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1.
To evaluate the genetic diversity of a mangrove species and clarify the genetic structure of its populations, we studied nucleotide polymorphism in two DNA regions of Bruguiera gymnorhiza collected from the southern islands of Japan, Thailand, Malaysia, Indonesia, Micronesia, and India. The two DNA sequences were the chloroplast (cp) intergenic spacer between trnL and trnF genes (ca. 300 bp), and a part (ca. 550 bp) of the nuclear gene coding for glyceraldehyde-3-phosphate dehydrogenase (GapCp). Little polymorphism was found within each of the three geographical regions, Pacific Ocean, Bay of Bengal and Arabian Sea. Throughout the vast regions east of the Malay peninsula including Indonesia, Thailand, Micronesia and the southern islands of Japan (Pacific Ocean), essentially only one haplotype (apart from variation in number of a T repeat) was present. A second haplotype was present on the western coast of Malay Peninsula and the eastern coast of India (Bay of Bengal). On the southwest of Malay Peninsula both of these haplotypes were present. Finally a third haplotype was found only on the western coast of India (Arabian Sea). When taken over all geographic populations, total nucleotide variation within the species was large (μ = 0.006, average of the two genes). Our results are consistent with the hypothesis that this low genetic diversity within any local population and differentiation between the different oceans or regions are caused by very low gene flow between each of the different oceans coupled with frequent fluctuation of population sizes due to the change in sea level. The significance of these results is discussed from evolutionary point of the mangrove forests.  相似文献   

2.
The Red Sea has had a profound biogeographic effect on organisms with Afro-Asian distributions, resulting in complex patterns of admixture on the Arabian Peninsula. We investigate the phylogenetic affinities of a monitor lizard (Varanus yemenensis) restricted to the southwestern Arabian Peninsula by sequencing all African monitor species and several Asian monitor species for the mitochondrial gene ND2 and the nuclear marker RAG-1. We find evidence that V. yemenensis is of African origin, being most closely related to the white-throat monitor, V. albigularis, an African species complex distributed from the Horn of Africa to southern Africa. Using divergence-dating analyses, we investigate several biogeographic hypotheses to infer the likely mechanism of colonization of the Arabian Peninsula by this species. Our results reveal that both dispersal across a southern land bridge and overwater dispersal are potential explanations. The patterns observed in V. yemenensis are contrasted with other taxa having similar Afro-Arabian disjunct distributions to better understand the complex biogeographic history of this region.  相似文献   

3.
Red king crab (Paralithodes camtschaticus) was introduced into the Barents Sea in the 1960–1970s. At present, it occurs along the coast from Hammerfest (Northern Norway) to the (northeastern coast of Kola Peninsula). We studied the polymorphism of a mitochondrial gene encoding cytochrome oxidase (COI) and five nuclear microsatellite loci in four samples from the Barents Sea and two donor populations from the Western Kamchatka and Primorye (Russian Pacifics). No decrease in the genetic diversity of the introduced populations was observed. The results of PCA103 locusanalysis but some samples from the Barents Sea significantly differed from the Pacific populations according to the test for population differentiation demonstrated that the sample from Varrangerfjord was highly significantly different from the other five populations. As no significant differences between the other samples were found at this locus. We consider it to be a marker for Varangerfjord population differentiation. Possible reasons of this phenomenon are discussed.  相似文献   

4.
Understanding of fish genetic characterization plays a vital role in the conservation and utilization of fish genetic resources of grouper species. The present study was carried out to assess the genetic diversity and phylogenetic relationships in five grouper species, Epinephelus spp. from eastern Saudi Arabian coast using two molecular marker systems, inter simple sequence repeat (ISSR) and microsatellite (SSR) markers. In total, 219 individuals grouper specimens (Epinephelus tauvina, E. coioides, E. bleekeri, E. malabaricus, and E. areolatus) were genotyped with 10 ISSR and 11 SSR selected primers. The ISSR produced 94 DNA fragments, of which 44 were polymorphic with an average of 2.13 fragment per primer. While SSR primers generated 107 alleles, all of them were polymorphic with an average 9.72 per primer. ISSR and SSR techniques demonstrated a high level of gene diversity and genetic distances illustrated by UPGMA dendrograms among the grouper species. The results proved that the SSR markers were highly informative and efficient in detecting genetic variability and relationships of the Epinephelus spp.  相似文献   

5.
The Collared Kingfisher species complex is the most widespread of the ‘great speciator’ lineages of the Indo‐Pacific. They have shown a remarkable ability to spread and diversify. As a result of this rapid diversification, Todiramphus species are often found in secondary sympatry. In Southeast Sulawesi, Indonesia, two Todiramphus species are present, the breeding resident Collared Kingfisher Todiramphus chloris and the overwintering migratory Sacred Kingfisher Todiramphus sanctus. We investigated the effect of isolation on these closely related species by comparing their populations on mainland Sulawesi and its larger continental islands, with populations on the small, oceanic Wakatobi Islands. Within our wider analysis we provide further support for the distinctiveness of the Sulawesi Collared Kingfisher population, perhaps isolated by the deep water barrier of Wallace's line. Within Sulawesi we found that populations of Collared Kingfisher on the Wakatobi Islands had diverged from those on mainland Sulawesi, differing both in morphology and in mitochondrial DNA. In contrast, there was no divergence between Sacred Kingfisher populations in either morphology or mitochondrial DNA. We propose that a difference in habitat occupied by Collared Kingfisher populations between the mainland and continental islands vs. oceanic islands has caused this divergence. Mainland Collared Kingfishers are predominately found inland, whereas Wakatobi Collared Kingfishers are also found in coastal habitats. The larger body size of Wakatobi Collared Kingfisher populations may be a result of increased competition with predominantly coastal Sacred Kingfisher populations. The uniform nature of Sacred Kingfisher populations in this region probably reflects their consistent habitat choice (coastal mangrove) and their migratory nature. The demands of their breeding range are likely to have an even stronger selective influence than their Sulawesi wintering range, limiting their scope for divergence. These results provide insight into the adaptability of the widespread Todiramphus lineage and are evidence of the need for further taxonomic revision of Collared Kingfisher populations.  相似文献   

6.

Background

The mitochondrial gene COI has been widely used by taxonomists as a standard DNA barcode sequence for the identification of many animal species. However, the COI region is of limited use for identifying certain species and is not efficiently amplified by PCR in all animal taxa. To evaluate the utility of COI as a DNA barcode and to identify other barcode genes, we chose the aphid subfamily Lachninae (Hemiptera: Aphididae) as the focus of our study. We compared the results obtained using COI with two other mitochondrial genes, COII and Cytb. In addition, we propose a new method to improve the efficiency of species identification using DNA barcoding.

Methodology/Principal Findings

Three mitochondrial genes (COI, COII and Cytb) were sequenced and were used in the identification of over 80 species of Lachninae. The COI and COII genes demonstrated a greater PCR amplification efficiency than Cytb. Species identification using COII sequences had a higher frequency of success (96.9% in “best match” and 90.8% in “best close match”) and yielded lower intra- and higher interspecific genetic divergence values than the other two markers. The use of “tag barcodes” is a new approach that involves attaching a species-specific tag to the standard DNA barcode. With this method, the “barcoding overlap” can be nearly eliminated. As a result, we were able to increase the identification success rate from 83.9% to 95.2% by using COI and the “best close match” technique.

Conclusions/Significance

A COII-based identification system should be more effective in identifying lachnine species than COI or Cytb. However, the Cytb gene is an effective marker for the study of aphid population genetics due to its high sequence diversity. Furthermore, the use of “tag barcodes” can improve the accuracy of DNA barcoding identification by reducing or removing the overlap between intra- and inter-specific genetic divergence values.  相似文献   

7.
Four population samples of Pacific capelin Mallotus villosus catervarius (Pennat, 1784) from geographically distant localities in the Sea of Okhotsk, Tauy Bay and the eastern coast of the Sakhalin Island, were examined using PCR-RFLP analysis of three mitochondrial DNA regions (A8/A6/COIII/ND3, ND3/ND4L/ND4, and ND5/ND6). The nucleotide divergence of mtDNA sequences among the samples, as well as the analysis of geographic heterogeneity of the haplotype frequencies and quantitative estimation of genetic differentiation performed by means of AMOVA, showed that the samples examined belonged to one panmictic population. Genealogic analysis of the mtDNA variation structure was carried out. It was demonstrated that the high level of haplotype diversity (0.9639 ± 0.00015) along with the low level of nucleotide diversity (0.003818 ± 0.0000003) pointed to the exponential rate of population growth of the capelin from the Sea of Okhotsk, which rather recently in its evolutionary history faced the bottleneck effect.  相似文献   

8.
9.
We supplement a previously published mitochondrial DNA data set of grass snake sequences (ND1, ND2, ND4, cyt b, in total 3,806 bp) with sequences of Corso-Sardinian and Tuscan specimens and infer their phylogeny using Bayesian, maximum likelihood and maximum parsimony methods. In addition, we estimate divergence times of grass snake clades using a relaxed molecular clock calibrated with fossil evidence, and, in a second approach, the post-Messinian reopening of the Strait of Gibraltar. Recently it was suggested that Corso-Sardinian grass snakes represent a distinct species: Natrix cetti. All tree-building methods revealed well-supported branching patterns and deep divergences among grass snakes. However, sequences of N. natrix were consistently paraphyletic with respect to Corso-Sardinian sequences. The sister group of Corso-Sardinian grass snakes is a clade embracing N. n. helvetica and N. n. lanzai. Extensive gene flow between N. n. helvetica and a more distantly related subspecies (N. n. natrix) is well known, which is why we conclude that the status of Corso-Sardinian grass snakes as subspecies of N. natrix should be reinstated. Many currently recognized grass snake subspecies conflict with mitochondrial clades, suggestive of inappropriate morphological taxon delineation and mitochondrial introgression. Divergences among grass snakes are old, and the results of the two independent dating approaches are largely congruent. Accordingly, the Alpine orogenesis seems to have caused the origin of the oldest clade, corresponding to Iberian N. n. astreptophora. The formation of Corso-Sardinian grass snakes was dated to the Early Pliocene and could result from post-Messinian flooding of the Mediterranean Basin. Another deeply divergent clade of approximately the same age, endemic in central and northern Europe, suggests the Pleistocene survival of grass snakes north of the Alps. At least one glacial refuge in which old lineages survived Pleistocene cold periods was located on each of the three major southern European peninsulas and in Anatolia. Due to pronounced sequence divergences among Italian and southern Swiss grass snakes, we hypothesize multiple refugia south of the Alps and in the Apennine Peninsula, and there is evidence for two refuges on the Balkan Peninsula.  相似文献   

10.
The complete mitochondrial genome (mitogenome) of the Ailanthus silkmoth, Samia cynthia cynthia (Lepidoptera: Saturniidae) was determined. The circular genome is 15,345 bp long, and presents a typical gene organization and order for sequenced mitogenomes of Bombycidea species. The nucleotide composition of the genome is highly A+T biased, accounting for 79.86%. The AT skew of the genome is slightly negative, indicating the occurrence of more Ts than As, as found in other Saturniidae species. All protein-coding genes (PCGs) are initiated by ATN codons, except for COI and COII, which are tentatively designated by CGA and GTG, respectively, as observed in other insects. Four of 13 PCGs, including COI, COII, ATP6, and ND3, harbor the incomplete termination codons, T or TA. With an exception for tRNASer(AGN), all other tRNAs can form a typical clover-leaf structure of mitochondrial tRNA. The 359 bp A+T-rich region of S. c. cynthia contains non-repetitive sequences, but harbors several features common to the Bombycidea insects, including the motif ATAGA followed by a poly-T stretch of 19 bp, a microsatellite-like (AT)7 element preceded by the ATTTA motif, and a poly-A element upstream tRNAMet. The phylogenetic analyses support the morphology-based current hypothesis that Bombycidae and Saturniidae are monophyletic. Our result confirms that Saturniini and Attacini form a reciprocal monophyletic group within Saturniidae.  相似文献   

11.
In this study, DNA barcoding was used in the identification of potential biological control agents of sunn pest adult parasitoid species, including Eliozeta helluo (F.), Phasia subcoleoptrata (L.), Ectophasia crassipennis (F.) and Elomyia lateralis (Meig). DNA analyses were assessed by sequencing cytochrome c oxidase subunit I (COI) gene. The obtained sequences were analyzed in terms of nucleotide composition, nucleotide pair frequency and haplotype diversity. Genetic divergence among haplotypes was estimated by constructing genetic distance matrix using DNA sequence variations, by Kimura 2-parameter model. Variable sites and average variations of the sequenced 603 base pair long DNA fragment were calculated. All COI barcodes were matched with reference sequences of expected species according to morphological identification. Neighbor-joining tree was drawn based on DNA barcodes and all the specimens clustered in agreement with their taxonomic classification at species level. The evolutionary history inferred using the UPGMA method indicated two distinct mitochondrial haplotype lineages. The genetic variation between sunn pest adult parasitoids will be useful in sunn pest management, regulatory and environmental applications.  相似文献   

12.
对21种帘蛤科贝类线粒体细胞色素c氧化酶亚基Ⅰ(cytochrome c oxidase subunit I,COI)基因核苷酸序列进行了分析,以探讨这一序列在种质鉴定、分子系统发生研究中的应用价值。测序结果表明,所有物种扩增片段长度均为707 bp(含引物),序列A+T含量(62.4%—67.8%)明显高于G+C含量。物种间共有变异位点379个,其中简约信息位点334个;此区段共编码235个氨基酸,种间共有氨基酸变异位点100个。以COI基因片段序列为标记,用中国蛤蜊(Mactra chinensis)作外群,构建了35种帘蛤科贝类(其中14种贝类COI序列从GenBank下载)的系统发生树,结合拓扑结构分析和序列比对分析,结果表明:支持将短文蛤(Meretrix petechinalis)和丽文蛤(M.lusoria)订为文蛤(M.meretrix)的同物异名的观点,建议将丽文蛤和短文蛤订为文蛤的地理亚种;支持将薄片镜蛤(Dosinia corrugata)和D.angulosa订为2个独立种的观点;认为将波纹巴非蛤(Paphia undulata)和织锦巴非蛤(P.textile)订为2个独立种是合适的。COI基因序列含有丰富的遗传信息,适合作为帘蛤科贝类种群遗传结构和系统发生研究的分子标记。  相似文献   

13.
Surveys of larval diversity consistently increase biodiversity estimates when applied to poorly documented groups of marine invertebrates such as phoronids and hemichordates. However, it remains to be seen how helpful this approach is for detecting unsampled species in well‐studied groups. Echinoids represent a large, robust, well‐studied macrofauna, with low diversity and low incidence of cryptic species, making them an ideal test case for the efficacy of larval barcoding to discover diversity in such groups. We developed a reference dataset of DNA barcodes for the shallow‐water adult echinoids from both coasts of Panama and compared them to DNA sequences obtained from larvae collected primarily on the Caribbean coast of Panama. We sequenced mitochondrial cytochrome c oxidase subunit I (COI) for 43 species of adult sea urchins to expand the number and coverage of sequences available in GenBank. Sequences were successfully obtained for COI and 16S ribosomal DNA from 272 larvae and assigned to 17 operational taxonomic units (OTUs): 4 from the Pacific coast of Panama, where larvae were not sampled as intensively, and 13 from the Caribbean coast. Of these 17 OTUs, 13 were identified from comparisons with our adult sequences and belonged to species well documented in these regions. Another larva was identified from comparisons with unpublished sequences in the Barcode of Life Database (BOLD) as belonging to Pseudoboletia, a genus scarcely known in the Caribbean and previously unreported in Panama. Three OTUs remained unidentified. Based on larval morphology, at least two of these OTUs appeared to be spatangoids, which are difficult to collect and whose presence often goes undetected in standard surveys of benthic diversity. Despite its ability to capture unanticipated diversity, larval sampling failed to collect some species that are locally common along the Caribbean coast of Panama, such as Leodia sexiesperforata, Diadema antillarum, and Clypeaster rosaceus.  相似文献   

14.
Dromedary camels (Camelus dromedarius) are widespread in the desert and semi-desert areas of Africa, the Arabian Peninsula, some parts of southwest Asia and Australia. In the Arabian Peninsula, these well-adapted species have been classified based on their ecology into Desert camels, found mainly in the north and center of the Peninsula, Mountain camels, distributed along the west and south of the Peninsula, and Beach camels, populating the west to southwest of the Peninsula. Here, we aimed to investigate the genetic relationship between 386 camels corresponding to 12 dromedary populations from different geographical locations and ecology in the Arabian Peninsula with the genotyping of 17 microsatellite loci. No significant deviation was observed in heterozygosity, allelic richness, Fis (inbreeding coefficient) among the studied populations had a mean value of 0.5849, 4.808 and 0.04, respectively. A mean Fst (fixation index) value of 0.0304 was calculated for the various populations with the highest value obtained between racing Omani and Awarik camel populations (0.079). Both the neighbor-joining phylogenetic tree and the STRUCTURE analysis divided the populations into three different groups corresponding to their Arabian Peninsula geographic location (North, Central and West, South-West, and South-East of the Arabian Peninsula), rather than their ecological classification, with a high level of genetic admixture and gene flow among them. Investigating the genetic relationship of dromedary populations in the Arabian Peninsula can be considered as the first milestone to conserve this well-adapted species. The results obtained here need to be further validated using whole genome sequencing data.  相似文献   

15.
16.
The complete mitochondrial genome of Ampittia dioscorides (Lepidoptera: Hesperiidae) was determined. The sequenced genome is a circular molecule of 15313 bp, containing 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and an A + T-rich region. The gene arrangements and transcribing directions are identical to those in most of the reported lepidopteran mitogenomes. The base composition of the whole genome and genes or regions are also similar to those in other lepidopteran species. All the PCGs are initiated by typical ATN codons; the exception being COI, which begins with a CGA codon. Eight genes (ND2, ATPase8, ATPase6, COIII, ND5, ND4L, ND6, and Cytb) end with a TAA stop codon, and two genes (ND1 and ND3) end with TAG. The remaining three genes (COI and COII, which end with TA-, and ND4, which ends with T-) have incomplete stop codons. All tRNAs have the typical clover-leaf structure of mitochondrial tRNAs, with the exception of tRNASer(AGY). On the basis of the concatenated nucleotide and amino acid sequences of the 13 PCGs and wingless gene of 22 butterfly species, maximum parsimony (MP) and Bayesian inference (BI) trees were constructed, respectively. Both MP and BI trees had the same topological structure: ((((Nymphalidae + Danaidae) + Lycaenidae) + Pieridae) + Papilionidae) + Hesperiidae). The results provide support for Hesperiidae as a superfamily-level taxon.  相似文献   

17.
A fragment of the mitochondrial COI gene from isolates of several echinoderm species was sequenced. The isolates were from three species of starfish from the Asteriidae family (Asterias amurensis and Aphelasterias japonica collected in the Sea of Japan and Asterias rubens collected in the White Sea) and from the sea urchin Echinocardium cordatum (family Loveniidae) collected in the Sea of Japan. Additionally, regions including internal transcribed spacers and 5.8S rRNA (ITS1–5.8S rDNA–ITS2) were sequenced for the three studied starfish species. Phylogenetic analysis of the obtained COI sequences together with earlier determined homologous COI sequences from Ast. forbesii, Ast. rubens, and Echinocardium laevigaster from the North Atlantic and E. cordatum from the Yellow and North Seas (GenBank) placed them into strictly conspecific clusters with high bootstrap support (99% in all cases). Only two exceptions–Ast. rubens DQ077915 sequence placed with the Ast. forbesii cluster and Aph. japonica DQ992560 sequence placed with the Ast. amurensis cluster–were likely results of species misidentification. The intraspecific polymorphism for the COI gene within the Asteriidae family varied within a range of 0.2-0.9% as estimated from the genetic distances. The corresponding intrageneric and intergeneric values were 10.4-12.1 and 21.8-29.8%, respectively. The interspecific divergence for the COI gene in the sea urchin of Echinocardium genus (family Loveniidae) was significantly higher (17.1-17.7%) than in the starfish, while intergeneric divergence (14.6-25.7%) was similar to that in asteroids. The interspecific genetic distances for the nuclear transcribed sequences (ITS1–5.8S rDNA–ITS2) within the Asteriidae family were lower (3.1-4.5%), and the intergeneric distances were significantly higher (32.8-35.0%), compared to the corresponding distances for the COI gene. These results suggest that the investigated molecular-genetic markers could be used for segregation and identification of echinoderm species.  相似文献   

18.
A total of 103 barcode (mitochondrial COI) sequences were newly provided for 77 forest insect pests from 66 genera belonging to Coleoptera, Hemiptera, and Lepidoptera. All 77 species had distinct COI sequences, revealing low intraspecific genetic divergence (< 1.20%) and high interspecific genetic divergence (> 7.30%). Among the 66 genera, 32 COI sequences of 25 species belonging to 16 genera were compared with 280 COI sequences of 117 species belonging to the same 16 genera archived in GenBank, showing that most species were clearly distinguished by barcode sequences. Based on these results, we conclude that a DNA barcode is effective for identifying forest insect pest species.  相似文献   

19.
The gastropod Hexaplex trunculus is widely distributed in a relatively large range of habitats, but has no dispersal stage. We investigated its genetic structure across its distribution range, from Mediterranean Sea to adjacent Atlantic coasts, by sequencing mitochondrial DNA portions of the NADH dehydrogenase gene ND2 (420 pb) and the internal transcribed spacer ITS2 (450 pb). Our results suggested a significant genetic variability of ND2 (π = 0.009 and Hd = 0.629) and low variability of the ITS2 sequences. A strong phylogeographic break, separated the Aegean populations from those of Western/Eastern Mediterranean and the Atlantic ones, was founded. The tow lineages may have been separated by vicariance events due to the Peloponnese break that separates the Aegean populations from other populations and was maintained until now by the quasi-circular anticyclonic front associated to the straits of Cretan Arc of the Peloponnesian Peninsula. Tunisian coasts appear particularly diverse since the two divergent lineages co-occured. These results may have management consequences since H. trunculus is a high commercial value harvested species.  相似文献   

20.
We investigated the phylogeography and subspecies classification of the ostrich (Struthio camelus) by assessing patterns of variation in mitochondrial DNA control region (mtDNA-CR) sequence and across fourteen nuclear microsatellite loci. The current consensus taxonomy of S. camelus names five subspecies based on morphology, geographic range, mtDNA restriction fragment length polymorphism and mtDNA-CR sequence analysis: S. c. camelus, S. c. syriacus, S. c. molybdephanes, S. c. massaicus and S. c. australis. We expanded a previous mtDNA dataset from 18 individual mtDNA-CR sequences to 123 sequences, including sequences from all five subspecies. Importantly, these additional sequences included 43 novel sequences of the red-necked ostrich, S. c. camelus, obtained from birds from Niger. Phylogeographic reconstruction of these sequences matches previous results, with three well-supported clades containing S. c. camelus/syriacus, S. c. molybdophanes, and S. c. massaicus/australis, respectively. The 14 microsatellite loci assessed for 119 individuals of four subspecies (all but S. c. syriacus) showed considerable variation, with an average of 13.4 (±2.0) alleles per locus and a mean observed heterozygosity of 55.7 (±5.3)%. These data revealed high levels of variation within most subspecies, and a structure analysis revealed strong separation between each of the four subspecies. The level of divergence across both marker types suggests the consideration of separate species status for S. c. molybdophanes, and perhaps also for S. c. camelus/syriacus. Both the mtDNA-CR and microsatellite analyzes also suggest that there has been no recent hybridization between the subspecies. These findings are of importance for management of the highly endangered red-necked subspecies (S. c. camelus) and may warrant its placement onto the IUCN red list of threatened animals.  相似文献   

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