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1.
畜禽遗传资源的保存对应对未来的育种需要和畜牧业的可持续利用是非常重要的。分子标记广泛应用于大多数畜禽品种及分子变异分析技术的发展,促进了分析品种遗传变异的能力。作者对用于度量畜禽遗传资源的群内遗传多样性评价方法及其在确定种内遗传多样性,以及保种方案中的应用进行了综述。 相似文献
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遗传多样性的研究主要包括形态学水平,染色体水平、蛋白质水平、DNA水平等。中国地方鸡种类繁多,研究地方鸡种的遗传多样性,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意义。20世纪80年代以来,分子生物学技术的快速发展为遗传多样性检测提供了更直接、更精确的方法,即直接通过分析DNA水平的序列变化检测动物遗传多样性。DNA分析方法成为目前最有效的遗传分析方法,避免了根据表型性推断基因型时可能产生的误差。作者对目前中国各种鸡群的遗传多样性在DNA水平的研究进行了综述,旨在发掘地方鸡种的优良基因,为地方鸡种的分子育种、改良提供参考。 相似文献
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H Woelders J Windig SJ Hiemstra 《Reproduction in domestic animals = Zuchthygiene》2012,47(Z4):264-273
Many local breeds are currently at risk because of replacement by a limited number of specialized commercial breeds. Concurrently, for many breeds, allelic diversity within breeds declines because of inbreeding. Gene banking of germplasm may serve to secure the breeds and the alleles for any future use, for instance to recover a lost breed, to address new breeding goals, to support breeding schemes in small populations to minimize inbreeding, and for conservation genetics and genomics research. Developments in cryobiology and reproductive technology have generated several possibilities for preserving germplasm in farm animals. Furthermore, in some mammalian and bird species, gene banking of material is difficult or impossible, requiring development of new alternative methods or improvement of existing methods. Depending on the species, there are interesting possibilities or research developments in the use of epididymal spermatozoa, oocytes and embryos, ovarian and testicular tissue, primordial germ cells, and somatic cells for the conservation of genetic diversity in farm- and other animal species. Rapid developments in genomics research also provide new opportunities to optimize conservation and sampling strategies and to characterize genome-wide genetic variation. With regard to gene banks for farm animals, collaboration between European countries is being developed through a number of organizations, aimed at sharing knowledge and expertise between national programmes. It would be useful to explore further collaboration between countries, within the framework of a European gene banking strategy that should minimize costs of conservation and maximize opportunities for exploitation and sustainable use of genetic diversity. 相似文献
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Analysis of genetic diversity and the determination of relationships among western Mediterranean horse breeds using microsatellite markers 总被引：2，自引：0，他引：2
D. Marletta I. Tupac-Yupanqui S. Bordonaro D. García A. M. Guastella A. Criscione J. Cañón & S. Dunner 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2006,123(5):315-325
The distribution of genetic diversity and the genetic relationships among western Mediterranean horse breeds were investigated using microsatellite markers. The examined sample included seven Spanish and three Italian local horse breeds and populations, plus a Spanish Thoroughbred outgroup. The total number of animals examined was 682 (on average 62 animals per breed; range 20–122). The microsatellite marker set analysed provided 128 alleles (10.7 alleles per locus). Within‐breed genetic diversity was always high (>0.70), with breeds contributing about 8% of the total genetic variability. The mean molecular coancestry of the entire population examined was 0.205, Losino being the breed that contributed most. In addition to Nei's standard and Reynolds’ genetic distances, pair‐wise kinship distance and molecular coancestry were estimated. Remarkably similar breed rankings were obtained with all methods. Clustering analysis provided an accurate representation of the current genetic relationships among the breeds. Determining coancestry is useful for analysing genetic diversity distribution between and within breeds and provides a good framework for jointly analysing molecular markers and pedigree information. An integrated analysis was undertaken to obtain information on the population dynamics in western Mediterranean native horse populations, and to better determine conservation priorities. 相似文献
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Between-breed genetic diversity is classically considered as a major criterion to be taken into account when setting priorities for conservation of domestic animal breeds. However, it has been argued that methods based on the between-breed component of genetic diversity may not be optimal because they ignore the within-breed component of variation. The paper considers the most common methods used to evaluate those two components when genetic diversity is evaluated on the basis of genetic markers, and proposes to define an aggregate diversity combining linearly the two components. This implies defining for each breed (or population) its contributions to the between-breed and to the within-breed diversity. When defining an aggregate diversity, one can weight these contributions by FST and 1−FST, respectively, since the fixation index FST of Wright represents the proportion of the total genetic variation which is due to differences in allelic frequencies between populations. Such an approach is valid when the objective is genetic improvement by selection within a so-called “meta-population”. However, in a more general context of animal breeding, when heterosis and complementarities between breeds have to be considered, as well as adaptation to specific environments, more weight should be given to the between-breed variation. The proper weight to apply may require solutions adapted to each particular situation. In a long-term conservation perspective, priorities should also take into account the degree of endangerment of each breed. By combining diversity contributions and probability of extinction, a cryopreservation potential (or priority) may be estimated for each breed. The problem is illustrated on a sample of 11 European pig breeds typed for 18 microsatellite loci. 相似文献
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Line Sass Kierkegaard Linn Fenna Groeneveld Anne Kettunen Peer Berg 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2020,69(1-2):2-24
ABSTRACTThe Nordic countries are committed to conserving farm animal genetic diversity. National reports on phenotypic and genetic characterization point towards a lack of characterization for many Nordic native breeds. Little to no knowledge on the traits of the animals and their derived products leads to potential remaining untapped. The objective of this study was to provide a quantitative assessment of phenotypic and genetic characterization of Nordic native breeds, through a literature search and obtaining census data. Six species and a total of 85 breeds were included. Studies were classified according to six different categories of characterization. Results showed that a large percentage of the breeds are not characterized at all. Moreover, most breeds have extremely low census sizes. A substantial effort to increase population sizes and document characteristics of Nordic native breeds, to promote conservation and sustainable use, is needed. 相似文献
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M.-L. Glowatzki-Mullis J. Muntwyler E. Bäumle & C. Gaillard 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2009,126(2):164-175
There is constant pressure to improve evaluation of animal genetic resources in order to prevent their erosion. Maintaining the integrity of livestock species as well as their genetic diversity is of paramount interest for long-term agricultural policies. One major use of DNA techniques in conservation is to reveal genetic diversity within and between populations. Forty-one microsatellites were analysed to assess genetic diversity in nine Swiss sheep breeds and to measure the loss of the overall diversity when one breed would become extinct. The expected heterozygosities varied from 0.65 to 0.74 and 10.8% of the total genetic diversity can be explained by the variation among breeds. Based on the proportion of shared alleles, each of the nine breeds were clearly defined in their own cluster in the neighbour-joining tree describing the relationships among the breeds. Bayesian clustering methods assign individuals to groups based on their genetic similarity and infer the number of populations. In STRUCTURE, this approach pooled the Valais Blacknose and the Valais Red. With BAPS method the two Valais sheep breeds could be separated. Caballero & Toro approach (2002) was used to calculate the loss or gain of genetic diversity when each of the breeds would be removed from the set. The changes in diversity based on between-breed variation ranged from −12.2% (Valais Blacknose) to 0% (Swiss Black Brown Mountain and Mirror Sheep); based on within-breed diversity the removal of a breed could also produce an increase in diversity (−0.6% to + 0.6%). Allelic richness ranged from 4.9 (Valais Red) to 6.7 (Brown Headed Meat sheep and Red Engadine Sheep). Breed conservation decisions cannot be limited to genetic diversity alone. In Switzerland, conservation goals are embedded in the desire to carry the cultural legacy over to future generations. 相似文献
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The genetic diversity of the Red Bororo and White Fulani cattle breeds of Cameroon and Nigeria was assessed with a panel of
32 markers. Estimates for the various indices of genetic diversity, total number of alleles (TNA), mean observed number of
alleles (MNA), mean effective number of alleles (MNE), observed heterozygosity (H
ob) and expected heterozygosity (H
ex), were higher at microsatellite loci than at protein loci. Mean H
ex values were above 71% at microsatellite loci in all the breeds and ranged from 37% to 41.6% at milk protein loci and from
40.9% to 45.6% at blood protein loci. The highest TNA and MNA of microsatellites were recorded for the Nigerian White Fulani.
MNE of milk protein loci was highest in the Cameroonian Red Bororo, while TNA of blood protein loci was highest in the Cameroonian
White Fulani. The high genetic diversity levels indicate the presence of the necessary ingredients for improvement breeding
and conservation. Multi-locus estimates of within-population inbreeding (f), total inbreeding (F) and population differentiation (θ) of the breeds were significantly different from zero, except for θ of blood proteins.
A high level of gene flow was found between the breeds (5.829). The phylogenetic relationship existing among the four breeds
is greatly influenced by location. The high gene flow between the breeds may lead to a loss of genetic diversity through genetic
uniformity and a reduction in opportunities for future breed development. We propose an improvement scheme with aims to prevent
loss of genetic diversity, improve productivity and reduce uncontrolled genetic exchanges between breeds. 相似文献
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J. Aranguren‐Mendez J. Jordana M. Gomez 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2002,119(4):256-263
The genetic diversity of most livestock species is being reduced, and it is not possible to preserve all of these livestock breeds. In order to preserve as much of the genetic diversity as possible, we must first have a robust method of measuring genetic diversity among breeds. Three different methods of study that graphically represent relationships among breeds are presented; Weitzman's method, principal component analysis (PCA) and a neighbour‐joining tree with allele sharing. Diversity was evaluated on the basis of 15 microsatellite markers typed over a total of 513 DNA samples collected from five Spanish donkey breeds. Breed differentiation was confirmed by the clustering based on the genetic distances between individuals, which essentially grouped all individuals in discrete clusters. The genetic distance among breeds was used to measure the global diversity of the set in breeds considered, and to evaluate the marginal loss of diversity attached to each breed. The Catalana breed appeared to be the most ‘unique’ in the set considered. In addition to this, the usefulness of global evaluations of diversity using molecular markers to choose breeds is worthy of conservation. 相似文献
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Using expected allele number as objective function to design between and within breed conservation of farm animal biodiversity 总被引：4，自引：0，他引：4
H. Simianer 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2005,122(3):177-187
Conservation of genetic diversity in farm animal species can be achieved by preventing extinction of breeds and by reducing genetic drift within breeds. It is suggested to use the expected number of alleles segregating in the species after a given time period as objective function in the design of conservation strategies. A formal approach is presented to predict this quantity based on marker information, accounting for extinction probability of breeds and effective population size within breeds as the major component of genetic drift. Based on this model, relative efficiency of different strategies of diversity conservation can be quantified. Formulas are given to derive the marginal expected number of alleles with respect to genetic drift within population and extinction probability, respectively. The suggested approach is illustrated with an example of 13 European cattle breeds. With the assumed parameters, drift is shown to be the major force leading to loss of alleles, and different breeds are prioritized for activities to reduce risk of extinction and for measures to reduce genetic drift, respectively. Although different aspects of the model need to be further refined, the suggested methodology provides a general and flexible tool to derive the optimum conservation strategy in various scenarios. 相似文献
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试验旨在研究浦东白猪现存群体的遗传多样性及其繁殖性能变化的原因。利用全基因组范围内的遗传标记（SNPs）,对比6个太湖流域地方品种及3个西方引进品种,对浦东白猪的遗传多样性进行了分析。同时利用落入繁殖候选基因内的SNPs,分析了群体的多样性及结构。结果显示,相较于本研究中所选择的太湖流域地方品种及西方引进品种,浦东白猪的遗传多样性较太湖流域地方品种低;除枫泾猪外,浦东白猪繁殖相关SNPs的多态性标记的比例、期望杂合度最低,等位基因丰度仅高于杜洛克猪;主成分分析（PCA）结果揭示浦东白猪繁殖相关SNPs位点仍具有其群体独特性。研究结果揭示了浦东白猪现存群体遗传多样性较低,繁殖性能的退化可能是由于一些有利等位基因的灭绝、繁殖相关基因多态性及个体杂合性的降低所致。但是浦东白猪仍然携带一定数量的有利等位基因且依旧具有其群体独特性,暗示浦东白猪仍具有较高的保种价值。本研究为浦东白猪后期的选育、保种和开发利用提供了一定的参考。 相似文献
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选用来源于牛和绵羊的27个微卫星DNA标记,对山东省4个地方山羊品种进行遗传多样性分析,通过计算等位基因频率、多态信息含量、不同标记的平均杂和度、总群体杂合度、亚群体杂合度、群体杂合度、基因分化系数、不同群体的F-统计量、基因流动数、不同群体间的基因流动个数和遗传距离并进行聚类分析,评估其种内变异和种间变异的关系,以群体平均杂合度、F-统计量和遗传分化系数为基础,结合四个山羊种群的实际生存状况,提出避免近交和种群间杂交符合山东山羊种群实际状况的保种模式。研究结果可为山东地方种质特性研究提供基础数据,为山东地方山羊种群的合理保护利用提供科学依据。 相似文献
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XIAO Qian ZHANG Zhe SUN Hao ZHANG Xiang-zhe SHEN Da-de CHU Ye-gen WANG Qi-shan PAN Yu-chun 《中国畜牧兽医》2017,44(4):1095-1101
This study was aimed to investigate the genetic diversity and the reason for the degradation of the reproductive performance of Pudong White pig. The genetic diversity of Pudong White pig, six Taihu pig breeds and three Western pig breeds were analyzed based on the genome-wide SNPs.The genetic diversity and population structure of these pig breeds were also explored based on the SNPs related to reproductive traits. The results showed that Pudong White pig displayed a lower level of the genetic diversity than the Taihu area pig breeds. For the reproductive-related loci, except for Fengjing pig, Pudong White pig displayed the lowest propotion of polymorphic markers, expected heterozygosities and allelic richness (excluded Duroc pig). The result of PCA showed that Pudong White pig displayed its uniqueness in the reproductive-related SNPs. With the comparsion of Taihu pigs and Western populations, Pudong White pig displayed a lower level of the genetic diversity and more homozygous reproductive-related loci. Nevertheless, a certain number of favorable alleles were still harbored in Pudong White pig, which might result high heterosis in the offsprings. In conclusion, the results of this study might provide some valuable information for the breeding, conservation and utilization of this breed. 相似文献
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近年来,高通量测序技术的规模化应用及生物信息技术的普及,极大地推动了家畜基因组学的发展,实现了分子育种标记全基因组水平的快速、精准定位,为全基因组选择育种奠定了重要基础。数千年来的驯化和选择,形成了用途多样的山羊品种,如乳用、皮用、绒用及肉用等,为人类提供了丰富的生产和生活资料。国内外学者采用高通量测序技术对山羊的遗传多样性及生产性能的遗传机制进行了研究,以期找到与山羊种质特性相关的基因,从而为山羊的遗传改良提供新的标记。作者对近五年来基于高通量测序技术研究山羊的遗传多样性和产绒、产奶、繁殖等生产性状的研究进展进行了综述,以期为评估山羊优良种质特性和与生产性状相关的优异基因定位的工作提供参考。 相似文献
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Recently, the widespread use of high-throughput sequencing technology and the development of bioinformatics have been greatly contributed to the development of farm animal genomics. Whole genome-wide analysis can facilitate the fine mapping of the molecular markers related to the production traits quickly and accurately, thus providing an important theoretical basis for genome selection breeding. Several thousand years of domestication and artificial selection produce many modern goat breeds with high production of milk, fiber, and meat, which become abundant production and living materials for human populations. Researchers have studied the genetic diversity and molecular mechanisms of production traits in goats using high-throughput sequencing technology, in order to identify candidate genes related to the excellent germplasm reliable markers for genetic improvement. In this review, we summarized the five-year research progress on the genetic diversity and production traits of goats including fiber, milk production and reproduction traits, mainly based on high-throughput sequencing technology. This paper provides a reference for the evaluation of the excellent goat genetic resources and the investigation of production trait related genes. 相似文献