利用分子标记分析高粱的遗传多样性及其在种质创新中的应用

分子标记由于能够反映DNA水平上的遗传变异而成为研究遗传多样性的重要方法。本文综述了利用分子标记分析高粱遗传多样性的研究进展,并阐述了遗传多样性分析在种质创新中的应用方向,提出了利用分子标记分析高粱遗传多样性研究中尚需进一步加强的研究内容。     

共显性分子标记基因型数据转换为二元型数据的处理软件及其在研究种质资源遗传多样性中的意义

遗传多样性研究是植物种质资源有效利用和保护的重要基础.遗传多样性研究所采用的分子标记工具主要有显性和共显性两种,两种不同类型的分子标记将产生不同的数据类型.显性分子标记产生二元型数据,共显性分子标记产生基因型数据.数据形式不同给遗传多样性的分析和研究带来多方面的困难,不同类型数据之间的互相比较也需要将基因型数据进行二元型转换.本研究基于Excel平台,设计开发了将基因型数据转换成二元型数据的处理软件.该软件按照基因型数据向二元型数据转换的原理,可以将庞大的分子标记基因型数据矩阵,迅速、高效、准确地转换成二元型(0、1)数据矩阵.利用显性分子标记ISSR和共显性分子标记SSR对野生大豆居群遗传多样性的案例分析表明,将共显性分子标记的基因型数据转换为二元型数据,有利于种质资源遗传多样性研究中不同分子标记获取的遗传多样性结果之间的比较和综合分析.     

鸡的遗传多样性的研究方法及研究进展

遗传多样性是生物学研究中的一个重要领域,研究鸡的遗传多样性,不仅能加强生物多样性的保护。同时对起源进化、分类鉴定及遗传育种等都有重要的意义。本文对目前DNA水平鸡的遗传多样性的研究方法和研究进展进行了详细的阐述。重点介绍了DNA分子标记的特征;概括了在鸡遗传多样性分子标记的方法,包括微卫星分子标记(SSR)、扩增片段长度多态性(AFLP)、随机扩增多态性标记(RAPD)、限制性片段长度多态性标记(RFLP)和单核苷酸多态性标记(SNP)。本文综述了最近有关鸡DNA水平的遗传多样性的研究方法在系统学、遗传结构、生物地理等研究中的应用情况;提出在研究鸡遗传多样性时,可根据研究的目的,选择合适的方法。     

中国猕猴遗传多样性研究进展

从形态学、染色体、蛋白质、DNA水平等方面对中国猕猴的遗传多样性进行了综述,以期为我国猕猴资源的保护和利用提供理论基础,为猕猴遗传多样性的研究提供参考.染色体核型和蛋白质分析表明中国猕猴遗传多样性有限,DNA多态性分析表明中国猕猴具有丰富的遗传多样性.基于线粒体控制区部分序列的分析有助于中国猕猴系统发育与进化的研究,Neighbor-joining进化树和Median-Joining网络图将中国猕猴分为7个类群.     

吉林省野生杏种质资源遗传多样性研究

遗传多样是生物多样性的核心,决定着生物多样性的其他方面,是在分子层面上揭示生物多样性的本质.近10年来世界上遗传多样性研究方法发展迅速,主要手段是运用基于DNA分子标记方法.采用DNA-RAPD分子标记方法,对吉林省野生杏资源进行了遗传多样性研究.旨在进一步从分子水平上对吉林省野生杏资源的生物多样性进行研究,目的是从理论上证明其资源多样性非常丰富.     

遗传标记及其在林木研究中的应用

遗传标记经历了形态标记、细胞学标记、生化标记和分子标记等4个阶段,其中分子标记的发展最为迅猛和有效。本文比较了几种主要分子标记方法的特点,为更好地利用分子标记提供了理论依据,并对分子标记在林木遗传多样性研究、遗传育种、DNA指纹图谱的构建、亲缘关系鉴定及分类研究等方面的应用做了介绍。     

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。     

分子标记在食（药）用真菌遗传多样性研究中的应用

食（药）用真菌在经济和生态方面都具有重要意义,其遗传多样性研究是资源可持续利用和生物保护学研究的基础,有利于食（药）用真菌种质资源的收集、保存、评价和利用,也有助于其分类学、系统学及进化等的研究。遗传多样性的研究方法很多,分子标记是目前最常用最有效的方法之一。综合分析了分子标记在食（药）用真菌遗传多样性研究中的应用,比较了各种标记的应用范围、优缺点,探讨了分子标记用于食（药）用真菌遗传多样性评价的前景及问题。     

分子标记在啤酒花种质资源研究中的应用

该论文利用分子生物学中常用的DNA分子标记对世界各地现存的野生和栽培的啤酒花种质资源遗传多样性研究的应用进展做一综述。通过查阅和研读20世纪90年代以来发表的各类文献进行归纳总结。发现DNA分子标记相比形态学标记和细胞学标记具有结果准确、稳定的特点,常用的分子标记技术有RAPD、RFLP、ISSR、SSR、AFLP、EST等;研究发现北美洲的啤酒花遗传多样性要高于欧洲的啤酒花,基因变异程度也相对较高;野生啤酒花的基因序列具有丰富的基因多样性,可在分子杂交遗传育种中作为一个种质去改善栽培品种的某些不良性状。因此,利用分子标记研究啤酒花的遗传多样性将对啤酒花的优良育种提供理论指导和技术支持,目前较为理想的技术是SSR和AFLP。     

微卫星DNA标记及其在鱼类遗传多样性研究中的应用

微卫星DNA作为第二代分子遗传标记是高等真核生物基因组中种类多、分布广、具有高度的多态性和杂合度的分子标记,由于其具有多态性检出率高、信息含量大、共显性标记、实验操作简单、结果稳定可靠等优点,已经成为种群遗传学研究中被广泛应用的分子遗传标记。微卫星DNA标记技术在鱼类的群体遗传结构的分析、物种遗传多样性的鉴定以及遗传基因连锁图谱的构建等方面已初步得到应用。该文就微卫星技术的原理方法,在鱼类遗传多样性研究中的应用概况以及应用范围和注意事项等方面进行综述。为微卫星技术在鱼类遗传多样性研究中应用提供了理论参考。     

云南地区恒河猴线粒体DNA控制区遗传多态性研究

目的从分子水平探讨云南地区恒河猴遗传多样性,为今后开展恒河猴遗传资源的保护及合理利用提供借鉴和背景资料。方法采用PCR直接测序法测定云南地区恒河猴96份样品的线粒体DNA控制区全序列,用Mege 4.0和DNA SP软件对变异位点数、简约信息位点数、单倍型、单倍型多样度、核苷酸多样度等遗传信息进行分析,基于邻接法（neighbor-joining,NJ）和最小进化法（minimum-evolution,ME）构建系统发生树。结果在96份样品中,共检测出了149个多态性位点,定义了46种单倍型,单倍型多样度（Hd）为0.968±0.007,核苷酸多样度（Pi）为0.020。结论云南地区恒河猴存在着较丰富的遗传多态性。     

恒河猴群微卫星DNA多态性的分析

目的　确立一种对恒河猴群个体的遗传物质进行准确可靠、快速简便的遗传检测方法。方法　利用聚合酶链反应 (PCR)扩增技术对 2 0只恒河猴群个体间进行了DNA多态性的分析。结果　筛选出 9个微卫星DNA位点具有显著多态性 ,4个微卫星DNA位点没有多态性 ,还有 2个位点等位基因数目较少。结论　利用这些多态性微卫星位点建立一种对恒河猴群个体进行有效、准备可靠、快捷简便的遗传背景监测方法。     

湖北钟祥一上新世猕猴牙齿

在湖北钟祥县发现一颗猕猴的上臼齿,它出自青白色泥质粘土层。时代为上新世。这颗牙齿构造较复杂,但已显示了现生猕猴牙齿的基本结构,因而订为一新种 Macaca youngi(sp.nov.)在我国所发现的第三纪猕猴化石较少,这颗牙齿的发现为研究猕猴的演化增添了一点资料。     

Genetic diversity in European pigs utilizing amplified fragment length polymorphism markers

The use of DNA markers to evaluate genetic diversity is an important component of the management of animal genetic resources. The Food and Agriculture Organisation of the United Nations (FAO) has published a list of recommended microsatellite markers for such studies; however, other markers are potential alternatives. This paper describes results obtained with a set of amplified fragment length polymorphism (AFLP) markers as part of a genetic diversity study of European pig breeds that also utilized microsatellite markers. Data from 148 AFLP markers genotyped across samples from 58 European and one Chinese breed were analysed. The results were compared with previous analyses of data from 50 microsatellite markers genotyped on the same animals. The AFLP markers had an average within-breed heterozygosity of 0.124 but there was wide variation, with individual markers being monomorphic in 3-98% of the populations. The biallelic and dominant nature of AFLP markers creates a challenge for their use in genetic diversity studies as each individual marker contains limited information and AFLPs only provide indirect estimates of the allelic frequencies that are needed to estimate genetic distances. Nonetheless, AFLP marker-based characterization of genetic distances was consistent with expectations based on breed and regional distributions and produced a similar pattern to that obtained with microsatellites. Thus, data from AFLP markers can be combined with microsatellite data for measuring genetic diversity.     

Multiplexed microsatellites for rapid identification and characterization of individuals and populations of Cercopithecidae

Cross-amplification of 15 human microsatellites was performed successfully in cynomolgus (Macaca fascicularis) and rhesus (M. mulatta) macaques and 11 other Cercopithecidae species of biomedical and conservation relevance. To allow for quick, efficient, and high-throughput genotyping to assess intra- and interspecific genetic variation, we performed three multiplex sets, each comprised of five markers from different parts of the genome (i.e., autosomes, the MHC region, and the X-chromosome). These multiplex sets are likely to reveal allelic divergence between taxa, which could be used for their discrimination. Population studies on three regional populations of M. fascicularis and one of M. mulatta revealed that most of the loci, with the exception of one monomorphic locus, displayed polymorphisms (the expected heterozygosities were 0.48-0.91 for M. fascicularis, and 0.61-0.93 for M. mulatta), which makes them useful for population genetics. For the multiplex set M1, including the nonlinked autosomal markers, low probabilities of identity were observed: P(ID) values ranged from 8 x 10(-7) to 3 x 10(-5). This multiplex set is reliable for forensic applications, such as individual identification, parentage testing, and kinship analysis, in wild and captive populations.     

The effects of encoding data in diversity studies and the applicability of the weighting index approach for data analysis from different molecular markers

The use of molecular markers to study genetic diversity represents a breakthrough in this area, because of the increase in polymorphism levels and phenotypic neutrality. Codominant markers, such as microsatellites (SSR), are sensitive enough to distinguish the heterozygotes in genetic studies. Despite this advantage, there are some studies that ignore this feature and work with encoded data because of the simplicity of the evaluation, existence of polyploids and need for the combined analysis of different types of molecular markers. Thus, our study aims to investigate the consequences of these encodings on simulated and real data. In addition, we suggest an alternative analysis for genetic evaluations using different molecular markers. For the simulated data, we proposed the following two scenarios: the first uses SNP markers, and the second SSR markers. For real data, we used the SSR genotyping data from Coffea canephora accessions maintained in the Embrapa Germplasm Collection. The genetic diversity was studied using cluster analysis, the dissimilarity index, and the Bayesian approach implemented in the STRUCTURE software. For the simulated data, we observed a loss of genetic information to the encoded data in both scenarios. The same result was observed in the coffee studies. This loss of information was discussed in the context of a plant-breeding program, and the consequences were weighted to germplasm evaluations and the selection of parents for hybridization. In the studies that involved different types of markers, an alternative to the combined analysis is discussed, where the informativeness, coverage and quality of markers are weighted in the genetic diversity studies.     

Biodiversity assessment using markers for ecologically important traits

Most studies of genetic variation within species to date are based on random markers. However, how well this correlates with quantitative variation is contentious. Yet, functional, or'ecotypic' variation in quantitative traits determines the ecological niche of a species, its future evolutionary potential, and, for livestock, crops and their wild relatives, their usefulness as a genetic resource for breeding. But nowadays we can also assess genetic diversity using markers directly targeted at specific genes or gene families. Such gene-targeted, multilocus profiles of markers can contribute to ex-situ management of genetic resources, ecological studies of diversity, and conservation of endangered species.     

An initial genetic linkage map of the rhesus macaque (Macaca mulatta) genome using human microsatellite loci

Rhesus macaques (Macaca mulatta) are the most widely used nonhuman primate species in biomedical research. To create new opportunities for genetic and genomic studies using rhesus monkeys, we constructed a genetic linkage map of the rhesus genome. This map consists of 241 microsatellite loci, all previously mapped in the human genome. These polymorphisms were genotyped in five pedigrees of rhesus monkeys totaling 865 animals. The resulting linkage map covers 2048 cM including all 20 rhesus autosomes, with average spacing between markers of 9.3 cM. Average heterozygosity among those markers is 0.73. This linkage map provides new comparative information concerning locus order and interlocus distances in humans and rhesus monkeys. The map will facilitate whole-genome linkage screens to locate quantitative trait loci (QTLs) that influence individual variation in phenotypic traits related to basic primate anatomy, physiology, and behavior, as well as QTLs relevant to risk factors for human disease.     

Isolation of novel microsatellites using FIASCO by dual probe enrichment from Jatropha curcas L. and study on genetic equilibrium and diversity of Indian population revealed by isolated microsatellites

Jatropha curcas L. belongs to family Euphorbiaceae, native to South America attained significant importance for its seed oil which can be converted to biodiesel, a renewable energy source alternative to conventional petrodiesel. Very few attempts were made to isolate novel microsatellite markers and assessment of the extent of genetic equilibrium and diversity that exists in J. curcas. Therefore, the present investigation was undertaken to isolate the novel microsatellites and access genetic equilibrium, diversity that exists among 44 diverse germplasm collected from distinct geographical areas in India using isolated microsatellites. The overall efficiency of the enrichment of microsatellite by dual probe in the present study found to be 54% and among the sequences obtained the percentage of sequences having suitable flanking regions for the primer designing was found to be 89.58%. The mean co-efficient of genetic similarity (CGS) was found to be 0.97. The overall diversity obtained by microsatellites was found to be low in comparison with the diversity reported by multilocus markers systems observed in earlier studies; however, the good allele polymorphism was observed. The overall dendrogram of microsatellite analysis resulted in random clustering of germplasm and not in accordance to geographical area of collection. The present study, diversity analysis using microsatellite markers concludes the low genetic diversity and genetic disequlibrium of J. curcas in India and will provide pavement for further intra-population studies on narrow geographical areas to understand the population genetic structure, phylogeography and molecular ecological studies. The germplasm characterized, and the microsatellite markers isolated and characterized in the present study can be employed efficiently in breeding programs for genetic improvement of the species through marker assisted selection and QTL analysis, for further genetic resource management and help in making the J. curcas as potential crop with superior agronomical traits.