Parallel evolution of ecomorphological traits in the European whitefish Coregonus lavaretus (L.) species complex during postglacial times

The extensive phenotypic polymorphism in the European whitefish has triggered evolutionary research in order to disentangle mechanisms underlying diversification. To illuminate the ecological distinctiveness in polymorphic whitefish, and evaluate taxonomic designations, we studied nine Norwegian lakes in three watercourses, which each harboured pairs of divergent whitefish morphs. We compared the morphology and life history of these morphs, documented the extent of genetic differentiation between them, and contrasted the niche use of sympatric morphs along both the habitat and resource axes. In all cases, sympatric morphs differed in the number of gill rakers, a highly heritable trait related to trophic utilization. Individual growth rate, age and size at maturity, diet and habitat use also differed between morphs within lakes, but were remarkably similar across lakes within the same morph. Microsatellite analyses confirmed for all but one pair that sympatric morphs were significantly genetically different, and that similar morphs from different lakes likely have a polyphyletic origin. These results are most compatible with the process of parallel evolution through recurrent postglacial divergence into pelagic and benthic niches in each of these lakes. We propose that sparsely and densely rakered whitefish sympatric pairs may be a likely case of ecological speciation, mediated in oligotrophic lakes with few trophic competitors.     

Molecular phylogeny of the subfamily Schizothoracinae (Teleostei: Cypriniformes: Cyprinidae) inferred from complete mitochondrial genomes

The schizothoracine fishes, members of the Teleost order Cypriniformes, are one of the most diverse group of cyprinids in the Qinghai–Tibetan Plateau and surrounding regions. However, taxonomy and phylogeny of these species remain unclear. In this study, we determined the complete mitochondrial genome of Schizopygopsis malacanthus. We also used the newly obtained sequence, together with 31 published schizothoracine mitochondrial genomes that represent eight schizothoracine genera and six outgroup taxa to reconstruct the phylogenetic relationships of the subfamily Schizothoracinae by different partitioned maximum likelihood and partitioned Bayesian inference at nucleotide and amino acid levels. The schizothoracine fishes sampled form a strongly supported monophyletic group that is the sister taxon to Barbus barbus. A sister group relationship between the primitive schizothoracine group and the specialized schizothoracine group + the highly specialized schizothoracine group was supported. Moreover, members of the specialized schizothoracine group and the genera Schizothorax, Schizopygopsis, and Gymnocypris were found to be paraphyletic.     

Empirical evaluation of phenotype–environment correlation and trait utility with allopatric and sympatric whitefish, Coregonus lavaretus (L.), populations in subarctic lakes

Adaptive phenotypic divergence of sympatric morphs in a single species may have significant evolutionary consequences. In the present study, phenotypic impacts of predator on zooplankton prey populations were compared in two northern Finnish lakes; one with an allopatric whitefish, Coregonus lavaretus (L.), population and the other with three sympatric whitefish populations. First, we examined whether there were phenotypic associations with specific niches in allopatric and sympatric whitefish. Second, trait utility (i.e. number of gillrakers) of allopatric and sympatric whitefish in utilizing a pelagic resource was explored by comparing predator avoidance of prey, prey size in environment, and prey size in predator diet. The allopatric living large sparsely rakered (LSR) whitefish morph, was a generalist using both pelagic and benthic niches. In contrast, sympatric living whitefish morphs were specialized: LSR whitefish was a littoral benthivore, small sparsely rakered whitefish was a profundal benthivore and densely rakered (DR) whitefish was a pelagic planktivore. In the lake with allopatric whitefish, zooplankton prey did not migrate vertically to avoid predation whereas, in the lake with sympatric whitefish, all important prey taxa migrated significantly. Trait utility was observed as significantly smaller size of prey in environment and predator diet in the lake with DR whitefish than in the lake with only LSR whitefish.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 92 , 561–572.     

Phylogeography of the endemic Gymnocypris chilianensis (Cyprinidae): sequential westward colonization followed by allopatric evolution in response to cyclical Pleistocene glaciations on the Tibetan Plateau

The schizothoracine Gymnocypris chilianensis is restricted to the Shiyang, Ruoshui and Shule Rivers, listed from east to west, along the northeast edge of the Tibetan Plateau. This distribution provides a valuable system to test hypotheses about postglacial colonization. We used mitochondrial DNA sequence data (a control region and the cytochrome b gene; 1894 bp) to assess the phylogeographic structure of this species based on 278 specimens sampled from throughout the species' entire geographical range. We found three lineages corresponding geographically to the three rivers, suggesting three independent glacial differentiation centers within the northeast edge of the Tibetan Plateau. The phylogenetic analysis suggested that the Shiyang River population forms a lineage that separated from the other populations of G. chilianensis at the basal phylogenetic split within this species. The molecular data further demonstrated a clear pattern of decreasing genetic diversity from the eastern Shiyang River towards the central Ruoshui River and western Shule River lineages, a pattern consistent with sequential western colonization. We therefore propose a phylogeographic scenario for G. chilianensis of a gradual westerly expansion from the Shiyang River population along the northeast edge of the Tibetan Plateau, with subsequent allopatric evolution at approximately 0.37 and 0.05 million years ago (Ma), through at least two glacial maxima. Together with the genetic evidence reported in other species, our findings suggest that this common biogeographic pattern emphasizes the importance of the northeastern edge region of the Tibetan Plateau as a hotspot of genetic diversity for some taxa.     

南门峡裂腹鱼亚科鱼类形态相似种的分类学地位——形态趋同进化实例

受高原抬升所致的水系变迁及人类活动的影响,分布于南门峡河流的裂腹鱼亚科鱼类与黄河干支流种群间的基因交流受到长期限制。作为孤立小群体,探讨其分类学地位及其在小生境中的进化机制对了解青藏高原鱼类多样性和物种的形成、进化具有重要意义。本文采用聚合酶链式反应(PCR)和直接测序方法获得了南门峡裂腹鱼亚科鱼类(n=29)及其近缘种(n=19)共48个个体的线粒体DNA(mtDNA)细胞色素b(cytb)基因的全序列(1140bp),并以厚唇裸重鱼和尖裸鲤为外群构建了MP和Bayesian系统进化树。南门峡裂腹鱼亚科鱼类29个个体的序列经排序后,发现有100个(8·77%)多态性位点,共定义了16个单倍型,在系统进化树上分布于截然不同的两个族群中。其中5个单倍型(NMX3、6、7、13、15)与其近缘种花斑裸鲤和青海湖裸鲤形成单系群(MP99%,Bayesian98%),而其余11个单倍型(NMX1、2、4、5、8、9、10、11、12、14、16)与黄河干支流的黄河裸裂尻鱼形成另一个单系群(MP99%,Bayesian99%)。序列差异分析显示,分布于不同族群的南门峡裂腹鱼亚科鱼类之间存在较大的碱基差异(平均为7·42%),显示出种间差异水平,表明分布于南门峡河流的裂腹鱼亚科鱼类可能是花斑裸鲤和黄河裸裂尻鱼形态相似种的复合体。结合青藏高原隆升所致的气候环境变化和高原北部水系变迁的事件,推断形态趋同进化可能导致了南门峡河流裂腹鱼亚科鱼类形态相似种的共存,而小生境自然选择压力是引发适应性形态趋同进化的主要原因。     

青海可鲁克湖水鸟季节动态及渔鸥活动区分析

2008-2010年,对青海可鲁克湖的水鸟季节动态进行了调查。共记录到54种34828只水鸟,隶属于6目11科,雁鸭类水鸟最多,共统计到28445只,占水鸟总数的81.7%;其次是鸥类和鸻鹬类。可鲁克湖在水鸟春秋季迁徙高峰期在4月和10月,这也是水鸟多样性较高的两个月,其主要原因是由于迁徙鸭类数量和种类的增加。卫星跟踪表明,可鲁克湖是青海湖繁殖渔鸥重要的停歇地,渔鸥在可鲁克湖的停歇天数每年也有所不同,2007年和2008年秋季较2006年停歇时间短一些,初步判断与当地的人为干扰有关。当地政府对道路进行修建,其正好位于渔鸥的活动区内,这对渔鸥的日常活动造成较大影响,迫使渔鸥提前离开可鲁克湖。春季停歇天数的不同主要与青海湖面冰融的时间有关,若青海湖由于温度较高,冰融的时间早一些,渔鸥可能提前离开可鲁克湖,前往青海湖进行繁殖活动。     

Linear growth of sparsely rakered whitefish <Emphasis Type="Italic">Coregonus lavaretus</Emphasis> (Coregonidae) of the Imandra Lake (Murmansk oblast)

This paper studies the properties of linear growth in sparsely rakered whitefish Coregonus lavaretus in the stretches of the large subarctic Imandra Lake, which are characterized by the diversity of habitat conditions and anthropogenic stress levels. The groups of sparsely rakered whitefish that are confined to different areas of the lake are marked out based on the properties of growth, trophic status, and anthropogenic stress intensity. A direct relationship of the linear growth in whitefish with the age of sexual development and trophic level of its habitats is found.     

Ecophenotypic plasticity leads to extraordinary gastropod shells found on the “Roof of the World”

The often extraordinary shell forms and shapes of gastropods found in palaeolakes, such as the highly diverse Gyraulus fauna of the famous Steinheim Basin, have been puzzling evolutionary biologists for centuries, and there is an ongoing debate whether these aberrant shell forms are indicative of true species (or subspecies) or ecophenotypic morphs. Interestingly, one of the Steinheim Gyraulus morphs – a corkscrew-like open-coiled shell – has a recent analogue in the Lake Bangong drainage system on the western Tibetan Plateau. Therefore, a combination of morphological, molecular, palaeolimnological, and ecological analyses was used in this study to assess whether the extraordinary shell shape in Gyraulus sp. from this drainage system represents a (young) ecophenotypic phenomenon or if it has been genetically fixed over an extended period of time. Our morphological, ecological, and palaeolimnological data suggest that the corkscrew-like specimens remain restricted to a small pond near Lake Bangong with an elevated pH value and that the colonization may have occurred recently. The phylogenetic reconstruction based on two gene fragments shows that these nonplanispiral specimens cluster within the previous described Tibetan Plateau Gyraulus clade N2. A network analysis indicates that some haplotypes are even shared by planispiral and nonplanispiral specimens. Given the ephemerality of the phenomenon, the compact network patterns inferred, the likely young phylogenetic age of the aberrant Gyraulus shells studied, and the ecological peculiarities of the study site, we suggest that the evolution of the aberrant shell forms on the Tibetan Plateau could likely be considered as a rapid ecophenotypic response, possibly induced by ecological stress. This finding may thus have implications for the ongoing debate about the processes that have caused the extraordinary shell diversity in palaeolakes such as the Steinheim Basin.     

The biogeography and phylogeny of schizothoracine fishes (Schizopygopsis) in the Qinghai‐Tibetan Plateau

Freshwater fish belonging to the genus Schizopygopsis are widespread in drainages throughout the Qinghai‐Tibetan Plateau and, thus, a model group with which to investigate how paleo‐drainage changes linked to historical uplifting within the Qinghai‐Tibetan Plateau influence speciation. To date, the phylogenetic and taxonomic relationships within Schizopygopsis remain controversial. In this study, we constructed a comprehensive molecular phylogeny of Schizopygopsis based on six mitochondrial gene sequences. We compared the taxonomic relationships revealed by this phylogeny with those obtained from morphological data. We also used this phylogeny to assess the extent to which the evolution of Schizopygopsis has been driven by paleo‐drainage changes linked to uplifting of the Qinghai‐Tibetan Plateau. Results indicated that all Schizopygopsis taxa formed a monophyletic group comprising five major clades, which were inconsistent with the taxonomic relationships based on morphology for this group. Our results also strongly supported the validity of S. anteroventris and S. microcephalus as distinct species within Schizopygopsis. Molecular calibrations showed that species within the middle Yangtze species diverged earlier (~4.5 Mya) than species within the Indus River (~3.0 Mya), the Mekong River (~2.8 Mya) and the Tsangpo + Salween rivers (~2.5 Mya). The most recent evolutionary splits occurred among species from the upper and lower Yangtze River, the Yellow River and the Qiadam Basin at about 1.8 to 0.3 Mya. Our molecular evidence and use of the molecular clock calibration have allowed us to associate speciation events within the genus Schizopygopsis to the formation and separation of paleo‐drainage connections caused by tectonic events during the uplifting of the Qinghai‐Tibetan Plateau (~4.5 Mya). This work underlines the dominant role of vicariance in shaping the evolutionary history of the genus Schizopygopsis. Further research using multiple loci and more extensive sampling will reveal a more complete picture of the phylogenetic relationships and biogeography of Schizopygopsis fishes.     

Seasonal movements and habitat use of river whitefish (Coregonus lavaretus) in the Koitajoki River (Finland), as determined by Carlin tagging and acoustic telemetry

In the Koitajoki River, Eastern Finland, there exists a self-sustaining population of river-spawning densely rakered whitefish (Coregonus lavaretus pallasi). The population has been classified as near-threatened due to overexploitation and possible hybridization with the lake-spawning sparsely rakered whitefish form. Thus, knowledge of habitat use, movements, and migrations is important for threat assessment and management decisions. We employed conventional tagging and acoustic telemetry to provide information on movements and home range of the Koitajoki River whitefish. We tagged mature individuals at their spawning areas and followed fish movements by tag recoveries and continuously recording fixed receiving stations. The maximum movement distances were 40–50?km both upstream and downstream from the releasing site. There were indications of a clear seasonal migration pattern and spawning-site fidelity; riverine habitats were mainly occupied for spawning and overwintering, while feeding and growth mainly took place in lacustrine environments within several lakes of the river system. Due to their migratory nature, whitefish is vulnerable to environmental disturbances and overfishing in a large geographic area.     

Responses of plants to changes in Qinghai–Tibetan Plateau and glaciations: Evidence from phylogeography of a Sibiraea (Rosaceae) complex

The genetic structure and phylogeographical history of the alpine shrubs Sibiraea angustata (Rosaceae) and Sibiraea laevigata from the Qinghai–Tibetan Plateau (QTP) were investigated to identify alpine plant responses to changes in the QTP and glaciations. Fifty-five populations were analyzed using four chloroplast DNA (cpDNA) regions and (nuclear ribosomal internal transcribed spacer) nrITS sequence data. In all, 21 cpDNA haplotypes and 13 nrITS sequence types were detected. Analyses of the genetic diversity and phylogenetic relationships detected two rarely reported glacial refugia. One was the Yushu–Nangqian area, and the other consisted of the area from the Songpan Plateau to the southeastern margin of the QTP. Sibiraea species populations experienced divergent evolution and founder effects when they recolonized the QTP platform and adjacent high-altitude regions following glaciations. The divergence times of the main lineages and haplotypes were in the range of 1.60–2.58 Ma. The population size of Sibiraea species in the QTP decreased approximately 23-fold during the last 0.12 Ma, indicating that Sibiraea species were significantly affected by environmental changes in the QTP. Therefore, the rapid uplift of the QTP and subsequent glaciations likely played an important role in driving genetic divergence and population size changes of Sibiraea species in the QTP.     

Phylogeography of freshwater fishes of the Qilian Mountains area (<Emphasis Type="Italic">Triplophysa leptosoma</Emphasis>, Cobitidae: Cypriniformes)

The effects of the physical environment on populations of organisms endemic to the Tibetan Plateau and its surrounding areas have attracted increased scientific interest in recent years. Triplophysa leptosoma (Cobitidae: Cypriniformes) is an endemic species restricted to the Tibet Plateau and adjacent areas. Its distribution includes river systems around the Qilian mountains areas which located in the northeast edge of Tibet Plateau, including the Shiyang River, Heihe River and Shule River in the Hexi Corridor, Qaidam Basin river system and Yellow River system. In this study, we use mitochondrial DNA sequences (cytochrome b gene 1000 bp and cytochrome oxidase I gene 635 bp) to investigate the effects of geomorphological changes associated with the uplift of the Qilian Mountains on the major patterns of intraspecific diversification and population structure of the T. leptosoma. Based on our data, phylogenetic relationships among the 48 haplotypes revealed five major clades with strong geographic orientation. Our results suggest that the origin of these clades may correspond to the intermittent uprise of the Qilian Mountains. The Quaternary climatic changes and glacial-interglacial cycles had an important effect on the differentiation of haplotypes and the genetic diversity of the T. leptosoma. Meanwhile, population expansion also occurred during the repeated glacial event and the basin interconnections in the past.     

High altitude adaptation of the schizothoracine fishes (Cyprinidae) revealed by the mitochondrial genome analyses

The schizothoracine fishes, also known as “mountain carps” are widely distributed in the Qinghai-Tibetan Plateau and its peripheral regions. Although they provide a prime example of high altitude adaptation, the phylogenetic relationships and the divergence times among these carp lineages are still controversial. Moreover, the genetic basis for high altitude adaptation is also poorly understood. In this study, we determined the mitochondrial genomes from two species of the schizothoracine fishes, representing a “morphologically primitive” clade and “morphologically specialized” clade, respectively. The phylogenetic tree and the divergence times were estimated within the evolutionary framework of the entire order Cypriniformes. Our results indicate a polyphylyetic relationship of the schizothoracine fishes and suggest two independent migration events into the Qinghai-Tibetan Plateau: one by the “morphologically primitive” clade in the Late Miocene and another by the “morphologically specialized” clade in the Eocene. Rapid speciation events of each clade from the Late Miocene to the Pliocene correspond to the timing of the geologic acceleration of the Qinghai-Tibetan Plateau. Interestingly, we found evidence for positive selection acting on the protein coding genes in the mitochondrial genomes of the “morphologically specialized” clade, implying a possible genetic basis for high altitude adaptation in this derived lineage of cypriniform fishes.     

Phylogeography and conservation genetics of Lake Qinghai scaleless carp Gymnocypris przewalskii

The objective of this study was to examine the spatial genetic relationships of the Lake Qinghai scaleless carp Gymnocypris przewalskii within the Lake Qinghai system, determining whether genetic evidence supports the current taxonomy of Gymnocypris przewalskii przewalskii and Gymnocypris przewalskii ganzihonensis and whether Gymnocypris przewalskii przewalskii are returning to their natal rivers to spawn. Comparison of mitochondrial (control region) variation (42 haplotypes in 203 fish) of G. przewalskii with the postulated ancestral species found in the Yellow River, Gymnocypris eckloni (10 haplotypes in 23 fish), indicated no haplotype sharing, but incomplete lineage sorting. Consistent with the sub-species status, an AMOVA indicated that the Ganzi River population was significantly different from all other river populations (F(ST) = 0·1671, P < 0·001). No genetic structure was found among the other rivers in the Lake Qinghai catchment. An AMOVA of amplified fragment length polymorphism (AFLP) loci, however, revealed significant genetic differences between most spawning populations (F(ST) = 0·0721, P < 0·001). Both mitochondrial and AFLP data found significant differences among G. p. przewalskii, G. p. ganzihonensis and G. eckloni (F(ST) values of 0·1959 and 0·1431, respectively, P < 0·001). Consistent with the incomplete lineage sorting, Structure analysis of AFLP loci showed evidence of five clusters. One cluster is shared among all sample locations, one is unique to G. p. ganzihonensis and G. eckloni, and the others are mostly found in G. p. przewalskii. Genetic evidence therefore supports the current taxonomy, including the sub-species status of G. p. ganzihonensis, and is consistent with natal homing of most Lake Qinghai populations. These findings have significant implications for the conservation and management of this unique and threatened species. The evidence suggests that G. p. przewalskii should be treated as a single population for conservation purposes. Exchangeability of the populations, however, should not be used to promote homogenization of fish spawning in the different rivers. As some degree of genetic divergence was detected in this study, it is recommended that the spawning groups be treated as separate management units.     

黄河裸裂尻鱼群体遗传结构和Cyt b序列变异

测定了来自黄河上游和柴达木盆地托索湖的裸裂尻鱼共16个个体的Cytb基因全序列(1141bp),探讨了种群结构和遗传多样性。用MEGA2.1软件分析了碱基组成和序列变异;以青海湖裸鲤、花斑裸鲤和极边扁咽齿鱼为外类群,用PAUP*4.0b10程序构建了单倍型NJ树;用Arlequin Ver.2000程序计算了群体间遗传变异值(Fst)和Nm值以及群体分化概率值。结果显示,来自柴达木水系托索湖的裸裂尻鱼没有形成单系群,Fst=0.204(P0.05),Nm=1.95。初步判断,黄河和柴达木水系托索湖的裸裂尻鱼未显著分化,支持将柴达木裸裂尻鱼(Schizopygopsis kessleri)归并入黄河裸裂尻鱼(Schizopygopsis pylzovi)的形态学结果。两种群核苷酸多样度()分别为0.0012和0.0026,表现为较低水平。根据校正的分子钟推测,黄河和托索湖裸裂尻鱼群体分歧时间为距今7万年左右的更新世末期,结合地理分布的资料和古地质事件,对黄河裸裂尻鱼群体分布水系间的历史联系进行了分析。       

Genetic diversity and historical population structure of Schizopygopsis pylzovi (Teleostei: Cyprinidae) in the Qinghai–Tibetan Plateau

1. Complete sequences of 1140 base pair of the cytochrome b gene from 133 specimens were obtained from nine localities including the inflow drainage system, isolated lakes and outflow drainage system in Qinghai–Tibetan Plateau to assess genetic diversity and to infer population histories of the freshwater fish Schizopygopsis pylzovi. 2. Nucleotide diversities (π) were moderate (0.0024–0.0045) in populations from the outflow drainage system and Tuosuo Lake, but low (0.0018–0.0021) in populations from Qiadam Basin. It is probable that the low intra‐population variability is related with the paleoenvironmental fluctuation in Qiadam Basin, suggesting that the populations from Qiadam Basin have experienced severe bottleneck events in history. 3. Phylogenetic tree topologies indicate that the individuals from different populations did not form reciprocal monophyly, but the populations from the adjacent drainages cluster geographically. Most population pairwise F_ST tests were significant, with non‐significant pairwise tests between Tuosu Lake and Tuosuo Lake in the north‐west of the Qinghai–Tibetan Plateau. Analysis of molecular variance (amova ) indicates that the significant genetic variation was explained at the levels of catchments within and among, not among specific boundaries or inflow and outflow drainage systems. 4. The nested clade phylogeographical analysis indicates that historical processes are very important in the observed geographical structuring of S. pylzovi, and the contemporary population structure and differentiation of S. pylzovi may be consistent with the historical tectonic events occurred in the course of uplifts of the Qinghai–Tibetan Plateau. Fluctuations of the ecogeographical environment and major hydrographic formation might have promoted contiguous range expansion of freshwater fish populations, whereas the geological barriers among drainages have resulted in the fragmentation of population and restricted the gene flow among populations. 5. The significantly large negative F_s‐value (−24.91, P < 0.01) of Fu's F_s‐test and the unimodal mismatch distribution indicate that the species S. pylzovi underwent a sudden population expansion after the historical tectonic event of the Gonghe Movement. 6. The results of this study indicate that each population from the Qinghai–Tibetan Plateau should be managed and conserved separately and that efforts should be directed towards preserving the genetic integrity of each group.     

玛曲高寒草甸湿地植物构成及其集合种群群落的多样性维持机理

高寒草甸及湿地是青藏高原上最为重要的生态系统,它的状况直接关系到我国江河源头的蓄水量.也关系到我国中部和东部广大地区的工农业及人民生活用水．因此对青藏高原高寒草甸与湿地的保护具有重要的现实意义。本研究对青藏高原东北缘黄河源头地区甘南藏族自治州的玛曲县高寒草甸及湿地进行调查,揭示了该地区的植被生物多样性情况与组成结构,利用解析层次方法分析了高寒草甸及湿地的退化原因及恢复手段,同时还从集合种群竞争原理出发对该地区植被生物多样性的维持机理进行了讨论。结果显示出两个现存的主要矛盾：在生物多样性保护与高寒草甸质量提高方面存在矛盾;在地区发展与高寒草甸质量提高方面也存在矛盾。前者表明为了提高物种多样性,必须存在一定干扰．包括人为干扰与自然生态系统干扰,这些干扰会在高寒草甸中形成一定数量的空斑块．这些空斑块为先锋种的繁殖提供了暂时的场所从而使多样性得到提高与维持。但由于先锋种普遍为杂草类而非优良牧草．因此这种多样性维持只能以牺牲草甸质量为代价。第二个矛盾说明为了提高当地经济与社会发展．必然会增加人为干扰,而这些干扰会首先对优良牧草造成不利,从而使杂草比例增加并进一步抑制牧场质量从而限制地区以畜牧业为主的经济发展。     

Correlation analysis between genetic and chemical differences of Nardostachys jatamansi from different habitats in Ganzi Tibetan Autonomous Prefecture,Sichuan Province,China

In the traditional Tibetan medicinal system, the medicinal parts of Nardostachys jatamansi (D.Don) DC. include the dried roots and rhizomes, which is effective in treating various diseases. In this study, molecular evolutionary analysis based on three markers (i.e., ITS, matK and rbcL), and principal component analysis (PCA) combined with ¹H NMR measurements were used to assess the genetic and chemical differences of the N. jatamansi from different habitats in Ganzi Tibetan Autonomous Prefecture, Sichuan Province, China. The results showed that the ITS marker was highly effective to identify the intraspecific variation of N. jatamansi. Furthermore, the results of the chemical analysis indicated that the nardosinone and sucrose, as the metabolite landmarks, can distinguish the different habitats of N. jatamansi in Ganzi Tibetan Autonomous Prefecture, Sichuan Province, China. Moreover, combining the chemical analysis with phylogenetic analysis, the results indicated that the metabolites differences may be affected not only by genetic structures but also by environmental factors. These findings provide valuable references for the effective protection and exploitation of N. jatamansi resources.     

The youngest split in sympatric schizothoracine fish (Cyprinidae) is shaped by ecological adaptations in a Tibetan Plateau glacier lake

Although new empirical evidence shows that sympatric speciation has occurred in some species, there are few indisputable model organisms for this process of speciation. The two subspecies ( Gymnocypris eckloni eckloni and G . e . scoliostomus ) of the schizothoracine Gymnocypris fish species complex from a small glacier lake in the Tibetan Plateau, Lake Sunmcuo, fit several of the key characteristics of the sympatric speciation model. We used combined mitochondrial control region sequences and the cytochrome b gene (1894 bp) to address the phylogenetics and population genetics of 232 specimens of G . e . eckloni and G . e . scoliostomus , as well as all of its closely related sister species. We found that: (i) a total of four old lineages were uncovered in the widespread G . e . eckloni , of which only one was shown to be shared with all G . e . scoliostomus individuals and (ii) the new subspecies ( G . e . scoliostomus ) evolved in Lake Sunmcuo from the ancestral G . e . eckloni population within approximately 0.057 Ma. These two taxa of the species complex are morphologically distinct, and reproductive isolation is further suggested. Ecological disruptive selection based on morphological traits (e.g. mouth cleft characters) and food utilization may be a mechanism of incipient speciation of two sympatric populations within Lake Sunmcuo. This study provides the first genetic evidence for sympatric speciation in the schizothoracine fish.     

青藏高原纳木错水生植物多样性及群落生态学研究

野外采集和文献记载结果显示纳木错共有水生植物34种(变种),隶属于15科19属。其中,轮藻门植物1科1属1种、单子叶植物7科8属16种、双子叶植物7科10属17种。纳木错区水生植物区系整体上表现出鲜明的北温带性质。种联结分析表明纳木错水生植物种间相关性显著,这些种组构成一个连续体。样地调查显示,纳木错主要水生植物群落有11种,以沉水植物群落类型为主,兼有少量的浮叶植物群落。β-多样性测度表明,样地间种类组成随水环境差异变化明显。