鲟鱼种质鉴定方法研究进展

鲟鱼是一类古老的大型经济鱼类,由于过度捕捞和人类对其生态环境的破坏及其鲟鱼自身具有的性成熟时间长、幼体成活率低等特点,使世界范围内的鲟鱼自然资源日趋枯竭。人工养殖鲟鱼已是鲟鱼制品的主要来源,但由于种质来源不清及大量杂交鲟的存在导致种质混乱情况比较严重,目前国内外均未有一套比较完善可行的鲟鱼种质鉴定体系。总结了目前进行鲟鱼种质鉴定的一些常用方法,分析了各个方法的优缺点,为确立一套稳定可靠的鲟鱼种质鉴定方法奠定基础。     

利用超声波技术鉴定幼龄鲟鱼的性别

2006年2月至2008年3月,利用超声波鉴定技术对20 553尾2龄或3龄鲟鱼的性别及成熟度进行了检测,同时对检测并确定性别的鲟鱼随机取样解剖,验证超声波检测结果的准确率,同时追踪检测西伯利亚鲟(Acipenser baerii)的性腺发育过程,获得不同发育时期性腺的超声波图像.超声波性别鉴定技术的准确率与养殖鲟鱼的种类、性腺发育阶段密切相关,本研究结果显示,2龄或3龄西伯利亚鲟的检测准确率为92.0%～100%,2龄俄罗斯鲟(A.gueldenstaedtii)准确率为83.0%,3龄史氏鲟(A.schrenckii)准确率为58.0%;同时,根据超声波图像可较好地了解性腺成熟度,本次检测发现养殖的2龄或3龄西伯利亚鲟性腺发育一般处于Ⅱ～Ⅲ期.超声波鉴定是一项能有效鉴定鲟鱼性别的技术,值得推广.     

分子生物学方法在鲸类学研究中的应用

80年代以来,随着分子生物学的迅猛发展,涌现出一批分子进化和种群遗传分析方法和技术。       

SSR标记在桉树树种精准鉴定中的应用分析

为精准鉴定桉树种质,利用4个在种内完全保守的SSR位点对28种桉树(Eucalyptus)进行鉴定。根据这4个SSR位点的微卫星重复次数和侧翼序列特异核苷酸组合,构建了28种桉树种间种质资源的鉴定条码,能够精准鉴定9种桉树。这为桉树杂交育种工作提供了生物学依据。     

DNA技术在海洋食品物种鉴定中的应用

随着分子生物学技术的发展, 海洋食品物种鉴定方法由原来的蛋白质水平深入到了DNA水平。目前应用于海洋食品物种鉴定的DNA技术主要是FINS(Forensically informative nucleotide sequencing)、PCR-RFLP和物种特异性PCR标记技术等, 能够实现对新鲜、冰冻、腌制或灌装食品物种进行鉴定, 而对混合样本的鉴定及量化分析是尚待解决的一个问题。基因数据库对物种鉴定的影响也越来越大, 是海洋加工食品物种鉴定可利用的另一种重要信息资源。文章综述了DNA技术在海洋食品物种鉴定中的应用研究进展, 并展望DNA技术在海洋食品检测中的发展趋势。     

药用植物DNA条形码鉴定研究进展

DNA条形码是利用相对较短的标准DNA片段对物种进行快速准确鉴定的一门技术。DNA条形码技术可以从分子水平弥补传统鉴定方法的一些不足。该技术具有良好的通用性,使得物种鉴定过程更加快速,已经广泛应用于动物物种的鉴定研究中。近年来,随着药用植物DNA条形码鉴定研究的快速发展,逐渐形成了药用植物和植物源中药材鉴定的完善体系。本文综述了DNA条形码技术鉴定药用植物的原理,介绍了中草药传统鉴定方法及其缺陷、使用DNA条形码技术鉴定植物源药材的意义以及DNA条形码在药用植物鉴定中的应用,对其应用前景进行了展望。     

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。     

水生实验动物剑尾鱼的DNA指纹图谱构建

目的剑尾鱼是由原良种委员会审定并由农业部公布的水生实验动物,在遗传学研究、水环境污染监测、细菌性疾病研究方面显示出较好的应用前景。为了对剑尾鱼选育系进行种质资源监测、区分选育系与非选育以及鉴定近交系纯度,本研究采用微卫星DNA进行水生实验动物剑尾鱼的指纹图谱构建。方法根据相关报道设计合成了50对微卫星引物,对几个剑尾鱼品系的种质资源进行检测,筛选品系间差异性引物;确立剑尾鱼核心引物,用EXCEL散点图绘制DNA指纹图谱模式图;并将数字化指纹数据输入珠江水产研究所鱼类种质鉴定软件V1.0,形成剑尾鱼标准化指纹图谱鉴定数据库。结果共获得剑尾鱼品系间特异标记5个可用于剑尾鱼近交系鉴定,确立46个微卫星标记为核心引物,构建剑尾鱼选育系RR-B系、RW-H系和非选育的野生品种的DNA指纹图谱。结论本研究筛选出的微卫星标记与构建的指纹图谱,可用于剑尾鱼3个品种间的品种鉴定、纯度检测及遗传监测。     

DNA分子标记在药用植物中的应用

对DNA分子标记技术在药用植物鉴定、中药质量标准化、遗传图谱构建和近缘物种进化关系等方面的研究进展进行了综述,并展望了分子标记技术在药用植物研究中的发展前景。     

黄精属植物DNA分子鉴定技术应用研究进展

黄精属植物分布广泛、资源丰富、类群复杂、栽培历史悠久,具有重要的药用、经济、观赏与文化价值.在大健康的时代背景下,黄精作为中国传统中药材,其潜在市场和广泛用途不断受到人们的重视与发掘.随着分子生物学科研究的完善与深入,先后出现了多种基于DNA水平的分子鉴定技术,加速黄精属相关领域的研究并取得了较为丰硕的成果.本文对近年...     

Improved genetic identification of acipenseriform embryos with application to the endangered pallid sturgeon Scaphirhynchus albus

We produced pallid sturgeon Scaphirhynchus albus embryos at five pre-hatch developmental stages and isolated and quantified genomic DNA from four of the stages using four commercial DNA isolation kits. Genomic DNA prepared using the kit that produced the largest yields and concentrations were used for microsatellite DNA analyses of 10–20 embryos at each of the five developmental stages. We attempted to genotype the hatchery-produced embryos at 19 microsatellite loci and confirmed reliable genotyping by comparing the microsatellite genotypes to those of known parents. Embryos at stages 5 and 8 did not produce reliable genotyping while those at stages 14, 24 and 33 did. We used the same DNA isolation method on 262 wild-caught acipenseriform embryos collected from the lower Yellowstone River. A total of 200 of the wild embryos were successfully identified to stages 8 to 34 and the rest could not be staged. Using a combination of single nucleotide polymorphism and microsatellite markers, 249 of the wild-caught embryos were genetically identified as paddlefish Polyodon spathula, five were identified as shovelnose sturgeon Scaphirhynchus platorynchus and eight failed to amplify. None were identified as pallid sturgeon. This study demonstrates that early-stage wild-spawned acipenseriform embryos can be genetically identified less than 24 h post-spawn. This methodology will be useful for recovery efforts for endangered pallid sturgeon and can be applied to other acipenseriform species.     

Polyphyly of mtDNA lineages in the Russian sturgeon, Acipenser gueldenstaedtii: forensic and evolutionary implications

Molecular species identification methods are an important component of CITES monitoring programs for trade in sturgeon and caviar. To date, obtaining molecular evidence for distinguishing caviar from four closely related Eurasian sturgeon species Acipenser baerii (Siberian sturgeon), A. gueldenstaedtii (osetra), A. persicus (Persian sturgeon), A. naccarii (Italian sturgeon) remains problematic. Using approximately 2.3 kb of mtDNA sequence data (cytochrome b, NADH5, control region), we find this to be attributable to the polyphyletic nature of these mitochondrial DNA markers in the Russian sturgeon, A. gueldenstaedtii. Two mitochondrial lineages are present within this species: one is phylogenetically affiliated with A. persicus and A. naccarii, while the other clusters with A. baerii. These findings have a direct impact on molecular testing of commercial caviar and demonstrate the necessity of using large sample sizes when constructing forensic databases. Furthermore, the results affect current taxonomic designations for these species as well as hypotheses concerning their evolutionary origins.     

Mitochondrial DNA sequence variation within and between tuna Thunnus species and its application to species identification

Restriction analysis detected two types of bigeye tuna (α and β); the α type was in the majority in the Atlantic but nearly absent in the Indo-Pacific. The β type shared a larger number of restriction sites with other species than the conspecific β type, but bigeye-specific nucleotide substitutions with a novel diagnostic restriction profile were found. Although the nucleotide sequence difference between Atlantic and Pacific sub-species of the northern bluefin tuna was nearly the largest among species, individuals possessing the Atlantic type of mtDNA were found at very low frequency in the Pacific and vice versa. Previous RFLP markers were found to be diagnostic for the other five species (albacore, blackfin, longtail, southern bluefin and yellowfin tunas). Genetic information is provided to discriminate all Thunnus species regardless of their origin and to identify the ocean of capture in the northern bluefin and bigeye tunas.     

Genetic issues in aquatic species management: the shortnose sturgeon (Acipenser brevirostrum) in the southeastern United States

Anadromous species occupy multiple freshwater,estuarine, and marine habitats, which posesspecial challenges in wildlife management. Inparticular, the level of immigration betweendrainages can be a critical factor in thedefinition of management units and the designof population-specific stocking programs. Thesemi-anadromous shortnose sturgeon (Acipenser brevirostrum) is listed as anendangered species under the Endangered SpeciesAct in the United States. To assess populationstructure in this species as a guide toeffective management, tissue samples werecollected from adult specimens (N = 198) fromfive river systems in the southeastern U.S.,and augmented with a sample from New Brunswick,Canada (N = 13), the extreme northern end ofthe species' range. Comparisons of mtDNAcontrol region sequences reveal a shallow genegenealogy and modest, but significant,population structuring (_st = 4.3%or _st = 17.7% when Canadian samplesare included). Populations inhabiting riversystems in the southeastern U.S. are closelyrelated, a pattern consistent with more recentdivergences along evolutionary timeframes. Haplotype diversity is moderate to high in mostdrainages (h = 0.383–1.000), exceptfor the Savannah and Edisto rivers, indicatingthat historical levels of mtDNA diversity mightbe largely intact outside of these drainages. Low mtDNA diversity in the Savannah andneighboring Edisto drainages might stem from anexperimental stocking effort during 1984–1992 that depressed overall genetic diversityin the Savannah and established or augmentedthe Edisto River population with a relativelylimited number of matrilines.     

Site heteroplasmy in the mitochondrial cytochrome b gene of the sterlet sturgeon Acipenser ruthenus

Sturgeons are fish species with a complex biology. They are also characterized by complex aspects including polyploidization and easiness of hybridization. As with most of the Ponto-Caspian sturgeons, the populations of Acipenser ruthenus from the Danube have declined drastically during the last decades. This is the first report on mitochondrial point heteroplasmy in the cytochrome b gene of this species. The 1141 bp sequence of the cytb gene in wild sterlet sturgeon individuals from the Lower Danube was determined, and site heteroplasmy evidenced in three of the 30 specimens collected. Two nucleotide sequences were identified in these heteroplasmic individuals. The majority of the heteroplasmic sites are synonymous and do not modify the sequence of amino acids in cytochrome B protein. To date, several cases of point heteroplasmy have been reported in animals, mostly due to paternal leakage of mtDNA. The presence of specific point heteroplasmic sites might be interesting for a possible correlation with genetically distinct groups in the Danube River.     

Verification of meiotic gynogenesis in Siberian sturgeon (Acipenser baeri Brandt) using microsatellite DNA and cytogenetical markers

Diploid gynogenesis was induced in Siberian sturgeon Acipenser baeri using ultra violet (UV)-irradiated bester ( Huso huso × Acipenser ruthenus ) sperm. The higher survival rate of meiotic diploids was noted after 1350 ergs mm⁻² UV irradiation. A total of 80 meiotic diploids of known parentage from two different experimental treatments were screened using microsatellite DNA and cytogenetical analysis, and uniparental transmission in meiotic diploids was confirmed.     

Gender identification of shovelnose sturgeon using ultrasonic and endoscopic imagery and the application of the method to the pallid sturgeon

Monthly sampling of shovelnose sturgeon Scaphirhynchus platorynchus , a biological surrogate for the endangered pallid sturgeon Scaphirhynchus albus , was conducted to develop a multi‐seasonal profile of reproductive stages. Data collected included histological characteristics of gonads from wild caught fish and laboratory and field ultrasonic and endoscopic images. These data were used to compare effectiveness of ultrasonic and endoscopic techniques at identifying gender of adult shovelnose sturgeon at different reproductive stages. The least invasive method ( i.e . ultrasound) was least effective while the most invasive ( i.e . endoscope through an abdominal incision) was the most effective at identifying shovelnose sturgeon gender. In most cases, success rate for identifying males was greater than females, with success at identifying both genders greater in more advanced reproductive stages. Concomitantly, for most months average reproductive stage was more advanced for males than females. April and May were the months with the most advanced reproductive stage, and were the months when ultrasound was most effective. Methods were also applied in the Upper Missouri River to validate their use on pallid sturgeon Scaphirhynchus albus . Ultrasound was successful at identifying pallid sturgeon gender, however, endoscopic examination through the urogenital duct was only successful at identifying pallid sturgeon gender when the urogenital duct was not opaque.     

Biology and conservation of sturgeon and paddlefish

The Acipenseriformes (sturgeon and paddlefish)live in the Northern Hemisphere; half of thesespecies live in Europe, mostly in thePonto-Caspian region, one third in NorthAmerica, and the rest in East Asia and Siberia.They reproduce in freshwater and most of themmigrate to the sea, either living in brackishwater (Caspian, Azov, Black and Baltic Seas) orin full seawater on the oceanic continentalshelf. Most species feed on benthic organisms.Puberty usually occurs late in life (5–30 yearsof age) and adult males and females do notspawn on an annual basis. Adults continue togrow and some species such as the beluga (Huso huso) have reached 100 years of age andmore than 1,000 kg weight. Stocks of sturgeonsare dramatically decreasing, particularly inEurasia; the world sturgeon catch was nearly28,000 t in 1982 and less than 2,000 t by 1999.This decline resulted from overfishing andenvironmental degradation such as: accumulationof pollutants in sediments, damming of rivers,and restricting water flows, which becomeunfavorable to migration and reproduction.Several protective measures have beeninstituted; for example, fishing regulation,habitat restoration, juvenile stocking, and theCITES listing of all sturgeon productsincluding caviar. In addition, sturgeon farmingpresently yields more than 2,000 t per year(equivalent to wild sturgeon landings) andabout 15 t of caviar. Hopefully, thisartificial production will contribute to areduction of fishing pressure and lead to therehabilitation of wild stocks.