基于形态学差异探讨秦岭细鳞鲑亚种有效性问题

秦岭细鳞鲑(Brachymystax lenok tsinlingensis Li)的亚种分类地位自命名以来一直饱受争议。研究运用单因素方差分析、主成分分析、判别分析、聚类分析及差异系数检验法, 对秦岭细鳞鲑和黑龙江流域的尖吻细鳞鲑(B. lenok lenok)和钝吻细鳞鲑(B. tumensis)的5项可数性状和34项标准化后的比例性状进行统计分析。单因素方差分析结果表明, 尖吻细鳞鲑、钝吻细鳞鲑和秦岭细鳞鲑在32项比例性状和5项可数性状上存在极显著差异(P<0.01); 主成分分析结果显示, 贡献率较大的前3个主成分的累计贡献率为92.779%; 以逐步判别分析方法选用14个判别效果较好的比例性状构建了3个细鳞鲑类群的判别函数, 综合判别率为99.4%。基于欧式距离矩阵法构建的形态学聚类图显示, 秦岭细鳞鲑和尖吻细鳞鲑距离较近, 而与钝吻细鳞鲑距离较远。据Mayr 75%亚种识别和划分规则, 34项比例性状和5项可数性状中, 尖吻细鳞鲑和秦岭细鳞鲑第一鳃弓外鳃耙数目的差异系数大于1.28, 而钝吻细鳞鲑和秦岭细鳞鲑有31项比例性状和2项可数性状的差异系数高于1.28。据分析结果, 结合秦岭细鳞鲑地理隔离的事实及其与尖吻细鳞鲑和钝吻细鳞鲑的形态差异, 推断秦岭细鳞鲑与黑龙江流域内的尖吻细鳞鲑的形态差异程度至少已达亚种水平。     

黑龙江流域两种细鳞鲑的形态学比较及其分类地位初探

对比研究了分布于我国黑龙江流域具钝吻和尖吻两种形态特征的细鳞鲑,其主要形态学性状的显著差异达到种间分化水平.细鳞鲑属Brachymystax在中国应有两个种,分别为图们江细鳞鲑B.tumensis(具钝吻特征)和细鳞鲑B.lenok(具尖吻特征).     

基于线粒体控制区和微卫星标记探讨秦岭细鳞鲑物种有效性

文章基于线粒体控制区基因序列和微卫星标记比较秦岭细鳞鲑(Brachymystax tsinlingensis Li)、黑龙江流域的尖吻细鳞鲑(Brachymystax lenok Pallas)和钝吻细鳞鲑(Brachymystax tumensis Mori)的分子遗传差异,为澄清其分类地位争议提供分子证据。结果表明:(1)扩增217个样本的mtDNA D-loop区序列,共获得45个单倍型,类群间无共享单倍型;基于单倍型构建的系统进化树显示三个细鳞鲑类群呈独立的支系;(2)基于14个呈多态性位点的遗传分化结果表明,秦岭细鳞鲑与尖吻或钝吻细鳞鲑之间的遗传距离均大于尖吻细鳞鲑和钝吻细鳞鲑之间的遗传距离;(3)基于线粒体D-loop和多态性微卫星位点计算出的遗传分化系数(F_ST)都远高于0.25表明三个类群间的遗传分化程度极高。这些结果表明,秦岭细鳞鲑与黑龙江流域细鳞鲑之间遗传分化程度高,结合前期发现秦岭细鳞鲑与黑龙江细鳞鲑类群有明显形态分化的研究结果及它们之间地理隔离已久的现状,研究初步判定秦岭细鳞鲑为独立物种,并建议以Brachymystax tsinlinge...     

Mitochondrial cytochrome b sequence variation in Korean salmonids

The complete 1141 bp mitochondrial cytochrome b sequences were determined for lenok Brachymystax lenok , cherry salmon Oncorhynchus masou masou , Ishikawa's cherry salmon O. m. ishikawai , chum salmon O. keta , rainbow trout O. mykiss , and an albino mutant of rainbow trout. Common substitutions detected in these species were transitional mutations. There were no significant differences in the intraspecific variation of the cytochrome b genes. Interspecific divergences were greater than intraspecific variation. The level of variation ranged from 8·026–15·686%. The cherry salmon was closer to chum salmon than to rainbow trout, and the lenok was the most distantly related species.     

温度和重复测定对秦岭细鳞鲑快速启动反应、游泳性能及力竭后代谢特征的影响

在全球气候变暖背景下,冷水性鱼类的温度适应性备受关注。秦岭细鳞鲑(Brachymystax lenok tsinlingensis)是目前世界上分布最南端的两种鲑科鱼类之一,为国家Ⅱ级重点保护水生野生动物。尽管温度是决定该物种生存与分布的关键因子,然而其热生物学相关研究至今鲜见报道。研究考察了驯化温度(6℃、12℃和18℃)和重复测定对秦岭细鳞鲑生态相关的重要指标如快速启动反应、游泳性能及力竭后代谢特征的影响。结果发现:(1)快速启动反应时滞(Latency time,Tlatency)随温度升高而变短(P<0.05),但温度和重复测定对反应率(Reaction rate,R)无显著影响(P>0.05);(2)温度对步法转换速度(Gait transition speed,Ugait)和匀加速游泳速度(Constant acceleration test speed,Ucat)影响显著(P<0.05),重复测定对Ugait和Ucat无显著影响(P>0.05);(3)温度对日常代谢率(Routine metabolic rate, RMR)和最大代谢率(Maximum metabolic rate, MMR)影响显著(P<0.05)、对代谢空间(Metabolic scope,MS)无显著影响(P>0.05),重复测定对MMR和MS均无显著影响(P>0.05);(4)低温驯化方向(6—12℃)生理参数的Q10值较大,而高温驯化方向(12—18℃)生理参数的Q10值较小。研究结果提示:(1)高温下秦岭细鳞鲑快速启动反应更为迅速,但该物种对低强度机械刺激主要采用静息而非逃逸的策略;(2)秦岭细鳞鲑游泳性能对温度变化的敏感性较高,游泳性能的最适温度估计介于12—18℃之间;(3)秦岭细鳞鲑具备较好的代谢恢复与重复运动能力,但总体上游泳性能较弱,可能易受生境水温和水流环境变化的限制。     

秦岭细鳞鲑代谢及低氧耐受能力对温度驯化的响应

为考察秦岭细鳞鲑（Brachymystax lenok tsinlingensis）代谢及低氧耐受能力对温度驯化的响应，将实验鱼于6℃、12℃和18℃下驯化4周后，采用密闭式呼吸代谢测定仪对其静止代谢率（Resting metabolic rate，RMR）和临界氧压（Critical oxygen press，P_crit）等参数进行测定。结果发现，RMR随驯化温度升高而升高，在6-12℃、12-18℃温度内，RMR的Q₁₀值分别为2.59和2.77，表明该物种对温度的敏感性较高；P_crit值随驯化温度升高而升高且与RMR显著正相关，在驯化温度范围内（6-18℃），P_crit提升了76.2%。研究结果提示:秦岭细鳞鲑应对低氧环境的生理可塑性较差，在高温下RMR增加可能是导致其低氧耐受能力降低的内在机制之一。     

Microsatellites from clade B Symbiodinium spp. specialized for Caribbean corals in the genus Madracis

In order to determine boundaries of genetic recombination among putative ‘species’ of endosymbiotic dinoflagellates, nine polymorphic microsatellite loci were developed and optimized for clade B Symbiodinium designated as type 7 (B7) and two related types, B13 and B13a. Together, they form a subclade in clade B that is specific to Caribbean corals in the genus Madracis. A total of 52 samples were analysed (including 43 B7, 2 B13, 7 B13a) originating from seven Caribbean locations. Diversity indices at each haploid locus ranged from 0.302 to 0.836 and four to 14 alleles were found per locus. The loci were preliminarily cross‐tested on closely related ‘ancestral’ B1 populations found in maze coral Meandrina meandrites and that of another host specialist, B5, from the lesser starlet coral Siderastrea radians.     

Evidence supporting the paraphyly of Hucho (Salmonidae) based on ribosomal DNA restriction maps

Relationships among the less derived genera in the subfamily Salmoninae were investigated by phylogenetic analysis of data from restriction maps of the ribosomal DNA using Osmerus mordax (rainbow smelt), Coregonus hoyi (bloater), and Thymattus arcticus (Arctic grayling) as outgroups. Analysis of the results suggests that Hucho h. taimen is more closely related to Brachymystax lenok (lenok) than to Hucho perryi (Sakhalin taimen) and that B. lenok and Hucho h. taimen (Eurasian taimen) form the most ancestral clade of the Salmoninae.     

基于线粒体DNA控制区序列变异探讨黑龙江和图们江细鳞鲑属鱼类的分类地位

基于细鳞鲑属Brachymystas鱼类的线粒体DNA控制区基因序列变异,对分布于黑龙江水系中国境内的尖吻细鳞鲑(sharp-snouted lenok)和钝吻细鳞鲑(blunt-snouted lenok),及分布于图们江的图们江细鳞鲑B.tumensis进行分子系统关系研究,为进一步确定黑龙江水系2种细鳞鲑的分类学地位、有效命名及图们江细鳞鲑物种地位性提供分子生物学依据.分布于黑龙江水系的细鳞鲑种群在系统发育树中明显构成2个独立的进化分支,分别对应可经形态鉴别而差异显著的尖吻细鳞鲑和钝吻细鳞鲑,平均序列分歧为1.9%,在属内已达到种间分化水平;图们江细鳞鲑与尖吻细鳞鲑的呼玛河、乌苏里江、奎勒河等种群共同构为1个进化分支,与尖吻细鳞鲑的序列分歧(平均为1.2%)远低于与钝吻细鳞鲑的序列分歧(平均为2.2%).结合形态学的初步研究结果(图们江细鳞鲑的主要形态特征偏向于尖吻细鳞鲑),不支持图们江细鳞鲑独立种的分类地位,建议为尖吻细鳞鲑B.lenok的同物异名,也不支持普遍认为的钝吻细鳞鲑的有效学名为B.tumensis,其有效命名还待商榷,暂属未定名种.综上所述,基于基因序列分析的遗传学结果进一步验证了形态学的分类结论,即在黑龙江水系细鳞鲑属有2个独立的种,分别为尖吻细鳞鲑B.lenok和钝吻细鳞鲑B.sp.,而图们江细鳞鲑B.tumensis应归为尖吻细鳞鲑B.lenok的同物异名.     

Isolation and characterization of microsatellite loci in Bemisia tabaci (Hemiptera: Aleyrodidae)

Microsatellite‐enriched genomic libraries were obtained from the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) using a magnetic/biotin capture of repetitive sequences. Ten dinucleotide markers were successfully isolated and characterized from these libraries. Variability was assessed in six populations of B. tabaci collected from different localities of the island of Crete, Greece. The number of alleles per locus in approximately 105 individuals screened across populations ranged from two to 13. Averaged observed heterozygosity over the six populations ranged from 0.001 to 0.58.