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1.
运用微卫星分子标记对80尾胭脂鱼人工放流子一代个体的遗传多样性和种群遗传结构进行了分析。用磁珠富集法构建了胭脂鱼(AAAG)n富集文库,从中分离并鉴定得到的22个微卫星位点最终设计合成18对引物。对长江中、上游的80尾人工增殖放流的胭脂鱼子一代进行了遗传多样性的初步研究,其中5对引物呈现多态性,等位基因数目为 2～8个;多态信息含量0.2957～0.8038;Shannon多样性指数0.5466～1.8840;观测杂合度0.3056～0.7222;期望杂合度0.3658～0.8381;Hard-Weinberg遗传偏离指数（D）-0.1818～0.4287。结果初步表明,胭脂鱼人工放流子一代处于较高的遗传多样性水平,但很大程度上仍受到人类活动的影响。 相似文献
2.
Population genetic structure of Atlantic salmon,Salmo salar L., in the River Tamar,southwest England
Abstract Population genetic studies can be useful for informing conservation and management. In Atlantic salmon, Salmo salar L., population structuring frequently occurs between river systems, but contrasting patterns occur within rivers, highlighting the need for catchment‐specific studies to inform management. Here, population structure of Atlantic salmon was examined in the River Tamar, United Kingdom, using 12 microsatellite loci. Gene diversity and allelic richness ranged from 0.80 to 0.84 and from 8.96 to 10.24, respectively. Some evidence of genetic structure was found, including significant genetic differentiation between samples in different subcatchments (pairwise θ and tests of genic differentiation), results from assignment tests and a pattern of isolation by distance. Conversely, structure revealed only one population cluster, and an analysis of molecular variance showed no significant variation between subcatchments. Evidence of population bottlenecks depended on the mutation model assumed and is discussed with reference to catchment‐specific studies of stock abundance. Implications for implementing management actions are considered. 相似文献
3.
Sren Mller Helmut M. Winkler Stefan Richter Ralf Bastrop 《Ecology of Freshwater Fish》2021,30(1):140-149
The Baltic Sea is a unique ecosystem and the largest body of brackish water in the world. It is inhabited by several originally freshwater fish species, one of them being pike (Esox lucius), which is adapted to the mesohaline conditions of the southern Baltic Sea and colonises its south‐western bays and lagoons. Using twelve microsatellite markers, we analysed the genetic structure of 407 Baltic Sea pike collected from ten locations in the coastal zone of the southern Baltic region and adjacent rivers and nearby lakes. We used traditional F‐statistics and a Bayesian approach implemented in STRUCTURE to investigate spatial structuring. Our results show an overall isolation by distance pattern with two distinct coastal clusters. The border area between the two clusters is characterised by a sharp salinity leap, indicating that the dispersal barrier is not physical, but physiological in nature. A third cluster was formed by three lake populations, presumably as a result of past stocking measures. Additional otolith microchemical studies demonstrate the brackish origin and residency of the majority of the pike from the coastal lagoons, supporting previous studies which suggest that the anadromous pike “ecotype” is scarce in this area of the Baltic Sea. Our results contribute to current knowledge on the population genetics of Baltic Sea pike in a previously unsampled area. 相似文献
4.
Maj Wetjen Thomas Schmidt Anne Schrimpf Ralf Schulz 《Fisheries Management and Ecology》2020,27(2):170-184
The genetic structure of the gadiform fish species, burbot Lota lota L., was investigated across Germany to derive management options for facilitating the preservation of genetic diversity. Sequence analysis of the mitochondrial control region (n = 244) and microsatellite analysis (n = 861) of specimens from 20 sites revealed genetic structuring between major river basins, and particularly between lake and river habitats. The admixture zone between the Eurasian and West European phylogenetic clades in Lake Constance was confirmed and expanded to include the drainage basins of the rivers Rhine and Schlei/Trave. Haplotype distribution and private haplotypes in single river basins indicated population differentiation and imply that German burbot constituted an important part of the entire species' diversity. The derived genetic structuring has implications for future stocking programmes and the preservation of the adaptive potential of burbot, a guiding species for oligotrophic lakes in Europe. 相似文献
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6.
- In the past, sturgeons played an important role in commercial and recreational fisheries in the Danube River and its tributaries. Human impacts in the Danube River Basin coupled with exploitation of sturgeon stocks led to all species being either locally extinct, critically endangered or of unknown status.
- Sterlet (Acipenser ruthenus, Linnaeus 1758) is the last known sturgeon species occurring in the upper and middle Danube; however, the population of this species is considered unbalanced and decreasing since the beginning of the twenty-first century.
- The decline of sturgeon stocks has been noted before owing to their economic importance. With commercial fisheries being forbidden in the Slovak section of the Danube River, there is generally no information available about the status of what is considered a local population.
- Databases containing recreational catch of sterlet (2003–2018) and historical records of commercial harvest (1961–1990) were used to describe the trend in the weight and number of sterlet caught over the following years.
- Modelling indicated that the number of fish caught each year appears to be lower, while the average weight of each individual is increasing. This might suggest that the population is ageing.
- Although older individuals can contribute a great deal more to spawning because they produce a greater number of eggs, several problems are apparent. The number of spawners might be decreasing as a result of bycatch or fishing, their ability to spawn might be obstructed, or annual recruitment may fail owing to unpredictable events.
- Although restocking programmes are in place to help maintain the sterlet population in the Danube River, their efficiency seems to be drastically low. In fact, restocking could be of little value unless studies on the availability of key habitats are conducted and their protection and restoration are ensured.
7.
微卫星DNA由于具有高度多态性、共显性遗传、基因组中含量丰富且随机分布等特点,目前已成为最有效的分子标记之一,并应用于种群分化研究、血缘分析、基因连锁分析、进化以及生态学研究等许多领域。近年来,海洋贝类微卫星的研究报道日益增多。本文对海洋贝类微卫星分离方法、开发现状、遗传学特性以及在种群遗传、家系分析、遗传多样性评价等方面的最新研究进展进行了综述,并分析了微卫星分析中无效等位基因、“结巴”带、短等位基因显性和等位基因“扩增丢失”现象的产生原因以及对微卫星基因型判读带来的影响。 相似文献
8.
Patrick W. DeHaan Jennifer Von Bargen Paul D. Scheerer 《Ecology of Freshwater Fish》2017,26(4):609-620
Many fish species exhibit diverse life history strategies that help maintain population viability. An understanding of the relationships among these strategies is crucial for prioritising conservation actions. The Warner sucker, endemic to the Warner Lakes Basin in southern Oregon, USA, is one example of a taxon where a lack of information regarding relationships among life history strategies has hampered conservation efforts. Warner suckers have two distinct life history types: stream‐type fish that have a fluvial life history and lake‐type fish that have an adfluvial life history. There are advantages and disadvantages associated with each life history, and presently the relationship between life history types is not well understood. Our objectives were to determine the amount of genetic variation within and among tributary populations of Warner suckers and to determine the origins of suckers collected in the Warner Lakes. We collected individuals from four tributary populations, a refugial population, and Hart and Crump lakes and genotyped them at 16 microsatellite loci. Estimates of genetic variation among populations suggested low levels of gene flow (FST = 0.153) and genetic variation among populations seemed to be influenced by population and habitat characteristics. Nearly all of the individuals collected in Hart and Crump lakes originated in a single tributary, Deep Creek, which likely reflects reduced habitat connectivity between most other tributaries and the Warner Lakes. Data presented in this study are useful for evaluating the status of Warner sucker populations and for prioritising conservation actions such as the removal and modification of barriers. 相似文献
9.
D. KNAPEN G. KNAEPKENS L. BERVOETS E. VERHEYEN & M. EENS 《Fisheries Management and Ecology》2009,16(2):112-120
Abstract Genetic variation within and among stone loach, Barbatula barbatula L., populations inhabiting anthropogenically degraded watercourses in Flanders (northern part of Belgium) was assessed using five microsatellite markers. High levels of genetic diversity were observed at all sampling sites, (MNA: 6.2–11.2; H O : 0.64–0.75; H E : 0.67–0.85). Estimates of the effective population size varied between 1535 and 3021 individuals and there were no indications of recent severe bottlenecks. Significant genetic differentiation was observed among sites belonging to different river systems and drainage basins. These results suggest human activities, such as pollution and river engineering, have not impacted significantly on genetic variability in the stone loach populations investigated. It is possible that this lack of genetic erosion may be attributed to species-specific characteristics such as pollution tolerance and ecological flexibility. 相似文献
10.
Elise M McKinna Satya Nandlal Peter B Mather David A Hurwood 《Aquaculture Research》2010,41(11):e730-e742
Four microsatellite markers and a mitochondrial DNA (mtDNA) fragment were used to investigate two possible explanations for a reported decline in productivity of genetically improved farmed tilapia (GIFT) in Fiji: (i) a decline in genetic diversity (GD) and (ii) genetic introgression from feral tilapia populations. Genetic diversity was estimated using θ and allelic richness, while Bayesian clustering was used to assign individuals to genetic groups (K=2 or 3) to test for introgression. Differentiation among groups was estimated using FST analysis. Results indicate that genetic diversity had declined compared with a GIFT reference stock from WorldFish Centre, while there was little evidence for introgression from feral tilapia populations. Loss of genetic diversity most probably resulted from practices that have not actively managed genetic resources in the hatchery. While GIFT is considered to be an improved line of Nile tilapia (Oreochromis niloticus), mtDNA analysis here revealed haplotypes assigned previously to three discrete Oreochromis species (O. niloticus, Oreochromis mossambicus and Oreochromis aureus) in both the Fijian strain and the WorldFish Centre strain. Possible sources for the three divergent lineages are discussed. Results have implications for the management and future expansion of the tilapia culture industry in Fiji as well as in other Pacific island nations. 相似文献
11.
This study was based on genotyping eight microsatellite loci of 463 brown trout, Salmo trutta L., sampled in nine differently sized tributaries in three areas on the eastern shore of Lake Mjøsa, south‐eastern Norway. The populations were genetically structured, and Mantel's test showed that genetic distance correlated positively with geographical distance. Temporal differentiation FST over a 2‐year period was estimated in five streams and was non‐significant after Bonferroni correction. Effective population size Ne was positively correlated with the habitat length available from the lake (0.3–22 km) and negatively with the number of full sib pairs in the sample. There was no correlation between Ne and genetic diversity, and private alleles were recorded in three medium‐sized streams, but not in the largest two. The importance of small spawning and nursery streams for the maintenance of genetic diversity of brown trout was demonstrated. 相似文献
12.
《水产资源保护:海洋与淡水生态系统》2018,28(2):370-382
- Ruppia species are distantly related to seagrasses and occur in saltwater coastal and inland lagoons, mostly as monospecific beds. The diversity of euryhaline Ruppia populations from different continents recently became better understood from a suite of chloroplast sequences but limited nuclear markers. These revealed a high complexity from hybridization, introgression, polyploidy and haplotypic divergence.
- Because of this complexity within the genus and multiple allelic states in polyploids, three multiplexed sets of 24 nuclear microsatellites were developed from four Ruppia provenances and cross‐amplified on 130 individuals from a wide range of taxa in various aquatic habitats on different continents.
- Secondly, pure R. cirrhosa and R. maritima individuals could be unambiguously identified from their introgressed hybrids and from other known or yet unidentified taxa, using diagnostic markers that referred to autotetraploid individuals in R. cirrhosa and allotetraploidy in an ancient hybrid complex ‘haplogroup E’.
- Thirdly, a phenetic barcoding approach of trnH‐psbA chloroplast haplotypes taking into account insertion–deletion variations, revealed lineages of recently described taxa from lagoons in different continents (i.e. R. sinensis, R. brevipedunculata, R. mexicana) in addition to separate lineages of hybrid origin. Congruence between pollination mode and diversification of lineages, allows one to hypothesize whether selfing underwater leads to clearly separated lineages whereas outcrossing at the water surface allows hybridization and extensive introgression with potential chloroplast capture.
- This study raises a renewed interest in cryptic lineages, hybrid taxa and shallow phylogenies of Ruppia lineages, thereby critically questioning worldwide distributions of least concern species. Recognition and monitoring of unique Ruppia lineages will support further studies on connectivity, survival strategies and movement ecology to aid in determining the conservation status of a wide variety of lagoon and coastal wetland habitats.
13.
Peter T. Euclide Natalie M. Flores Matthew J. Wargo C. William Kilpatrick J. Ellen Marsden 《Ecology of Freshwater Fish》2018,27(3):699-709
Most of what is known about sculpin population structure comes from research in streams; however, slimy sculpins are also a common benthic species in deep lakes. In streams, sculpins are considered to be a relatively inactive species, moving only small distances, and characteristically have high levels of genetic structure. We examined population genetic structure of slimy sculpin (Cottus cognatus) across multiple barriers and over distances up to 227 km in Lake Champlain (USA, Canada) and Lake Ontario (USA, Canada) to determine whether lake populations of sculpin are also highly structured. We predicted that slimy sculpin populations in Lake Champlain would be structured by six causeways as well as by distance, Lake Ontario populations would be structured only by distance, and differences between the lakes would be large relative to within‐lake differences. We examined microsatellite variation among 200 slimy sculpins from Lake Champlain and 48 slimy sculpins from Lake Ontario to evaluate patterns of population connectivity and structure. There was no indication of population substructuring within either lake but sculpin were genetically distinct between lakes. We conclude that there is a single, panmictic population of sculpin present in Lake Champlain and another potentially panmictic population in Lake Ontario, with no indication of genetic isolation by distance. Our results contrast with data from sculpin in streams, suggesting distance and habitat fragmentation exert little influence on population connectivity of benthic fish in lakes. 相似文献
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15.
Jussara Oliveira Vaini Rodrigo Rodrigues Domingues Bruno Lopes da Silva Ferrette Eric M. Hallerman Kenneth Gabriel Mota João Pedro Barreiros Alexandre Wagner Silva Hilsdorf 《水产资源保护:海洋与淡水生态系统》2021,31(8):2119-2130
- The dusky grouper Epinephelus marginatus is a large epinephelid species that occurs in the eastern and south-western Atlantic and western Indian Oceans. Late maturity, protogynous hermaphroditism, site fidelity, and overfishing have all contributed to its demographic decline.
- Connectivity and demography within a broad sampling of dusky grouper populations throughout its distribution were assessed. To do so, genetic variation at 11 polymorphic microsatellite loci and a partial sequence of the mitochondrial control region (mtCR) were evaluated.
- Two major mtCR lineages with a sequence divergence of 1.6% were found. The magnitude of genetic differentiation for mtCR among north and south Atlantic and Indian Ocean populations was high, with ΦST = 0.528.
- DEST and results of discriminant analysis of principal component revealed significant microsatellite genetic differentiation between all collection areas. Significant pairwise DEST showed moderate (0.084) to very great (0.603) differentiation. The effective population size was low for all localities, ranging between 25 (Azores Archipelago) and 311 (Rio Grande do Sul). The overall effective population size was estimated as 299 (confidence interval = 215–412), and there was no evidence of strong or recent bottleneck effects.
- Local and regional genetic structuring among dusky grouper populations is the consequence of the species' site fidelity, distribution across multiple oceanographic boundaries, and probably also of sequential hermaphroditism that contributes to the intensity of random genetic drift.
- The spatial pattern of genetic structuring of dusky groupers is such that fisheries management and conservation of population genetic integrity will have to be pursued at the local and regional scales.
16.
Terry D Beacham Shunpei Sato Shigehiko Urawa Khai D Le Michael Wetklo 《Fisheries Science》2008,74(5):983-994
Variation at 14 microsatellite loci was surveyed in 26 chum salmon Oncorhynchus keta populations from Japan, one population from West Kamchatka and three populations from North America to determine population
structure. Microsatellites were then applied to estimate stock composition of chum salmon in mixed-stock fisheries. The genetic
differentiation index (F
st) over all populations and loci was 0.031, with individual locus values ranging from 0.010 to 0.081. Seven regional populations
were observed in Japanese chum salmon, with late-run populations from the Pacific Coast of Honshu the most distinct. Japanese
populations displayed greater genetic diversity than did those in North America. Transplantation history in some Japanese
river populations influenced their present genetic characteristics. Analysis of simulated mixtures from fishery sampling suggested
that accurate and precise regional estimates of stock composition should be produced when the microsatellites were used to
estimate stock compositions. Stock compositions for a 2005 sample of maturing, migrating chum salmon off the north-west coast
of Hokkaido near the border of the Sea of Japan and the Sea of Okhotsk indicated that this region may be a migration corridor
for Hokkaido populations from the Sea of Japan coast. Microsatellites have the ability to provide fine-scale resolution of
stock composition in Japanese coastal fisheries. 相似文献
17.
ABSTRACT: The genetic diversity and population structure of Cyclina sinensis were assessed using amplified fragment length polymorphism (AFLP). Three hundred and fifty-four AFLP loci were analyzed in 160 individuals collected from Lvshun, Lianyungang, Yueqing and Dongxing of coastal China. High levels of genetic diversity were detected, where the percentage of polymorphic loci and average expected heterozygosity ranged 88.4–98.9% and 0.304–0.365, respectively. Analysis of molecular variance showed that variation among populations (24.4%) was highly significant ( P < 0.001). Accordingly, the global fixation index ( θ B ) averaged over loci was high (0.205). The large genetic differences among populations indicate restricted gene flow, congruent with limited dispersal capability of C. sinensis . The unweighted pair group method with arithmetic mean (UPGMA) tree topology constructed on the basis of Nei's genetic distances between populations showed a clear separation of the northern two populations from the southern two populations, suggesting that gene flow between the northern and southern regions is extremely low. This finding is additionally supported by the separate clustering of the four populations in the results of principal coordinate analysis. The useful information obtained in this study will offer insights to fine-tune conservation and fishery management measures in the future. 相似文献
18.
The persistence of the initial genetic structure despite later stocking with foreign conspecifics is influenced by several factors, leading to different levels of introgression. Stream spawning has been assumed to be the prevailing recruitment strategy of brown trout (Salmo trutta L.). However, in lakes with limited stream spawning habitat, but still with high natural recruitment, lake spawning has been proposed. Using fourteen microsatellites, we assessed the genetic structure in a small allopatric brown trout population in the Lake Skavatn, located on the Hardangervidda mountain plateau, Norway. A total of 265 brown trout were obtained from the lake itself, the outlet stream, two tributaries, a littoral sample from a presumed lake spawning site, a suggested stocking source, and a lake sample from 1967, representing the initial lake population. The six Skavatn samples were best represented by three genetic components, showing a shift from the initial population, but with no genetic signal from the suggested stocking source. The littoral sample had the largest similarity to the initial lake population, possibly indicating the importance of lake spawning in a system where streams offer unpredictable spawning and rearing conditions. Due to large annual variations in recruitment contributions from the different spawning and rearing locations, the genetic structure of the lake population probably vary over time. 相似文献
19.
The level of genetic diversity in a cultured Atlantic salmon (Salmo salar) population from Tasmania, Australia was examined at 11 microsatellite loci and compared with that in its progenitor population from the River Philip in Nova Scotia, Canada. The reference progenitor population consisted of archived scales collected from wild River Philip salmon in 1971 and 1972, not long after salmon from this river were imported into Australia in the mid‐1960s. The Tasmanian hatchery stock had a significant reduction in the mean number of alleles (31–43%) and mean allelic richness (28–39%) across all microsatellite loci compared with the wild Canadian population. Mean heterozygosity levels remained unchanged. Estimates of per‐generation effective population sizes for the Tasmanian population, based on allele frequency temporal variance with the wild progenitor population, ranged from 102–207 individuals and reflected hatchery records. 相似文献
20.
- The paleback darter, Etheostoma pallididorsum, is considered imperilled and has recently been petitioned for listing under the Endangered Species Act. Previous allozyme-based studies found evidence of a small effective population size, warranting conservation concern. The objective of this study was to assess the population dynamics and the phylogeographical history of the paleback darter, using a multilocus microsatellite approach and mitochondrial DNA.
- The predictions of this study were that: paleback darter populations will exhibit low genetic diversity and minimal gene flow; population structure will correspond to the river systems from which the samples are derived; reservoir dams impounding the reaches between the Caddo and Ouachita rivers would serve as effective barriers to gene flow; and the Caddo and Ouachita rivers are reciprocally monophyletic.
- Microsatellite DNA loci revealed significant structure among sampled localities (global Fst = 0.17, P < 0.001), with evidence of two distinct populations representing the Caddo and Ouachita rivers. However, Bayesian phylogeographical analyses resulted in three distinct clades: Caddo River, Ouachita River, and Mazarn Creek. Divergence from the most recent ancestor shared among the river drainages was estimated at 60 Kya. Population genetic diversity was relatively low (He = 0.65; mean alleles per locus, A = 6.26), but was comparable with the population genetic diversity found in the close relatives slackwater darter, Etheostoma boschungi (He = 0.65; A = 6.74), and Tuscumbia darter, Etheostoma tuscumbia (He = 0.57; A = 5.53).
- These results have conservation implications for paleback darter populations and can be informative for other headwater specialist species. Like other headwater species with population structuring and relatively low genetic diversity, the persistence of paleback darter populations is likely to be tied to the persistence and connectivity of local breeding and non-breeding habitat. These results do not raise conservation concern for a population decline; however, the restricted distribution and endemic status of the species still renders paleback darter populations vulnerable to extirpation or extinction.