AFLP标记在研究家蚕遗传多态性方面的应用

AFLP是一种多态检出效率很高的分子标记技术,在构建遗传图谱,遗传多态性研究,重建分子系统演化树,品种鉴定,基因克隆等众多研究领域有着其它分子标记技术不可比拟的优势。本文在前人用AFLP技术对植物多态性研究的基础上,将AFLP用于家蚕的遗传多态性研究,结果发现在家蚕中同样具有丰富的AFLP标记的多态性。由此暗示AFLP技术亦适合研究家蚕等昆虫类动物的遗传多态性,构建遗传图谱,或用于其分子生态学,分子进化和分类等方面的研究。此外本文还探讨了适合于家蚕等昆虫的AFLP分析的实验条件。     

分子标记及其在植物遗传育种中的应用

遗传标记可以说是生物群体中可识别的遗传多态性的一种表现形式。随着遗传研究特别是遗传作图的不断深入,遗传标记已从传统的以等位基因的表型识别为基础的形态标记、以染色体的结构和数目为特征的细胞学标记,及具有组织、发育及物种特异性的同工酶标记,拓展到目前已广泛应用的以ＤＮＡ多态性为基础的分子标记技术。现代分子标记技术的出现和发展为植物遗传育种研究的许多领域注入了新的活力。本文着重就目前植物遗传育种中所应用的一些主要分子标记技术及其应用作一概述。１　常用的分子标记技术自８０年代初有人提出用ＲＦＬＰ作为遗传…     

微卫星DNA标记技术及其在昆虫学上的应用

微卫星DNA标记作为一种多态性和稳定性高、重复性好、呈共显性的分子遗传标记技术,目前已被广泛应用于昆虫学的研究中。本文介绍了微卫星DNA标记的基本原理和特点,并综述了近年来该技术在昆虫种群遗传结构及分化、生物学特性与习性、遗传图谱的构建、基因定位以及系统发生等领域中的应用。     

DNA分子标记技术及其在植物遗传多样性研究中的应用

本文阐述了ＤＮＡ限制性片段长度多态性、ＤＮＡ指纹图谱、单位点小卫星、单位点微卫星及随机扩增多态ＤＮＡ等主要的ＤＮＡ遗传标记技术的基本原理和方法．综述了不同ＤＮＡ标记的优缺点及其在植物遗传多样性研究中的应用前景．     

SSR分子标记在作物遗传育种中的应用

SSR(simple sequence repeat)是建立在PCR技术上的一种广泛应用的分子标记,具有含量丰富、多态性高、共显性等优点。本文简要介绍了SSR分子标记技术的原理和特点,重点介绍了SSR分子标记技术在作物遗传育种中的应用,主要在作物遗传多样性、基因定位、分子辅助标记、遗传图谱构建、品种鉴定和纯度鉴定等方面进行阐述。     

几种分子标记技术的比较及其在中药材鉴定中的应用

分子标记技术是指能够反映生物个体或种群之间基因组中某种差异的特异性片段,是DNA水平上遗传多态性的反映,大多数DNA分子标记是以电泳谱带的形式表现个体之间的DNA差异。对几种分子标记技术进行了比较,并就其在中药材鉴定方面的应用以及意义做以综述。     

DNA分子标记技术在植物种质资源鉴定中的应用

DNA分子标记技术从基因水平进行标记,不受环境因素、个体发育阶段及组织部位影响,多态性强,已成为生物学主要遗传标记手段之一。综述了几种主要DNA分子标记技术的原理和优缺点,着重阐述了其在植物种质资源鉴定方面的应用。     

DNA分子标记在实验动物遗传分析中的应用

DNA分子标记技术很多,基本都是建立在RFLP、PCR和重复顺序的基础上的。本文重点介绍了限制性片段长度多态性（RFLP）标记、随机扩增多态性DNA（RAPD）标记、微卫星DNA（STR）标记、DNA指纹（DFP）标记、扩增片段长度多态性（AFLP）标记等几种重要的DNA分子标记技术的定义、结构、分布、组成、保守性、优点及丰富的多态性等。并重点介绍了微卫星DNA（STR）标记在分子遗传监测、遗传多样性分析和遗传血缘关系及个体识别等领域的应用。     

DNA分子标记技术及其在水产动物遗传上的应用研究

随着DNA分子标记技术的发展,其在动物遗传上发挥了重大作用,使用DNA分子标记可以观察到整个基因组的遗传多样性。目前,在水产养殖种类中使用的遗传标记主要包括线粒体DNA、RFLP、RAPD、AFLP、微卫星、SNP和EST标记。DNA分子标记的应用使得人们对水产养殖动物的遗传多样性、近亲繁殖、种类和品系鉴定以及遗传连锁图谱建立的研究都取得了很大进展,也加快了数量性状位点(QTL)基因的鉴定作为分子标记辅助选择(MAS)的研究。将这些标记技术在水产动物上的应用进行了论述,以及如何从人类基因组工程和斑马鱼这种模式鱼的研究中得到启发,更好的应用于水产动物基因组学和遗传学研究做一讨论。     

AFLP分子标记技术在昆虫学研究中的应用

AFLP分子标记技术是一种建立在PCR技术和RFLP标记基础上的新的DNA指纹分析技术 ,具有多态性丰富、结果稳定可靠、重复性好、所需DNA量少、可以在不知道基因组序列的情况下进行研究等特点 ,现已广泛用于构建遗传图谱、遗传多样性研究、系统进化及分类学、遗传育种和品质鉴定以及基因定位等方面。该文介绍了AFLP标记技术的原理以及在昆虫学研究中的应用。     

Molecular marker systems in insects: current trends and future avenues

Insects comprise the largest species composition in the entire animal kingdom and possess a vast undiscovered genetic diversity and gene pool that can be better explored using molecular marker techniques. Current trends of application of DNA marker techniques in diverse domains of insect ecological studies show that mitochondrial DNA (mtDNA), microsatellites, random amplified polymorphic DNA (RAPD), expressed sequence tags (EST) and amplified fragment length polymorphism (AFLP) markers have contributed significantly for progresses towards understanding genetic basis of insect diversity and for mapping medically and agriculturally important genes and quantitative trait loci in insect pests. Apart from these popular marker systems, other novel approaches including transposon display, sequence-specific amplification polymorphism (S-SAP), repeat-associated polymerase chain reaction (PCR) markers have been identified as alternate marker systems in insect studies. Besides, whole genome microarray and single nucleotide polymorphism (SNP) assays are becoming more popular to screen genome-wide polymorphisms in fast and cost effective manner. However, use of such methodologies has not gained widespread popularity in entomological studies. The current study highlights the recent trends of applications of molecular markers in insect studies and explores the technological advancements in molecular marker tools and modern high throughput genotyping methodologies that may be applied in entomological researches for better understanding of insect ecology at molecular level.     

Advances in molecular marker techniques and their applications in plant sciences

Detection and analysis of genetic variation can help us to understand the molecular basis of various biological phenomena in plants. Since the entire plant kingdom cannot be covered under sequencing projects, molecular markers and their correlation to phenotypes provide us with requisite landmarks for elucidation of genetic variation. Genetic or DNA based marker techniques such as RFLP (restriction fragment length polymorphism), RAPD (random amplified polymorphic DNA), SSR (simple sequence repeats) and AFLP (amplified fragment length polymorphism) are routinely being used in ecological, evolutionary, taxonomical, phylogenic and genetic studies of plant sciences. These techniques are well established and their advantages as well as limitations have been realized. In recent years, a new class of advanced techniques has emerged, primarily derived from combination of earlier basic techniques. Advanced marker techniques tend to amalgamate advantageous features of several basic techniques. The newer methods also incorporate modifications in the methodology of basic techniques to increase the sensitivity and resolution to detect genetic discontinuity and distinctiveness. The advanced marker techniques also utilize newer class of DNA elements such as retrotransposons, mitochondrial and chloroplast based microsatellites, thereby revealing genetic variation through increased genome coverage. Techniques such as RAPD and AFLP are also being applied to cDNA-based templates to study patterns of gene expression and uncover the genetic basis of biological responses. The review details account of techniques used in identification of markers and their applicability in plant sciences.     

Male‐specific alleles in the Ryukyu drywood termite Neotermes sugioi

Sex‐determination systems often show remarkable diversity in upstream signals, although downstream genes are broadly conserved. Therefore, the downstream genes have been investigated in various taxa, but the most upstream signals determining sex in insects have been well‐described mainly in model organisms, including fruit flies and honey bees, and not in hemimetabolous insects such as termites. Identification of sex‐linked genetic markers in termites is important to the survey of primary sex‐determination signals. Here, we report male‐specific alleles at the microsatellite locus NK12‐1 in the Ryukyu drywood termite Neotermes sugioi (Kalotermitidae). This study provides the third example of a genetic marker linked with sexual phenotype in termites, which is a small but important step to elucidate the evolutionary process of the sex‐determination system in termites.     

Current status and future possibilities of molecular genetics techniques in <Emphasis Type="Italic">Brassica napus</Emphasis>

As PCR methods have improved over the last 15 years, there has been an upsurge in the number of new DNA marker tools, which has allowed the generation of high-density molecular maps for all the key Brassica crop types. Biotechnology and molecular plant breeding have emerged as a significant tool for molecular understanding that led to a significant crop improvement in the Brassica napus species. Brassica napus possess a very complicated polyploidy-based genomics. The quantitative trait locus (QTL) is not sufficient to develop effective markers for trait introgression. In the coming years, the molecular marker techniques will be more effective to determine the whole genome impairing desired traits. Available genetic markers using the single-nucleotide sequence (SNP) technique and high-throughput sequencing are effective in determining the maps and genome polymorphisms amongst candidate genes and allele interactions. High-throughput sequencing and gene mapping techniques are involved in discovering new alleles and gene pairs, serving as a bridge between the gene map and genome evaluation. The decreasing cost for DNA sequencing will help in discovering full genome sequences with less resources and time. This review describes (1) the current use of integrated approaches, such as molecular marker technologies, to determine genome arrangements and interspecific outcomes combined with cost-effective genomes to increase the efficiency in prognostic breeding efforts. (2) It also focused on functional genomics, proteomics and field-based breeding practices to achieve insight into the genetics underlying both simple and complex traits in canola.     

几种基于PCR的分子标记在甘薯遗传多样性研究中的应用

遗传多样性是甘薯品种遗传改良的基础。由于分子标记具有数量极大、不受环境及基因表达与否的限制、多为共显性、不影响生物性状表现等优点,现已在甘薯遗传多样性研究中得到广泛应用。本文比较了RAPD、AFLP、SSR、ISSR和SRAP等几种基于PCR的分子标记方法,分别从遗传差异和亲缘聚类分析两方面,对它们在甘薯遗传多样性研究中的应用进行了综述。对比分析表明ISSR是一种共显性、成本较低、重复性好、多态性较高且非常有发展前途的分子标记,并已经被广泛应用到甘薯遗传多样性、物种亲缘关系、系统分类和辅助育种研究中。     

Insights into genome differentiation: pheromone-binding protein variation and population history in the European corn borer (Ostrinia nubilalis)

Examination of sequence variation at nuclear loci can give insights into population history and gene flow that cannot be derived from other commonly used molecular markers, such as allozymes. Here, we report on sequence variation at a single nuclear locus, the pheromone-binding protein (PBP) locus, in the European corn borer (Ostrinia nubilalis). The European corn borer has been divided into three races in New York State on the basis of differences in pheromone communication and life history. Previous allozyme data have suggested that there is a small but significant amount of genetic differentiation between these races. The PBP does not appear to be involved in the pheromone differences between these races. Examination of variation at the PBP locus in the three races reveals no fixed differences between races despite high levels of polymorphism. There also appears to have been considerable recombination in the history of the pheromone-binding protein alleles. Observation of both recombination between alleles and lack of significant nucleotide or insertion/deletion divergence between races leads us to suggest that these populations are either recently diverged or have continued to exchange genetic material subsequent to divergence in pheromone communication and life history.     

A robust method for detecting single‐nucleotide changes as polymorphic markers by PCR

Numerous techniques in plant molecular genetic analysis, such as mapping and positional cloning techniques, rely on the availability of molecular markers that can differentiate between alleles at a particular locus. PCR-based cleaved amplified polymorphic sequences (CAPS) markers have been widely used as a means of rapidly and reliably detecting a single-base change that creates a unique restriction site in one of a pair of alleles. However, the majority of single-nucleotide changes do not create such sites and thus cannot be used to create CAPS markers. In this paper, a modification of the CAPS technique that allows detection of most single-nucleotide changes by utilizing mismatched PCR primers is described. The mismatches in the PCR primers, in combination with the single-nucleotide change, create a unique restriction site in one of the alleles.     

Molecules and migration: biogeographical studies in cruciferous plants

In the past two decades our understanding of plant biogeography has been improved substantially by the introduction of various molecular marker systems. Especially within the angiosperms, maternally inherited chloroplast DNA based data sets have elucidated not only genetic relatedness but also geographic structuring of genetic variation. These findings were based on the observation that DNA molecules might mutate during migration, which consequently found its manifestation in the term phylogeography introduced in the late 80s by John Avise. However, other markers such as codominantly inherited allozymes were used before the advent of DNA techniques and were used in theoretical population genetic studies. In actual phylogeographic studies, highly variable markers, such as AFLPs (amplified fragment length polymorphisms), were needed to unravel recent species histories (e.g. pleistocenic differentiation). The levels of molecular variation at such markers are closer to that of allelic variation measured with allozymes. Hence, an increasing number of studies have relied on highly polypmorphic markers, such as DNA microsatellite loci. Herein, we try to present an overview on the various biogeographic and phylogeographic studies using various molecular (including isozyme) markers and methodological approaches to analyse them, concentrating on studies done with representatives of the Brassicaceae family.     

Genetic variation of chloroplast and nuclear markers in natural populations of hazelnut (Corylus avellana L.) in Germany

Corylus avellana L. (hazel) is a long-lived, monoecious and wind-pollinated shrub species, widespread all over Europe. In Germany, hazel is intensively traded and planted, and thus is of central interest from a nature conservancy point of view. To assess the within- and between-population differentiation of hazel, 20 natural populations (18 from Germany, one from Italy and one from Hungary) were investigated genetically. Seven isozyme systems comprising 11 gene loci were analysed in up to 100 samples (average 92.6) per population, amplified fragment length polymorphisms (AFLP) were analysed in up to 50 samples (average 47.4) and nine cpDNA-SSR markers were assessed in 20 samples per population. Results for overall isozyme variability with Na 2.46 alleles per locus, allelic diversity (Ne) 1.39, expected heterozygosity He 21 % and 79 % polymorphic loci were in accordance with the findings of previous studies. The respective values for AFLPs were lower, but both marker systems revealed the same level of about 3.5 % differentiation between populations. For cpSSR only the Italian sample showed within-population variation and the two haplotypes were completely differentiated from all other populations expressing a unique genetic structure with one single haplotype. Among the three marker systems AFLPs showed the best ability to differentiate between populations. While only one isozyme locus revealed significant differentiation, 41 AFLP loci showed highly significant differentiation between all populations, but 26 loci when only German populations were considered. Consequently geographic differentiation analyses focused mainly on molecular markers. Mantel tests showed significant correlations between genetic and geographic distance, but in the unweighted pair-group method with arithmetic mean analyses, adjacent populations did not always form clusters. While chloroplast markers were able to clearly distinguish only the Hungarian population, the nuclear markers revealed clear spatial genetic structures. The correlations between geographic and genetic distance was high for AFLPs. The correlograms illustrate this effect for all populations as well as for the German populations.     

DNA markers linked to Malus floribunda 821 scab resistance

Breeding resistant apple plants is an alternative way to control fungal pathogens reducing the environmental impact due to the use of pesticides. The breeding of apple cultivars resistant to Venturia inaequalis could be much improved by marker-assisted selection. A molecular marker closely linked to the resistance locus called Vf could replace selection based on infection studies. To find such molecular markers, DNA of progenies from crossings of a resistant and a susceptible apple tree was subject to bulked segregant analysis. Two markers were found with a genetic distance of 10.6% and 19.7% recombination frequency to the Vf locus.