长江中游草鱼天然种群的生化遗传结构及变异

采用淀粉或聚丙烯酰胺凝胶电泳方法分析了长江中游武汉江段草鱼天然种群(n=81)中10种同工酶约28个基因座位的遗传变异型。该种群的多态座位比例为16.7%,平均杂合度为0.0739。而Utter和Folmar(1978)曾报道美国的5个草鱼人工繁殖种群的多态座位比例及平均杂合度分别为6%和0.021。比较结果表明,近交很可能是导致草鱼人工繁殖种群中遗传变异性降低的主要原因。我们认为生产上采用数量大、来源广的亲鱼进行人工繁殖,并定期用天然种群更换或补充繁殖用亲鱼很可能是保持或增加鱼类人工繁殖种群遗传变异性的一种有效手段。     

中华鲟天然群体蛋白质水平遗传多样性贫乏的初步证据

为阐明我国Ⅰ级珍稀水生保护动物中华鲟天然群体的遗传结构和遗传多样性特征,为其资源的监测量民保护提供科学依据,采用聚丙烯酰胺梯度凝胶电泳技术对中华鲟天然群体进行了蛋白质遗传多态性研究。共研究了１５种蛋白质,有４种蛋白无活呈活性很低,在有活性的１１种蛋白中人测得２６个座位;在２６个座位中,只有１个座位（ＭＤＨ－１）为多态座位。中华鲟多态座位比例（Ｐ）为３．９０％,遗传杂合度（Ｈ）为０．０４,均远远低于     

中华鲟天然群体蛋白质水平遗传多样性

为了阐明我国Ⅰ级珍稀水生保护动物中华鲟(Acipenser sinensis)天然群体的遗传结构和遗传多样性特征,为其资源的监测与保护提供科学依据,采用聚丙烯酰胺梯度凝胶电泳技术对中华鲟天然群体进行了蛋白质遗传多态性研究。共研究了15种蛋白质,有4种蛋白无活 性或活性很低,在有活性的11种蛋白中共测得26个座位;在26个座位中,只有1个座位(MDH-1)为多态座位。中华鲟多态座位比例(P)为3.90%,遗传杂合度(H)为0.04,均远 远低于其他鱼类P和H值的平均水平,说明中华鲟在蛋白质水平上的遗传变异较贫乏,与其他鲟鱼类的情况类似。     

真鲷自然群体和人工繁殖群体的遗传多样性

采用RAPD技术对真鲷野生群体及人工繁殖群体各23个个体进行了DNA多态性检测。实验选取OPK组16个10 bp随机引物用于两群体的遗传多样性分析。在野生群体和人工繁殖群体中分别获得131和123条扩增片段,两群体的多态片段比例分别为62.60%和54.47%,平均杂合度分别为0.4786和0.3633,可见真鲷野生群体及人工繁殖群体的遗传多样性较为丰富,在选择育种和遗传改良方面具有较大的潜力。人工繁殖群体的多态片段比例和平均杂合度都低于野生群体,意味着在生产过程中要采取行之有效的管理保护措施以避免或减少遗传多样性水平的降低,确保真鲷增养殖业的可持续发展。     

人工与自然恢复条件下地被层优势种大羽藓的遗传多样性比较

基于随机扩增多态性DNA(RAPD)方法比较了川西米亚罗地区3个人工云杉林样地和3个天然次生林样地大羽藓(Thuidium cym bifolium)种群的遗传多样性及分化程度。人工林种群的平均多态位点百分比(PPL)为12.7%,Ne i’s基因多样性(HE)为0.042,Shannon’s信息指数(S)为0.064,种群内遗传一致度(I)为0.952;天然次生林种群则依次为10.0%、0.027、0.043和0.960。人工林种群和天然次生林种群Gst分别为0.592和0.702,Fst分别为0.639和0.695;结合UPGMA聚类和PCA分析,发现种群间的基因交流极少。单因素方差分析显示,人工林下大羽藓种群的遗传多样性水平显著高于天然次生林下种群(p<0.05),表明在皆伐迹地上通过人工造林能有效地促进林下物种遗传多样性的恢复。     

宽翅曲背蝗两个地理种群等位酶的比较

采用水平淀粉凝胶电泳技术及应用等位酶分析方法,研究我国河北黄骅、辽宁葫芦岛宽翅曲背蝗两个自然种群的遗传多样性和遗传分化。在检测的11种酶15个酶基因座位中,Adk-I、Fbp-I、Mdh-2和G3pd-I基因座位的等位基因少,而Fbp-2、Mdh-I和Me-I基因座位的等位基因多。对每个基因座位的各基因型进行χ^2检验,除Mdh-I在辽宁葫芦岛种群、Adk-I在河北黄骅种群分别符合Hardy-Weinberg平衡外,其余绝大多数基因座位的基因型频率显著偏离Hardy-Weinberg平衡。两个种群之间存在明显的遗传多样性和分化：多态位点百分率分别为100％和93．3％,等位基因平均数分别为3．1和2．5,平均杂合度观测值分别为0．086和0．061。与其他非迁飞性蝗虫如中华稻蝗(Oxya chinensis)比较,这种蝗虫种群的平均杂合度较低但遗传多态性较高。结果表明：该蝗虫较强的跳跃能力可使个体暴露于各种不同环境,有利于维持种内遗传多态性的动态平衡,而种群保持较高的遗传多态性能增强该物种在不同栖息地的生存和繁殖能力。F-统计量表明两个种群之间的遗传分化相对较小,但这种分化显著高于迁飞性蝗虫如东亚飞蝗(Locusta migratoria manilensis)。Nei的遗传一致度(I)和Roger的遗传距离(D)的结果分析揭示了两个种群之间较高的遗传一致度(I=0．904)和较小的遗传距离(D=0．256)。然而,在一些酶基因座位如Aep-I(Fst=0．462)和Pgi-I(Fst=0．182),F-统计值相对较大,遗传分化比较明显。     

濒危植物猪血木人工繁殖幼苗的遗传多样性及对种群复壮的启示

猪血木为山茶科特有的单型属珍稀濒危植物,目前仅在广东省阳春市八甲镇有分布,且种群数量不足200株,为给濒危植物猪血木的种群成功回归自然和种群复壮提供科学依据,采用AFLP分子技术,对7个种源人工繁殖的猪血木幼苗遗传多样性进行研究。结果表明:6对引物共检测到位点数为115个,其中多态位点数为68个,多态位点所占比率为59.13%,观察等位基因数(Na)为1.5826、有效等位基因数(Ne)为1.3813、Nei′s基因多样性(H)为0.2215、Shannon多样性指数(Ⅰ)为0.3280。UPGMA聚类将7个种源的幼苗划分为3支,不同种源间幼苗的遗传距离与种源地理距离存在显著相关性(P<0.05)。说明不同种源人工繁殖猪血木幼苗仍保持较高的遗传多样性。建议采集不同种源种子进行人工繁殖和人工种群构建,促进物种的种群复壮。     

湘西盲高原鳅群体同工酶分析

采用聚丙烯酰胺凝胶电泳(PAGE)对洞穴鱼类--湘西盲高原鳅(Triplophysa xiangxiensis)群体遗传多样性进行了研究.对其肌肉、心脏、肝脏、脑、脾脏和肾脏等6种组织中的乳酸脱氢酶(LDH)、苹果酸脱氢酶(MDH)、苹果酸酶(ME)、酯酶(EST)、醇脱氢酶(ADH)、谷氨酸脱氢酶(GDH)和葡萄糖-6-磷酸脱氢酶(G-6-PDH)等7种同工酶进行分析,检测到26个座位,其中多态座位4个(Ldh-3、Ldh-4、s-Mdh、m-Mdh),多态座位比例为15.38%,观察杂合度0.0398,预期杂合度0.0411,Hardy-Weinberg遗传偏离指数(D)为-0.0316,存在杂合子缺失.结果表明,湘西盲高原鳅群体群体遗传多样性较低,纯合度较高.     

承德大窝铺不同海拔与群落类型天然油松种群遗传多样性

利用ISSR技术分析了河北承德大窝铺3个不同海拔、4个不同群落类型的油松天然种群的遗传多样性与遗传分化,探讨了天然油松种群遗传多样性与主要生态因子的关系.结果表明:天然油松种群具有较高的遗传多样性,13个筛选出的随机引物共检测出180个位点,总多态位点比率分别达到73.33％和91.11％.海拔影响油松种群的遗传多样性,中海拔( 1070～1130 m)高于高海拔(1230 ～1350 m)和低海拔(910 ～970 m)(多态位点比率分别为63.33％、51.67％和59.44％);群落类型与种群的基因组结构变异之间存在一定的内在联系.遗传变异多来自种群内部(分别为90.45％和75.22％),种群分化不明显;群落类型对天然油松种群间遗传变异和基因交流(Gst为0.248,Nm为1.517)的影响高于海拔对其影响(Gst为0.095,Nm为4.738).可以认为,群落类型对大窝铺天然油松种群遗传分化有较大影响.     

独龙牛遗传多样性及其种群遗传结构的等位酶分析

采用水平片淀粉凝胶电泳技术,进行３０头独牛牛４１种蛋白质共计４４个遗传座位的等位酶分析,只在Ｔｒ,Ｈｐ,Ａｍｙ,Ｅｓｔ等４个座位发现多态性。每个座位等基因的平均数、多态座位百分比和平均杂合度值分别为Ａ＝１．０９０９、Ｐ＝０．０６８２和Ｈ＝０．０２６２。贡山县和福贡县独龙牛群体从酶基因的角度上看遗传多样性贫乏,可能是分别由小种群引种而来,受到瓶颈效应的作用,并伴随着创立者事件的发生。我们结合独龙牛在     

Randomly amplified polymorphic DNA analysis of four different populations of the Indian major carp, Labeo rohita (Hamilton)

The level of genetic variation provides the raw material for selective improvement of a stock. Random amplified polymorphic DNA (RAPD) assay was used to assess the genetic variation in three rivers: the Halda, the Jamuna and the Padma as well as in one hatchery population of the commercially important Indian major carp, Labeo rohita. RAPD markers were amplified from DNA samples of 35 fish from each of the four populations using six decamer random primers. The polymorphic loci proportions were 0.33, 0.28, 0.28 and 0.26 and Nei's gene diversity values were 0.06, 0.07, 0.06 and 0.05 for the Halda, the Jamuna, the Padma and the hatchery populations, respectively. The pairwise population differentiation (F_ST) values indicated a low level of genetic differentiation between the population pairs. From the unweighted pair group method of arithmetic mean (UPGMA) dendrogram based on Nei's genetic distances a correlation between genetic affinities and geographical area was found. The populations were segregated into two groups: the Halda in one group and the Jamuna, the Padma and the hatchery in another group. Overall, the RAPD technique can be introduced as a tool in the population genetics of the rohu fish to provide information on their genetic stock structure.     

三峡库区5 个鲢群体遗传变异的微卫星分析

研究利用10 个高度多态的微卫星标记对三峡水库秭归、巫山、云阳、忠县、木洞等5 个库区鲢(Hypophthalmichthys molitrix)的野生群体进行了遗传多样性分析。检测到161 个等位基因, 群体共有等位基因84 个, 每个微卫星位点的等位基因数729 不等。平均观测杂合度Ho 为0.7840.846, 平均期望杂合度He 为0.8280.847, 平均多态信息含量PIC 为0.7970.817。Fst 值为-0.0010.009, 表明5 个鲢群体间没有遗传分化。Hardy-Weinberg 平衡检验表明巫山、云阳、木洞群体在一些位点上偏离遗传平衡。Bottleneck 分析显示长江三峡库区江段的鲢群体可能在历史上经历了遗传瓶颈。5 个群体间的遗传相似系数为0.8910.950, 遗传距离为 0.0500.115, 根据 Nei's 遗传距离所绘制的聚类图, 表明鲢群体间的遗传距离与其地理距离基本一致。贝叶斯分析结果也证实三峡库区5 个鲢群体可视为一个类群。尽管没有检测到遗传分化, 数据清晰地表明三峡库区的鲢群体仍有很高的遗传多样性, 研究结果为三峡地区和长江上游的鲢种质资源保护和种群评估提供了参考。       

青鱼野生与养殖群体遗传变异的微卫星分析

研究利用自主开发的12个微卫星标记, 对来自于长江水系4个野生群体(湖北石首、湖南湘江、江苏邗江、浙江嘉兴)和1个养殖群体(江苏吴江)青鱼(Mylopharyngodon piceus)进行遗传多样性和遗传结构分析。遗传多样性分析结果显示这12个位点多态信息含量(PIC)介于0.660—0.923, 表明这12个位点均具有高度多态性(PIC>0.5)。5个群体的平均等位基因数(N_a)介于7.917—11.667, 平均有效等位基因数(N_e)介于4.837—6.035; 平均观测杂合度介于0.713—0.861; 平均期望杂合度介于0.749—0.819; 平均多态信息含量介于0.711—0.788, 表明这5个群体均具有较高的遗传多样性。遗传距离分析结果表明4个野生群体之间遗传距离较近, 养殖群体与这4个野生群体遗传距离均较远。UPGMA系统进化树显示, 湘江群体和石首群体首先聚为一支, 然后与邗江群体和嘉兴群体聚为一支, 最后与吴江养殖群体聚为一支。这12个微卫星位点具有较为丰富的遗传多样性特征, 可以用于青鱼不同群体的种质资源的评估和遗传多样性的分析。     

Genetic variation of wild and hatchery populations of the catla Indian major carp (Catla catla Hamilton 1822: Cypriniformes, Cyprinidae) revealed by RAPD markers

Genetic variation is a key component for improving a stock through selective breeding programs. Randomly amplified polymorphic DNA (RAPD) markers were used to assess genetic variation in three wild population of the catla carp (Catla catla Hamilton 1822) in the Halda, Jamuna and Padma rivers and one hatchery population in Bangladesh. Five decamer random primers were used to amplify RAPD markers from 30 fish from each population. Thirty of the 55 scorable bands were polymorphic, indicating some degree of genetic variation in all the populations. The proportion of polymorphic loci and gene diversity values reflected a relatively higher level of genetic variation in the Halda population. Sixteen of the 30 polymorphic loci showed a significant (p < 0.05, p < 0.01, p < 0.001) departure from homogeneity and the F(ST) values in the different populations indicated some degree of genetic differentiation in the population pairs. Estimated genetic distances between populations were directly correlated with geographical distances. The unweighted pair group method with averages (UPGMA) dendrogram showed two clusters, the Halda population forming one cluster and the other populations the second cluster. Genetic variation of C. catla is a useful trait for developing a good management strategy for maintaining genetic quality of the species.     

Genetic differentiation among common and selected hatchery populations of flounder: Evidence from RAPD markers

Randomly amplified polymorphism DNA (RAPD) analysis was performed in order to evaluate one common population and two selected hatchery populations of flounder Paralichthys olivaceus. A total of 90 individuals belonging to three populations were screened using 12 different RAPD primers. A total of 71 loci were produced in the three studied populations, and 43.5%, 42.4% and 42.2% of these loci were polymorphic over all the genotypes tested in common, susceptible and resistant populations, respectively. The number of loci detected by single primers ranged from four to eight. The average heterozygosites of common, susceptible and resistant populations were 0.112, 0.103 and 0.111, respectively. Compared with the common population, the two selected hatchery populations, susceptible and resistant, showed some genetic differences including a smaller number of loci, a smaller number of polymorphic loci, a smaller number of genotypes and a smaller Shannon index. The present study confirmed that it is important to detect the genetic variability of the selected hatchery population for the conservation of natural flounder resources.     

人工雌核发育鲢的遗传多样性及异源遗传物质整入的RAPD分析

运用RAPD技术对连续二代人工雌核发育鲢的遗传多样性及异源遗传物质的整入进行了分析 ,结果表明 :一代雌核发育鲢 ,个体间遗传相似度为 0 94 5— 0 995 6 ,多样性指数为 0 175 ;二代雌核发育鲢 ,个体间遗传相似度为0 96 15— 1 0 0 ,平均为 0 985 2 ,多样性指数为 0 0 6 2。研究揭示经过连续二代人工雌核发育后 ,其遗传多样性明显减少 ,种质进一步纯化。通过对雌核发育鲢二代、亲本鲢和雄鲤的RAPD扩增比较 ,发现雌核发育鲢含有少数与父本相同的特异DNA扩增带 ,而亲本鲢没有 ,在基因水平上表明雌核发育鲢整入了雄鲤的遗传物质     

Comparative genetic diversity of wild and hatchery-produced Pacific oyster (Crassostrea gigas) populations in Korea using multiplex PCR assays with nine polymorphic microsatellite markers

The Pacific oyster, Crassostrea gigas, is the most important and valuable commercial fishery species in Korea. Its farming started 20 years ago and is still rapid expansion in Korea. In this study, to maintain the genetic diversity of this valuable marine resource, possible genetic similarity and differences between the wild population and hatchery population in Tongyeong, Korea were accessed using multiplex assays with nine highly polymorphic microsatellite loci. A total of 250 different alleles were found over all loci. Despite a long history of hatchery practices, very high levels of polymorphism (mean alleles = 22.89 and mean heterozygosity = 0.92) were detected between the two populations. No statistically significant reductions were found in heterozygosity or allelic diversity in the hatchery population compared with the wild population. However, significant genetic heterogeneity was found between two populations. These results provide no evidence to show that hatchery practice of Pacific oyster in Korea has significantly affected the genetic variability of the hatchery stock. Although further studies are needed for comprehensive determinations of the hatchery and wild populations with increased number of Pacific oyster sample collections, information on the genetic variation and differentiation obtained in this study can be applied for genetic monitoring of aquaculture stocks, genetic improvement by selective breeding and designing of more efficient conservation management guidelines for these valuable genetic materials.     

Sixteen polymorphic microsatellites in bighead carp (Aristichthys nobilis) and cross-amplification in silver carp (Hypophthalmichthys molitrix)

A (GT)(n) enriched partial genomic library of bighead carp (Aristichthys nobilis) was constructed by employing the (fast isolation by AFLP of sequences containing repeats) FIASCO protocol. Sixteen loci exhibited polymorphism with two to seven alleles/locus (mean 3.263) in a test population and the observed heterozygosity ranging from 0.100 to 0.690 (mean 0.392). Eleven of the 16 bighead carp microsatellites were found to be also polymorphic in silver carp. These polymorphic loci should provide sufficient level of genetic diversity to evaluate population structure of bighead carp.     

长江水系钱草鱼遗传结构及变异性的RAPD研究

采用随机扩增多态性DNA（RAPD）技术对长江中游的湖北嘉鱼与江西瑞昌两个地理群体和中游的汉江和湘江两大水系的鲢和草鱼的群体进行了遗传学研究。发现长江水系链的遗传变异要高于草鱼,与现今生物量成反比的反常现象。鲢遗传多样性从大到小的分布是嘉鱼→湘江→瑞昌→汉江。草鱼遗传多样性从大到小的分布是瑞昌→汉江→湘江→嘉鱼,鲢和草鱼的遗传多样性地理分布并不一致。遗传分化指数Gst分别为12.3%和17.5%,表明鲢和草鱼的四个地理群体的遗传分化度较低,可能与地理较近和基因交流频繁有关。