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1.
千岛湖细鳞鲴和黄尾鲴COI种群遗传结构比较的初步研究   总被引:1,自引:0,他引:1  
利用线粒体COI基因序列,比较了千岛湖水库共栖的细鳞鲴(Xenocypris microlepis)和黄尾鲴(X.davidi)的遗传资源状况。结果显示,在532 bp的一致序列中,黄尾鲴碱基T、C、A、G平均含量分别为27.3%、18.0%、28.7%、26.0%;细鳞鲴分别为25.2%、19.6%、29.3%、25.9%。黄尾鲴种群的变异位点为5个,细鳞鲴种群变异位点为3个。多样性分析显示,黄尾鲴的遗传多样性高于细鳞鲴。在两个物种中各发现4个单倍型,黄尾鲴4个单倍型中,有3个是共享单倍型,而细鳞鲴中仅1个共享单倍型,黄尾鲴富文和临岐群体之间存在显著的分化(Fst=0.048 09),细鳞鲴汾口群体和富文(Fst=0.238 10)、临岐群体(Fst=0.260 72)之间存在显著的遗传分化。单倍型的NJ树将四个单倍型分为两个支,推测可能是由于二次迁入或者多样性丧失导致。  相似文献   

2.
对中国东南沿海福建平潭和广东汕头、闸坡3个群体38 ind三线矶鲈(Parapristipoma trilineatus)线粒体控制区的914 bp序列进行分析,发现22个变异位点,共有33个单倍型。3个群体总体的单倍型多样性和核苷酸多样性均较高(H=0.991 0±0.009,π=0.005 8±0.000 4),其中平潭和汕头群体分别表现出最低和最高的核苷酸多样性(π=0.004 9±0.000 5和0.006 6±0.000 9)。3个群体间的Fst值为0.056 6~0.105 3,Nm值为4.248 3~8.333 4,表明3个群体间存在较低分化,可作为1个管理单位进行保护,建议优先保护汕头群体。在简约性网络图中单倍型呈星状分布,中性检验Fu’s Fs为显著负值和核苷酸不配对分析呈现单峰分布,表明三线矶鲈在历史上经历过种群扩张事件,推测扩张年代约为晚更新世的9.81~2.45万年前。  相似文献   

3.
在测定的采自广东饶平、阳江和广西东兴海域的62尾康氏马鲛(Scomberomorus commerson)线粒体COI基因711 bp序列中,共检测到26个变异位点,18个单倍型,总体呈现出高单倍型多样性(Hd=0.808±0.040)和低核苷酸多样性(π=0.004 0±0.000 6)的特点。邻接树上出现了3个分支,分支间Fst为0.811~0.833且P0.001,Nm为0.1~0.117;AMOVA分析显示分支间遗传变异占82.61%。表明3个分支间分化程度高,推测分歧时间为(89~22.67)万年前中更新世时期,可能原因是受到更新世冰期和间冰期交替的影响。但分支内与分支间都有不同地理来源的个体,没有出现明显的地理聚群;不同地理群体间Fst为-0.027~0.066,Nm均大于4或小于0;群体内个体间变异为96.34%。均表明群体间基因交流频繁,遗传分化程度并不高。3个分支中Clade A分支经历过种群快速扩张事件,可能是末次冰期期间康氏马鲛进入外海并受洋流及生存空间改变的影响。  相似文献   

4.
基于线粒体控制区序列的南海北部近岸鯻的遗传多样性   总被引:1,自引:0,他引:1  
80尾鯻(Therapon theraps)样本采自广东碣石、阳江,广西东兴,海南临高、陵水,测定其线粒体控制区951 bp序列,发现42个变异位点,60个单倍型。南海北部近岸鯻总体的单倍型多样性(0.986±0.007)和核苷酸多样性相对较低(0.009±0.000),其中陵水群体核苷酸多样性最高(0.010),碣石、阳江、东兴群体最低(0.008)。单倍型网络图与邻接树没有形成明显不同的谱系分支和地理聚群,表明不存在谱系结构和地理结构。大陆沿岸碣石、阳江和东兴群体间的遗传分化系数(Fst)为–0.017 5~0.008 9(P0.05),基因流(Nm)值为–14.54~27.84;海南岛临高和陵水群体间Fst为–0.046 0(P0.05),Nm为–5.68,表明大陆沿岸群体内部和海南岛群体内部都无明显分化;但海南岛与大陆群体间的Fst为0.061 6~0.135 3(P0.05),Nm为1.87~3.81。分子方差分析显示,大陆沿岸群体和海南岛群体间分化极显著(FCT=0.100 7,P=0.000 0),可能是受大陆与海南岛分离形成的琼州海峡,全年余流方向总趋势是由东向西,且强度较高的影响。南海北部近岸鯻可作为2个管理单位进行保护,建议优先保护陵水群体。单倍型简约性网络图呈非典型的星状分布,中性检验Fu’s Fs为显著负值且核苷酸不配对分析为单峰分布,表明历史上经历过种群扩张事件,推测扩张年代为晚更新世(3.62万年前),扩张后的有效群体大小约为扩张前的8.7×106倍,可能是受到海退缩减和海侵扩张的影响。  相似文献   

5.
香鱼野生群体和养殖群体遗传多样性比较   总被引:2,自引:2,他引:0  
香鱼是分布于中国、日本和朝鲜的一种珍稀名贵经济鱼类,本实验比较分析了香鱼养殖和野生群体的遗传多样性。研究结果显示,在长度为445 bp的控制区部分序列上,鳌山卫养殖群体的单倍型多样度h(0.198 4±0.092 4)和核苷酸多样度π(0.000 8±0.000 9)显著低于东张水库野生群体(h=0.810 5±0.067;π=0.002 6±0.002 0),两群体产生了较大的遗传分化(F st=0.447,P=0);单倍型邻接关系树的拓扑结构简单,未呈现明显的地理谱系结构,日本香鱼个体与中国香鱼亲缘关系较远;东张群体的历史动态分析结果表明其可能经历过近期的群体扩张事件。无论是养殖群体还是野生群体,中国香鱼群体的遗传多样性现状不容乐观。  相似文献   

6.
宋娜  高天翔  王志勇 《水产学报》2012,36(8):1153-1158
采用线粒体DNA控制区序列比较分析了路氏双髻鲨日照和霞浦群体的遗传结构及遗传多样性现状。研究结果显示:在长度为548 bp的mtDNA控制区序列上,34尾路氏双髻鲨个体仅检测到5个单倍型,两群体均呈现出较低的遗传多样性水平,日照群体的单倍型多样度(h)、核苷酸多样度(π)以及两两序列比较的平均碱基差异数(p)(h=0.6000±0.1305;π=0.0046±0.0031;p=2.5333±1.4856)略高于霞浦群体(h=0.5109±0.0955;π=0.0024±0.0017;p=1.2899±0.8373);邻接关系树显示,5个单倍型明显分为两支,净遗传距离为0.016;群体遗传分化指数为Fst=-0.047(P=0.914),表明两群体之间不存在显著差异,确切P检验结果也表明两群体存在随机交配现象(P=0.731);核苷酸不配对分布呈双峰类型,其中一个峰对应类群内序列差异,另外一个峰对应两个类群序列间差异。研究表明,路氏双髻鲨较小的有效群体导致了较低的遗传多样性,其资源状况已不容乐观。  相似文献   

7.
运用线粒体DNA(mtDNA)控制区部分基因序列测序技术对6个凡纳滨对虾养殖群体(S1、S2、G1、G2、K1和Sg)的遗传多样性和系统进化关系进行了分析.结果显示,在检测到的146个单倍型中,144个为单群体特有,其余两个为群体S1和S2共享.6个群体的单倍型多样性(Hd)为0.42-0.99,核苷酸多样性(π)为0.00-0.08,其中,单倍型多样性最高的是群体K1 (Hd=0.99±0.01),核苷酸多样性最高的是群体S2 (π=0.08±0.04).综合考虑,遗传多样性最低的为群体S1(Hd=0.42±0.08,π=0.00),遗传多样性最高的是群体S2 (Hd=0.88±0.02,π=0.08±0.04).AMOVA分析结果显示,来自群体间的遗传差异(46.98%)略低于来自群体内的遗传差异(53.02%).各群体间的遗传分化Fst值均为正值(0.173-0.974),表明6个群体间存在较大程度的遗传分化差异.基于遗传距离的构建的UPGMA系统进化树和基于单倍型结果构建的NJ聚类图显示,系统进化树主要分为两支:S1和S2群体聚在一起成为一支;G1和G2群体首先聚在一起,再与Sg群体聚在一起,随后与K1群体聚成另一支,6个群体单倍型的聚类关系与遗传距离的进化关系类似.进一步对群体内雌雄群体间遗传差异进行分析发现,同一群体的雌雄群体间遗传多样性水平相近,雌雄群体间基本出现轻微到明显的遗传分化;比较相同群体不同生长速率的个体的遗传参数发现,生长较快群体与生长较慢群体间可能出现一定程度的遗传分化差异;对同一公司不同时间购买的群体分析发现,购买间隔较长(7-9个月)的群体之间的遗传分化值可能会大于不同种虾公司间群体的遗传分化值.  相似文献   

8.
毛蚶三个地理群体生化遗传特征分析   总被引:1,自引:0,他引:1  
利用同工酶技术结合聚丙烯酰胺电泳对江苏海州湾、浙江象山港、辽宁辽东湾三个海区毛蚶群体的同工酶遗传多样性进行了研究。在三个群体的9种同工酶中,共检测到了18个基因位点,海州湾、象山港和辽东湾三个群体的多态位点比率(P.95)分别为61.11%、55.56%、64.71%,平均杂合度观测值(Ho)变化范围在0.1689~0.1770间,位点有效等位基因数分别为1.4417、1.3917、1.4219,遗传多样性较丰富。各群体普遍存在着杂合子缺失现象,近交系数(Fis)分别为0.2140、0.1232、0.1797。比较了三个群体间的遗传分化指数(Fst)和群体每代迁移数(Nm),结果表明,海州湾群体和象山港群体间遗传分化较小,Fst=0.0448;而辽东湾群体与其它两个群体间的遗传分化较大,分别为Fst=0.0755,Fst=0.0812。聚类分析结果同样表明,海州湾群体首先与象山港群体相聚,后与辽东湾群体聚类。讨论了毛蚶群体分化机制,近交系数与繁殖生物学的相关性。  相似文献   

9.
测定了怒江缺须盆唇鱼(Placocheilus cryjotolrtemus)5个群体共138尾个体的线粒体DNA Cyt b基因序列,以探讨群体遗传结构和遗传多样性.结果显示:1 140 bp的Cyt 6基因共检测到21个变异位点,从138个样本中得到21个单倍型,平均单倍型多样性(h)为0.826,核苷酸多样性(π)为0.002.15,遗传多样性水平较低.5个群体中,泸水群体遗传多样性相对最高,保山道街群体最低.计算5群体的Kiinura 2-paramter遗传距离,福贡群体和龙镇桥群体之间的遗传距离最远,为0.003 46;泸水群体和保山道街群体之间的遗传距离最近,为0.000 93.Fu'Fs中性检验和核苷酸不配对分析暗示了缺须盆唇鱼在历史上可能发生过种群扩张.分子方差分析(AMOVA)表明,5群体间总遗传分化系数Fst=0.305 1(P<0.05),群体间具有较高的遗传分化水平.结果说明,怒江缺须盆唇鱼遗传多样性较低,具有较高的遗传分化水平,这可能是由于该物种自身活动能力差以及中游和下游生境明显差异所致.  相似文献   

10.
为了解中国长棘银鲈(Gerres filamentosus)的遗传背景以更好地保护与开发利用种质资源,测定了南海北部7个群体线粒体COⅠ基因5′端序列,以分析其遗传多样性和遗传结构。结果发现,176尾长棘银鲈652 bp序列中有25个单倍型,155个变异位点。7个群体整体呈现较高的单倍型多样性(H_d=0.767±0.018)与较低的核苷酸多样性(π=0.055 0±0.003 7)。就遗传多样性指数而言,碣石群体(H_d=0.606±0.092,π=0.059 2±0.006 6)最高,次高为阳江群体(H_d=0.323±0.102,π=0.027 0±0.010 7);琼海群体(H_d=0.560±0.125,π=0.001 0±0.000 3)最低,次低为陵水群体(H_d=0.685±0.077,π=0.001 5±0.000 3)。群体遗传分化系数F_(st)显示,碣石、阳江群体与其他群体间存在高度(极显著)的遗传分化(F_(st)=0.517 1~0.851 4,P<0.001),这2个群体间有低等程度(显著)的遗传分化(F_(st)=0.111 1<0.15,P<0.05),而其他群体间无明显分化(F_(st)=-0.025 5~0.008 8,P>0.05)。AMOVA分析显示,群体变异主要来源于群体内个体间(61.69%~74.13%),但群组间仍有较多变异(19.06%~37.92%);原因可能与历史上琼州海峡的阻碍、当代复杂的海流以及长棘银鲈只进行短距离洄游等生态特性有关。中性检验显示,海南陵水、东方和新盈群体在晚更新世时期发生过种群扩张,但南海长棘银鲈总体未呈现种群扩张现象,可能是不同谱系的叠加造成整体核苷酸不配对分析图呈现多峰。碣石和阳江群体与其他群体间有高度的遗传分化,可将它们作为一个独立的管理保护单位,其中碣石群体遗传多样性最高,应重点保护;其他群体可作为另一管理保护单位,其中琼海和陵水群体遗传多样性较低,建议及时采取保护措施,避免遗传多样性过度下降而导致资源枯竭。  相似文献   

11.
12.
Growth hormone (GH) and reproduction: a review   总被引:5,自引:0,他引:5  
Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations.  相似文献   

13.
Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China.  相似文献   

14.
The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.  相似文献   

15.
Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg?1 protein) than essential amino acids (425.82 ± 9.15 g kg?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.  相似文献   

16.
17.
The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg–1 fish·h–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g–1·ml–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min–1·g–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min–1·g–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated.  相似文献   

18.
In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.  相似文献   

19.
Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL?1 (1.25 ng well?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation.  相似文献   

20.
  1. Humanity is facing a biodiversity crisis, with freshwater-associated biodiversity in a particularly dire state. Novel ecosystems created through human use of mineral resources, such as gravel pit lakes, can provide substitute habitats for the conservation of freshwater and riparian biodiversity. Many of these artificial ecosystems are subject to a high intensity of recreational use, however, which may limit their biodiversity potential.
  2. The species richness of several taxa (plants, amphibians, dragonflies, damselflies, waterfowl, and songbirds) was assessed and a range of taxonomic biodiversity metrics were compared between gravel pit lakes managed for recreational fisheries (n = 16) and unmanaged reference lakes (n = 10), controlling for non-fishing-related environmental variation.
  3. The average species richness of all the taxa examined was similar among lakes in both lake types and no substantial differences in species composition were found when examining the pooled species inventory. Similarly, there were no differences between lake types in the presence of rare species and in the Simpson diversity index across all of the taxa assessed.
  4. Variation in species richness among lakes was correlated with woody habitat, lake morphology (surface area and steepness), and land use, but was not correlated with the presence of recreational fisheries. Thus, non-fishing-related environmental variables had stronger effects on local species presence than recreational fisheries management or the presence of recreational anglers.
  5. Collectively, no evidence was found that anglers and recreational fisheries management constrain the development of aquatic and riparian biodiversity in gravel pit lakes in the study region; however, the conservation of species diversity in gravel pit lakes could benefit from an increasing reliance on habitat enhancement activities.
  相似文献   

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