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1.
In this study, the localization of fluorescent protein (FP) was characterized in the muscles of four species and two subspecies of eels Anguilla anguilla, A. australis, A. bicolor bicolor (b.), A. bicolor pacifica (p.) and A. mossambica in addition to the previously reported A. japonica. The open reading frame of each eel FP was 417 bp encoding 139 amino acid residues. The deduced amino acid sequences among the four species and two subspecies exhibited 91.4–100% identity, and belonged to the fatty-acid-binding protein (FABP) family. The gene structure of eel FPs in A. japonica, A. anguilla, A. australis, A. bicolor b., A. bicolor p. and A. mossambica have four exons and three introns, and were common to that of FABP family. The apo eel FPs expressed by Escherichia coli with recombinant eel FP genes were analysed for the fluorescent properties in the presence of bilirubin. The excitation and emission spectra of holo eel FPs had the maximum wavelengths of 490–496 and 527–530 nm, respectively. The holo eel FPs indicated that the fluorescent intensities were stronger in A. japonica and A. bicolor than in A. mossambica, A. australis and A. anguilla. The comparison of amino acid sequences revealed two common substitutions in A. mossambica, A. australis and A. anguilla with weak fluorescent intensity.  相似文献   

2.

Background

Since its introduction from Taiwan to Europe around 1980, Anguillicola crassus, a natural parasite of the Japanese eel (Anguilla japonica), has acquired the European eel (Anguilla anguilla) as a novel definitive host. In this host the nematode differs noticeably in its body mass and reproductive capacity from its Asian conspecifics. We conducted a common garden experiment under a reciprocal transplant design to investigate whether differences in species-diagnostic morphological traits exist between two European and one Asian population of A. crassus and if yes whether these have a genetically fixed component.

Results

We found that worms from Germany, Poland and Taiwan differ in the size and shape of their body, oesophagus and buccal capsule. These changes are induced by both phenotypic plasticity and genetic divergence: in the European eel, nematodes from Europe as well as from Taiwan responded plastically with larger body and oesophagus dimensions compared to infections in the Japanese eel. Interestingly, the oesophagus simultaneously shows a high degree of genetically based changes being largest in the Polish strain kept in A. anguilla. In addition, the size and shape of the buccal capsule has undergone a rapid evolutionary change. Polish nematodes evolved a genetically fixed larger buccal capsule than the German and Taiwanese populations. The German strain had the smallest buccal capsule.

Conclusions

This study provides evidence for the genetic divergence of morphological traits in A. crassus which evolved over a timescale of about 30 years. Within Europe and in the European eel host these alternations affect characters used as diagnostic markers for species differentiation. Thus we provide an explanation of the discrepancy between morphological and molecular features reported for the parasitic nematode featured here, demanding general caution in morphological diagnosis of parasites discovered in new hosts.
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3.
The article presents the genetic parameters of the populations of lizards of the Darevskia raddei complex (D. raddei nairensis and D. raddei raddei) and the populations of D. valentini calculated on the basis of the analysis of variability of 50 allelic variants of the three nuclear genome microsatellite-containing loci of 83 individuals. It was demonstrated that the Fst genetic distances between the populations of D. raddei nairensis and D. raddei raddei were not statistically significantly different from the Fst genetic distances between the populations of different species, D. raddei and D. valentini. At the same time, these distances were statistically significantly higher than the Fst distances between the populations belonging to one species within the genus Darevskia. These data suggest deep divergence between the populations of D. raddei raddei and D. raddei nairensis of the D. raddei complex and there arises the question on considering them as separate species.  相似文献   

4.
To form a reference population necessary for genomic selection of dairy cattle, it is important to acquire information on the genetic diversity of the base population. Our report is the first among the studies on breeding of farm animals to implement Wright’s F-statistics for this purpose. Genotyping of animals was performed using BovineSNP50 chip. In total, we genotyped 499 heifers from 13 breeding farms in the Leningrad region. We calculated Weir and Cockerham’s Fst estimate for all pairwise combinations of herds from breeding farms and the values obtained were in the range of 0.016–0.115 with the mean of 0.076 ± 0.002. Theoretical Fst values for the same pairwise combinations of herds were calculated using the ADMIXTURE program. These values were significantly (P < 0.05) higher than Weir and Cockerham’s Fst estimates and fell in the range of 0.063–0.136 with the mean of 0.100 ± 0.001. We discuss the reasons for this discrepancy between the two sets of Fst data. The obtained Fst values were used to identify reliable molecular-genetical differences between the herds. The ADMIXTURE program breaks the pool of 476 heifers into 16 subpopulations, the number of which is close to the number of herds used in the experiment. Results of the comparison between Fst values obtained using SNP markers with published data obtained on microsatellites are in support of the common opinion that microsatellite analysis results in underestimation of Fst values. On the whole, the obtained across-herd Fst values are in the range Fst data reported for cattle breeds. Results of comparison of Fst values with the data on the origin of bulls imported from different countries lead to the conclusion on the expediency of the use of Fst data to assess heterogeneity of the herds. Thus, we have demonstrated that use of Fst data provides the means to assess genetic diversity of cattle herds and is a necessary step in the formation of a reference population for dairy cattle.  相似文献   

5.
The population genetic structure of plant pathogenic fungus Pyrenophora tritici-repentis was examined using microsatellite (SSR) markers. According to the geographical origin of the pathogen populations, they were designated as North Caucasian (S, 33 isolates), northwest (Nw, 39), and Omsk (Om, 43). The populations were analyzed at the nine most polymorphic SSR loci, at which 75 alleles were identified. To characterize the genetic variation within and between populations, the AMOVA algorithm as implemented in the Arlequin v. 3.5 software program was used. The number of alleles per locus ranged from 5 to 12 and their sizes varied within the range from 180 to 400 bp. The mean gene diversity at SSR loci was high for all populations (H = 0.58–0.75). The populations were considerably different in the frequencies of individual alleles of the SSR loci. Most isolates in the populations were represented by unique haplotypes. The within-population variation of the isolates at molecular markers was 86.4%; among the populations, 13.6%. Substantial interpopulation differences were found between the Om and S (Fst = 0.16) and between the Om and Nw (Fst = 0.20) populations, whereas between the S and Nw populations, these differences were small (Fst = 0.05). Thus, it was demonstrated that the population of P. tritici-repentis from Omsk oblast had the independent status of the geographical population; northwest and North Caucasian populations differed in the allelic diversity of SSR loci, and despite the low Fst value (0.05), they also belonged to independent geographical populations.  相似文献   

6.
The European Black Pine (Pinus nigra Arn.) has a long and complex history. Genetic distance and frequency analyses identified three differentiated genetic groups, which corresponded to three wide geographical areas: Westerns Mediterranean, Balkan Peninsula and Asia Minor. These groups shared common ancestors (14.75 and 10.72 Ma). The most recent splits occurred after the Messinian Salinity Crisis (4.37 Ma) and the Early–Middle Pleistocene Transitions (0.93 Ma). The posterior ancestral population size (Na) is 260,000–265,000 individuals. Each pool is further fragmented, with evidence of a phylogeographic structure (N st  > G st ) typically observed in some natural populations from the Western Mediterranean region and the Balkan Peninsula. The laboratory analysis was performed by fragment analysis—i.e. electrophoretic sizing of polymerase chain reaction fragments, combined with the sequencing analysis of 33 % of all individuals as a control. Intense sampling of chloroplast DNA polymorphisms (3154 individuals and 13 markers: SNPs and SSRs) over the full area of the species’ natural distribution indicated moderate among-population variability (G st(nc) ≤ 0.177) in various parts of its range. These results indicate that the natural populations have long migration histories that differ from one another and that they have been strongly phylogeographically affected by complex patterns of isolation, speciation and fragmentation. Long and varying climatic fluctuations in the region of the principal genetic group have been the probable cause of different forest community associations with different successional patterns resulting in interglacial refugia vs. macro long-term refugia.  相似文献   

7.
Electrophoresis in starch gel was used to study the polymorphism of hordeins controlled by loci Hrd A, Hrd B, and Hrd F in 89 accessions of the local barleys from South Arabia (Yemen). Overall, 36 alleles were detected for locus Hrd A; 48 alleles, for Hrd B; and 5 alleles, for Hrd F. The existence of the blocks of hordein components controlled by loci Hrd A and Hrd B was demonstrated. Calculation of genetic distances allows us to conclude that the barley populations from Yemen and Ethiopia are more similar compared with the populations from Egypt. This confirms the hypothesis of Bakhteev on the origin of Ethiopian barleys.  相似文献   

8.
Genetic diversity and differentiation in Quercus rubra remains undescribed for most of the native range. Using 10 highly informative gSSR markers, we genotyped 23 populations (980 trees), from across the native range, at local and rangewide spatial scales. We used a hierarchical Bayesian method to generate population-specific F st estimates. The posterior probabilities of 3 spatial and 19 climate factors revealed that latitude and precipitation in the warmest quarter were the only plausible models for population-specific F st estimates. Population-specific F st estimates increased as a linear function of population latitude (R 2 = 0.745, p < 0.0001), the expected effect of postglacial range expansion. Measures of shared ancestry (pairwise local differentiation) among populations sampled at fine spatial scales within locations also increased with the latitude of the location (R 2 = 0.495, p = 0.014), suggesting an influence on differentiation that could not be attributed to postglacial range expansion. As precipitation in the warmest quarter drives radial growth rate in this species, we propose that growth rate influences generation time, which determines the time required to re-establish migration-drift equilibrium among local regenerating stands. Population substructure analysis detected four groups, only one of which was geographically coherent. Most other populations were moderately admixed. Sampling designs that include both fine and coarse spatial scales can begin to disentangle the effect of past range expansions from the effect of recent disturbances. Accounting for population substructure in this species will require additional studies involving functional genes, interspecific interactions, and species distribution modeling.  相似文献   

9.
To determine the potential for productive efficiency and genetic improvement in the blood clam Tegillarca granosa, four offspring populations (ZZ, ZK, KZ and KK) were produced from a diallel mating of two different geographical stocks (Z and K). The levels of genetic diversity and population structures of four populations were analyzed using 14 polymorphic microsatellites. The results showed that the mean observed heterozygosities (Ho) of reciprocal cross populations (ZK and KZ) was higher than those of pure populations(ZZ and KK). The largest values of genetic differentiation coefficient (Fst?=?0.067) and Nei’s unbiased genetic distance (Dc?=?0.263) were between ZK and KZ, and the smallest (Fst?=?0.020, Dc?=?0.116) were between ZZ and KK, which revealed that the largest genetic divergence was between the two reciprocal cross populations and the smallest was between two pure populations. This study demonstrated that the reciprocal cross populations of T. granosa had an extensive genetic difference and improvement, which may be advantageous for future breeding studies.  相似文献   

10.
Habitat fragmentation due to anthropogenic activities is the major cause of biodiversity loss. Endemic and narrowly distributed species are the most susceptible to habitat degradation. Penstemon scariosus is one of many species whose natural habitat is vulnerable to industrialization. All varieties of P. scariosus (P. scariosus var. albifluvis, P. scariosus var. cyanomontanus, P. scariosus var. garrettii, P. scariosus var. scariosus) have small distribution ranges, but only P. scariosus var. albifluvis is being considered for listing under the Endangered Species Act. We used eight microsatellites or simple sequence repeats (SSRs) loci and two amplified fragment length polymorphism (AFLP) primer combinations to investigate the population genetic structure and diversity of P. scariosus varieties. Moreover, we compared the utility of the two marker systems in conservation genetics and estimated an appropriate sample size in population genetic studies. Genetic differentiation among populations based on Fst ranged from low to moderate (Fst?=?0.056–0.157) and from moderate to high when estimated with Des (Des?=?0.15–0.32). Also, AMOVA analysis shows that most of the genetic variation is within populations. Inbreeding coefficients (Fis) were high in all varieties (0.20–0.56). The Bayesian analysis, STRUCTURE, identified three clusters from SSR data and four clusters from AFLPs. Clusters were not consistent between marker systems and did not represent the current taxonomy. MEMGENE revealed that a high proportion of the genetic variation is due to geographic distance (R2?=?0.38, P?=?0.001). Comparing the genetic measurements from AFLPs and SSRs, we found that AFLP results were more accurate than SSR results across sample size when populations were larger than 25 individuals. As sample size decreases, the estimates become less stable in both AFLP and SSR datasets. Finally, this study provides insight into the population genetic structure of these varieties, which could be used in conservation efforts.  相似文献   

11.
A collection of Puccinia triticina isolates was characterized for polymorphism of microsatellite loci and estimated for their differentiation by geographic origin. The collection included 20 isolates from the Ural region, 31 from West Siberia, 53 from Central Europe, 32 from the Northwest region, 32 from the Volga region, and 40 from the North Caucasus (24 from Dagestan and 16 from Krasnodar and Stavropol). The studied isolates were represented by 65 virulence phenotypes. In the polymorphism analysis of 18 microsatellite loci, 69 genotypes were determined. The index values of genetic distances (F st, R st, KB c) between populations for microsatellite loci indicated differentiation of P. triticina isolates according to geographical origin, and they were clustered into three groups: (1) Asian, (2) European, and (3) North Caucasian. The North Caucasian isolates from Krasnodar and Stavropol regions were closer in similarity to European isolates than the Dagestan ones. Current analysis confirmed the assumption made earlier on the basis of the virulence analysis about the existence of several geographic fungi populations in Russia.  相似文献   

12.
In a nuclear-follower fish foraging association, the follower benefits from food uncovered or flushed out when the nuclear fish disturbs the bottom, while nuclear species generally do not seem to be benefiting. Among nuclear species, eels (anguilliform fish) are known to be one of the most represented groups. Here we investigated the frequency and time duration of foraging associations among the goldspotted eel Myrichthys ocellatus and reef fish in a subtropical marginal reef. In addition, we reviewed nuclear eel species and their followers described in the literature. From a total of 211 goldspotted eels observed, seven follower species were recorded in 19% of the samples. The average time of the following associations per species ranged from 40 to 190 s. Four species were reported for the first time as M. ocellatus followers (Bodianus rufus, B. pulchellus, Stephanolepis hispidus, and Serranus baldwini) and three of them have never been reported in the literature as eel followers (B. pulchellus, S. hispidus, and S. baldwini). The literature describes 13 eel species acting as nuclear for 66 fish species, represented mainly by groupers and sea basses. The size of the eel was not correlated with the size of its follower and neither with the number of described follower species. The nuclear role of eels is likely to be an important component of the trophic ecology of small and medium-sized macrocarnivore fish.  相似文献   

13.
Genetic diversity and geographic distribution of taxon-specific RAPD markers was examined in ten local populations of the house mouse Mus musculus (n = 42). The house mice were generally characterized by moderate genetic variation: polymorphism P 99 = 60%, P 95 = 32.57%; heterozygosity H = 0.12; the observed allele number n a = 1.6; the effective allele number n e = 1.18; the within-population differentiation ?s = 0.388; and Shannon index I = 0.19. The degree of genetic isolation of individual local populations was greatly variable. The genetic subdivision index G st varied from 0.162 to 0.770 at the gene flow of Nm = 2.58?0.149, while the among-population distances D N varied from 0.026 to 0.178. The largest part of the genetic diversity was found among the populations (H T = 0.125), while the within-population diversity was twice lower (H S = 0.06). The samples examined were well discriminated relative to the sets of RAPD markers. The character distribution pattern provided conditional subdivision of the mice into the “western” and the “eastern” groups with the putative boarder along the Baikal Lake. The first group was characterized by the prevalence of the markers typical of M. m. musculus and M. m. domesticus. The second group was characterized by the prevalence of the markers typical of M. m. musculus, M. m. gansuensis, M. m. castaneus, M. m. domesticus, and M. m. wagneri. The genotype of the nominative subspecies M. m. musculus was background for all populations. In the populations examined some of earlier described subspecies-specific molecular markers were found at different frequencies, pointing to the involvement of several subspecies of M. musculus in the process of hybridization.  相似文献   

14.
The population-genetic structure of the bivalve Corbicula japonica from ten estuarine localities in the Primorsky Region was investigated using nine allozyme loci as gene markers. This study revealed spatial genetic heterogeneity between the investigated populations (G st = 0.05); its degree was dependent on the distance between populations. No linkage disequilibrium was found for any pair of loci. The index of genetic similarity between pairs of populations varied from 0.916 to 0.994. The genetic heterogeneity of the C. japonica populations is probably a result of genetic drift balanced by an irregular gene flow. Such an equilibrium may indicate a relatively recent expansion of C. japonica, which may have occurred during the Holocene climatic optimum (about 7500 years ago).  相似文献   

15.
Electrophoresis in starch gel has been used to study the polymorphism of hordeins encoded by loci Hrd A, Hrd B, and Hrd F in 140 local barley populations from the Near East, including 60, 34, 33, 8, and 5 populations from Syria, Jordan, Iraq, Palestine, and Israel, respectively. Fifty-seven Hrd A, 87 Hrd B, and 5 Hrd F alleles have been found. The alleles of these loci considerably differ in frequencies and distribution in populations from different Near Eastern countries. Cluster analysis of the matrix of the frequencies of alleles of hordei-coding locus alleles in barley populations from the Near East, North Africa, Ethiopia, and South Arabia has yielded two clusters. The first cluster includes barley populations from Israel, Palestine, Morocco, Tunisia, Algeria, and Egypt; the second cluster, populations from Iraq, Syria, Jordan, Yemen, and Ethiopia.  相似文献   

16.
In this study, we assessed geographic patterns of genetic variations in nuclear and chloroplast genomes of two related native oaks in Japan, Quercus aliena and Q. serrata, in order to facilitate development of genetic guidelines for transfer of planting stocks for each species. A total of 12 populations of Q. aliena and 44 populations of Q. serrata were analyzed in this study. Genotyping of nuclear microsatellites in Q. aliena was done with only nine populations (n = 212) due to limited numbers of individuals in two populations, while all 12 populations (n = 89) were used in sequencing chloroplast DNA (cpDNA). In Q. serrata, 43 populations (n = 1032) were genotyped by nuclear microsatellite markers, while cpDNA of 44 populations (n = 350) was sequenced. As anticipated, geographic patterns detected in the variations of Q. aliena’s nuclear genome and its chloroplast haplotype distribution clearly distinguished northern and southern groups of populations. However, those of Q. serrata were inconsistent. The geographic distribution of its chloroplast haplotypes tends to show the predicted differentiation between northern and southern lineages, but geographic signals in the genetic structure of its nuclear microsatellites are weak. Therefore, treating northern and southern regions of Japan as genetically distinct transferrable zones for planting stocks is highly warranted for Q. aliena. For Q. serrata, the strong NE-SW geographic structure of cpDNA should be considered.  相似文献   

17.
Patterns of genetic structure and diversity are largely mediated by a species’ ecological niche and sensitivity to climate variation. Some species with narrow ecological niches have been found to exhibit increased population differentiation, limited gene flow across populations, and reduced population genetic diversity. In this study, we examine patterns of population genetic structure and diversity of four bumble bee species that are broadly sympatric, but do not necessarily inhabit the same ecological niche in the Pacific Northwest of the United States. Testing for the effect of isolation by geographic distance (IBD) with linearized F st and D est found that Bombus sylvicola and B. mixtus exhibited significant IBD across populations. In contrast, both B. melanopygus and B. flavifrons, two species that are distributed across a broad elevation gradient, exhibited no IBD, a result further corroborated by Bayesian a priori population assignment tests. Furthermore, we discovered that B. sylvicola populations distributed on the Olympic Peninsula have significantly less average allelic diversity than populations distributed in the Cascade Mountains. Our results suggest that populations distributed in the Olympic Mountains represent a distinct genetic cluster relative to the Cascade Mountains, with B. sylvicola and B. mixtus likely experiencing the greatest degree of population genetic differentiation relative to B. flavifrons and B. melanopygus. While bumble bees are known to co-exist across a diversity of habitats, our results demonstrate that underlying population genetic structure and diversity may not necessarily be similar across species, and are largely governed by their respective niches.  相似文献   

18.
The genetic relationships of mantis shrimp Oratosquilla oratoria between the coastal waters of China and Japan were not well studied. To reveal the genetic differentiation and genetic structure among populations, we collected populations of mantis shrimp O. oratoria from the coastal waters of China and Japan to analyze the mtDNA control region variation. A total of 309 individuals of O. oratoria were collected from 13 localities (11 from China and 2 from Japan) and a segment of mitochondrial DNA control region was sequenced. Three hundred nine haplotypes were defined, yielding a very high haplotype diversity and nucleotide diversity. Two lineages of O. oratoria were revealed and displayed strong differences in the geographical distribution. In the coastal waters of China, the geographic distribution of the two lineages was completely separated by the Yangtze River estuary; however, the lineages showed geographic sympatry in two populations from Japan. Based on the lineage distribution, three groups were defined. There was no significant genetic differentiation among the populations within the three groups, indicating high gene flow within each group. Significant and negative values for Tajima D and Fu’s Fs tests, and mismatch distributions for two lineages indicated population expansion. The present result confirmed that the freshwater outflow from the Yangtze River formed a physical barrier and affected gene exchange. The different distribution patterns of the two lineages in coastal waters of China and Japan indicated that the larvae of O. oratoria were transferred from China to the coastal waters of Japan with a one-way gene flow.  相似文献   

19.
To establish a management plan for endangered and rare species, genetic assessment must first be conducted. The genetic characteristics of plant species are affected by demographic history, reproductive strategy, and distributional range as well as anthropological effects. Abies koreana E. H. Wilson (Pinaceae), Korean fir, is endemic to Korea and found only in sub-alpine areas of the southern Korean Peninsula and Jejudo Island. This species has been designated as critically endangered by the International Union for Conservation of Nature due to a continuous decline in its range and population fragmentation. We genotyped 176 individuals from seven natural populations and two afforested populations on the Korean Peninsula using 19 microsatellite loci. STRUCTURE analysis revealed two genetic clusters in natural populations (F st  = 0.040 and R st  = 0.040) despite low differentiation. We did not detect a significant reduction in genetic diversity or the signature of a genetic bottleneck despite population fragmentation and small population size. We deduced that this species exhibits a metapopulation structure, with the population on Jirisan Mountain acting as a source of genetic diversity for other local small populations on the Korean Peninsula, through contemporary asymmetric gene flow. However, the majority of afforested individuals on the Korean Peninsula originated from a different gene cluster. Thus, we recommend a conservation strategy that maintains two genetically unique clusters.  相似文献   

20.
Using the capillary electrophoresis of ISSR DNA fragments, the genetic structure of the adventitious populations of Helix pomatia L. (Mollusca, Pulmonata) inhabiting the territory of Eastern Europe was studied. A significant decrease in genetic heterogeneity (He = 0.095 ± 0.002) and population differentiation level (Fst = 0.074) was revealed in comparison with similar data obtained using the ISSR method with electrophoretic detection in agarose gel and allozymes in polyacrylamide gel. Similar to other methods, an effect of spatial isolation (RM =–0.476) was found on the basis of regression analysis between genetic and geographical distances. The effective population size, calculated with the help of M. Slatkin’s model, turned out to be the largest of the previously calculated values (Ne = 41.8), which indicates the high viability of the studied groups of Roman snails in newly developed territories.  相似文献   

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