, phylogenetic relationship, and association with protein and sugar content. The genetic polymorphism exhibited by ISSR primers was 100%, and the genetic diversity recorded among the mulberry accessions had an average of 0.263 ± 0.094. Dendrogram (unweighted pair group method analysis) clustered the mulberry accessions into two major groups, one comprised the accessions collected from north or northeast regions of India, and the other comprised three subclusters and one isolate, i.e., Assamjati, a collection from Assam. Another subcluster contained accessions collected from Kerala, which belong to Morus indica. These accessions of M. indica from Kerala were found to be genetically diverse from north and northeast India. Multidimensional scaling of the ISSR data clearly separated the mulberry accessions according to their genetic diversity and protein content. Mulberry accessions were arbitrarily grouped into three classes viz. very low, moderate, and high in terms of protein and sugar content using standard statistical programs. Stepwise multiple regression analysis identified four ISSR markers (8351,600, 8355,600, 8222,500, and 8072,500) associated with protein content with highly positive correlation (p < 0.001) with linear curves with high F values (18.055 to 48.674; p < 0.001). In case of sugar content, four ISSR markers viz. 812900, 8171,500, 8261,500, and 8108,000 showed negative correlation. Hence, DNA markers for proteins seem promising and may be used in marker-assisted breeding program.  相似文献   
10.
Group-wise diversity of sediment methylotrophs of Chilika lake (Lat. 19°28′–19°54′N; Long. 85°06′–85°35′E) Odisha, India at various identified sites was studied. Both the culturable and unculturable (metagenome) methylotrophs were investigated in the lake sediments employing both mxaF and 16S rRNA genes as markers. ARDRA profiling, 16S rRNA gene sequencing, PAGE profiling of HaeIII, EcoRI restricted mxaF gene and the mxaF gene sequences using culture-dependent approach revealed the relatedness of α-proteobacteria and Methylobacterium, Hyphomicrobium and Ancyclobacter sp. The total viable counts of the culturable aerobic methylotrophs were relatively higher in sediments near the sea mouth (S3; Panaspada), also demonstrated relatively high salinity (0.1 M NaCl) tolerance. Metagenomic DNA from the sediments, amplified using GC clamp mxaF primers and resolved through DGGE, revealed the diversity within the unculturable methylotrophic bacterium Methylobacterium organophilum, Ancyclobacter aquaticus, Burkholderiales and Hyphomicrobium sp. Culture-independent analyses revealed that up to 90 % of the methylotrophs were unculturable. The study enhances the general understandings of the metagenomic methylotrophs from such a special ecological niche.

Electronic supplementary material

The online version of this article (doi:10.1007/s12088-015-0510-3) contains supplementary material, which is available to authorized users.  相似文献   
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