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1.
The gecko genus Phyllopezus occurs across South America's open biomes: Cerrado, Seasonally Dry Tropical Forests (SDTF, including Caatinga), and Chaco. We generated a multi-gene dataset and estimated phylogenetic relationships among described Phyllopezus taxa and related species. We included exemplars from both described Phyllopezus pollicaris subspecies, P. p. pollicaris and P. p.przewalskii. Phylogenies from the concatenated data as well as species trees constructed from individual gene trees were largely congruent. All phylogeny reconstruction methods showed Bogertia lutzae as the sister species of Phyllopezus maranjonensis, rendering Phyllopezus paraphyletic. We synonymized the monotypic genus Bogertia with Phyllopezus to maintain a taxonomy that is isomorphic with phylogenetic history. We recovered multiple, deeply divergent, cryptic lineages within P. pollicaris. These cryptic lineages possessed mtDNA distances equivalent to distances among other gekkotan sister taxa. Described P. pollicaris subspecies are not reciprocally monophyletic and current subspecific taxonomy does not accurately reflect evolutionary relationships among cryptic lineages. We highlight the conservation significance of these results in light of the ongoing habitat loss in South America's open biomes.  相似文献   

2.
Phylogenetic relationships among members of the freshwater fish tribe Girardinini were inferred to test existing colonization and diversification hypotheses for this group in the Caribbean. The genetic material examined was mitochondrial (cytochrome b, 1140 bp) and nuclear (RAG-1 and beta-actin, 2450 bp) DNA from 161 specimens representing 44 ingroup and three outgroup taxa. Our mtDNA and combined data matrix (mtDNA+nuclear DNA) results rendered a well-supported phylogeny for the tribe Girardinini and suggest the need to review the group's current taxonomy. From the data presented here, it may be inferred that the Girardinini diverged from other poeciliid fishes approximately 62 Mya ago in the Palaeocene period. This estimate, however, conflicts with the hypothesis that today's vertebrate fauna is the result of the more recent colonization of the Antillean islands during the Early Oligocene (35-33 Mya ago). The isolation of western, central and eastern Cuba during the Miocene and that of the Juventud Island and Guanahacabibes Peninsula during the Pliocene, are the main geologic events that could have promoted speciation in this group.  相似文献   

3.
The anuran tribe Paini, family Dicroglossidae, is known in this group only from Asia. The phylogenetic relationships and often the taxonomic recognition of species are controversial. In order to stabilize the classification, we used approximately 2100 bp of nuclear (rhodopsin, tyrosinase) and mitochondrial (12S, 16S rRNA) DNA sequence data to infer the phylogenetic relationships of these frogs. Phylogenetic trees reconstructed using Bayesian inference and maximum parsimony methods supported a monophyletic tribe Paini. Two distinct groups (I,II) were recovered with the mtDNA alone and the total concatenated data (mtDNA+nuDNA). The recognition of two genera, Quasipaa and Nanorana, was supported. Group I, Quasipaa, is widespread east of the Hengduan Mountain Ranges and consists of taxa from relatively low elevations in southern China, Vietnam and Laos. Group II, Nanorana, contains a mix of species occurring from high to low elevation predominantly in the Qinghai-Tibetan Plateau and Hengduan Mountain Ranges. The occurrence of frogs at high elevations appears to be a derived ecological condition. The composition of some major species groups based on morphological characteristics strongly conflicts with the molecular analysis. Some possible cryptic species are indicated by the molecular analyses. The incorporation of genetic data from type localities helped to resolve some of the taxonomic problems, although further combined analyses of morphological data from type specimens are required. The two nuDNA gene segments proved to be very informative for resolving higher phylogenetic relationships and more nuclear data should be explored to be more confident in the relationships.  相似文献   

4.
We present a phylogenetic hypothesis and novel, rank-free classification for all extant species of softshell turtles (Testudines:Trionychidae). Our data set included DNA sequence data from two mitochondrial protein-coding genes and a approximately 1-kb nuclear intron for 23 of 26 recognized species, and 59 previously published morphological characters for a complimentary set of 24 species. The combined data set provided complete taxonomic coverage for this globally distributed clade of turtles, with incomplete data for a few taxa. Although our taxonomic sampling is complete, most of the modern taxa are representatives of old and very divergent lineages. Thus, due to biological realities, our sampling consists of one or a few representatives of several ancient lineages across a relatively deep phylogenetic tree. Our analyses of the combined data set converge on a set of well-supported relationships, which is in accord with many aspects of traditional softshell systematics including the monophyly of the Cyclanorbinae and Trionychinae. However, our results conflict with other aspects of current taxonomy and indicate that most of the currently recognized tribes are not monophyletic. We use this strong estimate of the phylogeny of softshell turtles for two purposes: (1) as the basis for a novel rank-free classification, and (2) to retrospectively examine strategies for analyzing highly homoplasious mtDNA data in deep phylogenetic problems where increased taxon sampling is not an option. Weeded and weighted parsimony, and model-based techniques, generally improved the phylogenetic performance of highly homoplasious mtDNA sequences, but no single strategy completely mitigated the problems of associated with these highly homoplasious data. Many deep nodes in the softshell turtle phylogeny were confidently recovered only after the addition of largely nonhomoplasious data from the nuclear intron.  相似文献   

5.
Abstract.  The phylogeny of Iberian Aphodiini species was reconstructed based on morphology. Wing venation, mouthparts, male and female genitalia, and external morphology provided ninety-four characters scored for ninety-three Aphodiini species. Phylogenetic analyses were based on maximum parsimony and Bayesian inference criteria. Maximum parsimony consensus trees recovered Acrossus species as a sister group of the remaining Aphodiini, followed by two other branches, one including Neagolius , Plagiogonus , Ahermodontus and Ammoecius species, and the other including Oxyomus , Nimbus , Heptaulacus and Euheptaulacus species. The remaining studied taxa clustered in an unresolved group. Bayesian inference trees recovered Acrossus as the sister group of the remaining Iberian Aphodiini, followed by Colobopterus erraticus and the rest of the Iberian Aphodiini, but this latter branch was unresolved. The general lack of statistical support for the inferred phylogenetic relationships at terminal nodes using both maximum parsimony and Bayesian inference suggests that variation in morphological characters useful for phylogenetic inference in the present study is small, perhaps as a consequence of a radiation event occurring at the origin of the tribe. A probable evolutionary pattern for Aphodiini is proposed which infers six groups, namely Acrossian, Ammoecian, Oxyomian, Aphodian s.str., Colobopteran and Aphodian s.l. clades.  相似文献   

6.
Evidence from morphology is used to infer the phylogeny of the superfamily Poecilioidea using other cyprinodontoid fishes as outgroups. The three equally most parsimonious trees resulting from the phylogenetic analysis support the monophyly of the families Anablepidae and Poeciliidae with respect to each other, but the previous taxonomy within the Poeciliinae is not consistent with the resultant phylogenetic trees. The Poeciliidae is recognized with three subfamilies: the Aplocheilichthyinae containing solely Aplocheilichthys spilauchen , the Procatopodinae containing Fluviphylax (Fluviphylacini) and the African lamp-eyed killifishes (Procatopodini), and the Poeciliinae. The inferred hierarchical relationships of included suprageneric taxa are: ((Oxyzygonectinae, Anablepinae) (Aplocheilichthyinae ((Fluviphylacini, Procatopodini) (Alfarini (Priapellini (Gambusini (Heterandrini (Cnesterodontini (Girardini, Poeciliini))))))))). The tribe Alfarini is resurrected and a new tribe, the Priapellini, is described. Tomeurus gracilis is not the most basal poeciliine, and facultative viviparity in Tomeurus is not a plesiomorphic intermediate condition of viviparity retained from the common ancestor of poeciliines. Facultative viviparity in Tomeurus is the result of an evolutionary loss of obligate viviparity. Tomeurus gracilis is recognized as a member of the tribe Cnesterodontini. Lamprichthys tanganicus and Micropanchax pelagicus are not sister taxa, and the pelagic lacustrine habits of these two species are inferred to have evolved independently. Based on the principles of vicariance biogeography, the origin of the Poecilioidea is inferred to have occurred before the separation of Africa and South America.  相似文献   

7.
Liang R  Zhuo X  Yang G  Luo D  Zhong S  Zou J 《Mitochondrial DNA》2012,23(4):264-277
Haemulidae species are morphologically diversified fishes with wondrous and changeable coloration. These species are prevalent in global tropical, subtropical, and temperate inshore reef areas. Previous morphological classification within Haemulidae and some related families was problematic, and no comprehensive molecular evaluation was conducted on these groups. In this study, we revealed the first molecular phylogenetic analysis involving representative species within Haemulidae and the relevant families (Nemipteridae and Teraponidae). The analysis was performed using both mitochondrial DNA (16S rRNA) and nuclear DNA (TMO-4c4) genes to construct maximum parsimony, maximum likelihood, and Bayesian analysis tree topologies. The molecular phylogeny recovered well-resolved relationships within Haemulidae species and the problematic taxa. In the trees, the Haemulidae species (except for genus Hapalogenys) were divided into two distinct sister lineages, including grunts (Haemulinae) and sweetlips (Plectorhynchinae). Hapalogenys was positioned outside the major Haemulidae tribe and formed an independent group, which challenged the traditional taxonomy that Hapalogenys was classified into Haemulidae. The results did agree with most current studies that Hapalogenys was only distantly related to Haemulidae and could potentially be removed from this family. Additionally, the genus Diagramma was observed to be tightly grouped inside the clade Plectorhinchus, indicating its highly close affinity within Plectorhinchus. Regarding interfamily relationships, the phylogenetic constructions suggested distant relationships within two pairs: between Scolopsis and Haemulidae and between Teraponidae and Haemulidae. Scolopsis was revealed to be highly close with Nemipteridae, and Teraponidae was clustered in an independent group, which was in accordance with most current taxonomic studies.  相似文献   

8.
The first comprehensive phylogenetic analyses of the most diverse subfamily of plant bugs, Mirinae, is presented in this study, for 110 representative taxa based on total evidence analysis. A total of 85 morphological characters and 3898 bp of mitochondrial (16S, COI) and nuclear (18S, 28S) sequences were analysed for each partitioned and combined dataset based on parsimony, maximum likelihood and Bayesian inference. Major results obtained in this study include monophyly of the tribe Mecistoscelini. The largest tribe, Mirini, was recovered as polyphyletic, and Stenodemini was recovered as paraphyletic. The clade of Stenodemini + Mecistoscelini is the sister group of the remaining Mirinae. The monophyly of two complexes composed of superficially similar genera were tested; the Lygus complex was recovered as nonmonophyletic, and the Adelphocoris–Creontiades–Megacoelum complex was confirmed to be monophyletic. The generic relationships of the main clades within each tribe based on the phylogeny, as well as their supported morphological characters, are discussed.  相似文献   

9.
Mitochondrial sequences are widely used for species identification and for studying phylogenetic relationships among closely related species or populations of the same species. However, many studies of mammals have shown that the maternal history of the mitochondrial genome can be discordant with the true evolutionary history of the taxa. In such cases, the analyses of multiple nuclear genes can be more powerful for deciphering interspecific relationships.Here, we designed primers for amplifying 13 new exon-primed intron-crossing (EPIC) autosomal loci for studying shallow phylogeny and taxonomy of Laurasiatherian mammals. Three criteria were used for the selection of the markers: gene orthology, a PCR product length between 600 and 1200 nucleotides, and different chromosomal locations in the bovine genome. Positive PCRs were obtained from different species representing the orders Carnivora, Cetartiodactyla, Chiroptera, Perissodactyla and Pholidota.The newly developed markers were analyzed in a phylogenetic study of the tribe Bovini (the group containing domestic and wild cattle, bison, yak, African buffalo, Asian buffalo, and saola) based on 17 taxa and 18 nuclear genes, representing a total alignment of 13,095 nucleotides. The phylogenetic results were compared to those obtained from analyses of the complete mitochondrial genome and Y chromosomal genes. Our analyses support a basal divergence of the saola (Pseudoryx) and a sister-group relationship between yak and bison. These results contrast with recent molecular studies but are in better agreement with morphology. The comparison of pairwise nucleotide distances shows that our nuDNA dataset provides a good signal for identifying taxonomic levels, such as species, genera, subtribes, tribes and subfamilies, whereas the mtDNA genome fails because of mtDNA introgression and higher levels of homoplasy. Accordingly, we conclude that the genus Bison should be regarded as a synonym of Bos, with the European bison relegated to a subspecies rank within Bos bison. We compared our molecular dating estimates to the fossil record in order to propose a biogeographic scenario for the evolution of Bovini during the Neogene.  相似文献   

10.
The phylogenetic relationships among the genera of the tribe Papionini are inferred using a taxonomic congruence approach in which gene trees derived for eight unlinked genetic sequence datasets are compared. Population genetics theory predicts that species relationships will be revealed with greater probability when the topology of gene trees from many unlinked loci are found to be congruent. The theory underlying this approach is described. Monophyly of the mangabeys is not supported by any of the gene trees; instead, they are polyphyletic with Cercocebus found to be the sister taxon to Mandrillus in five gene trees (with no conflicting trees), and Lophocebus found to be closely related to Papio and/or Theropithecus in all trees. Theropithecus and Papio are not strongly supported as sister taxa (present in one or two trees only);Lophocebus and Papio are supported as sister taxa in the majority of trees. A close relationship between Mandrillus and Papio is not supported in any of the trees.The relationships among Papio, Lophocebus, and Theropithecus cannot be resolved by congruence, probably due to the short time interval estimated between their divergences. The mtDNA COII sequences are used to estimate divergence dates within the papionins. The internode between the divergences of these species is estimated to be between 290 ka and 370 ka. Lastly, the evolution of morphological features such as long faces, suborbital facial fossae, and terrestrial skeletal adaptations is discussed.  相似文献   

11.
This is the first molecular study to trace the evolutionary transition in substrate preference across a primate radiation. We surveyed 20 guenons (tribe Cercopithecini) and 4 outgroup taxa for two Y-chromosomal genes, TSPY ( approximately 2240 bp) and SRY ( approximately 780 bp), and one X-chromosomal intergenic region ( approximately 1600 bp) homologous to a fragment of human Xq13.3. Parsimony and maximum likelihood analyses of the sex chromosomal datasets consistently cluster the three terrestrial taxa, Cercopithecus aethiops, Cercopithecus lhoesti, and Erythrocebus patas, into a group that is reciprocally monophyletic with a clade of arboreal Cercopithecus spp. Given that the common ancestor of the two clades was most likely an arboreal taxon, this phylogenetic pattern suggests the transition to terrestriality occurred only once among the extant guenons. This pattern also indicates that the genus Cercopithecus is paraphyletic, as presently defined, and calls for taxonomic revision so that the nomen describes a strictly monophyletic group. We outline four acceptable taxonomic schemes and suggest that the most appropriate is to reassign C. aethiops, C. lhoesti, and E. patas to the resurrected genus Chlorocebus. Finally, while the phylogeny and taxonomy of terrestrial guenons were the focus of this study, the X-chromosome sequences presented here represent the first molecular evidence to unambiguously place Allenopithecus nigroviridis as the basal lineage of the tribe Cercopithecini.  相似文献   

12.
A phylogeny of 19 of the 22 currently recognized species of Myiarchus tyrant-flycatchers is presented. It is based on 842bp of mitochondrial DNA (mtDNA) sequences from the ATPase subunit 8 and ATPase subunit 6 genes. Except for the morphologically distinct M. semirufus, mtDNAs of the remaining 18 species fall into either of two clades. One comprises predominantly Caribbean and Central and North American taxa (Clade I), and the other is of predominantly South American taxa (Clade II). The phylogeny is only very broadly concordant with some vocal characters and also with the limited morphological diversity for which the group is well known. Paraphyly in several species (M. swainsoni, M. tuberculifer, M. ferox, M. phaeocephalus, M. sagrae, M. stolidus) suggests that morphological evolution, albeit resulting in limited morphological diversity, has been more rapid than that of mtDNA, or that current taxonomy is faulty, or both. A South American origin for Myiarchus is likely. Dispersal and vicariance both appear to have been involved in generating the present-day distribution of some species. Relatively recent dispersal events out of South America are inferred to have brought species of Clades I and II into broad sympatry. Jamaica has been colonized independently at least twice by members of Clades I and II. The phylogeny brings a historical perspective that in turn suggests that ecological study of closely related species from within each major clade where they are sympatric will be especially rewarding.  相似文献   

13.
It has proven remarkably difficult to obtain a well-resolved and strongly supported phylogeny for horned lizards (Phrynosoma) because of incongruence between morphological and mitochondrial DNA sequence data. We infer the phylogenetic relationships among all 17 extant Phrynosoma species using >5.1 kb of mtDNA (12S rRNA, 16S rRNA, ND1, ND2, ND4, Cyt b, and associated tRNA genes), and >2.2kb from three nuclear genes (RAG-1, BDNF, and GAPD) for most taxa. We conduct separate and combined phylogenetic analyses of these data using maximum parsimony, maximum likelihood, and Bayesian methods. The phylogenetic relationships inferred from the mtDNA data are congruent with previous mtDNA analyses based on fewer characters and provide strong support for most branches. However, we detected strong incongruence between the mtDNA and nuclear data using comparisons of branch support and Shimodaira-Hasegawa tests, with the (P. platyrhinos+P. goodei) clade identified as the primary source of this conflict. Our analysis of a P. mcalliixP. goodei hybrid suggests that this incongruence is caused by reticulation via introgressive hybridization. Our preferred phylogeny based on an analysis of the combined data (excluding the introgressed mtDNA data) provides a new framework for interpreting character evolution and biogeography within Phrynosoma. In the context of this improved phylogeny we propose a phylogenetic taxonomy highlighting four clades: (1) Tapaja, containing the viviparous short-horned lizards P. ditmarsi, P. hernandesi, P. douglasii, and P. orbiculare; (2) Anota, containing species with prominent cranial horns (P. solare, P. mcallii, and the P. coronatum group); (3) Doliosaurus, containing three species lacking antipredator blood-squirting (P. modestum, P. platyrhinos, and P. goodei); and (4) Brevicauda, containing two viviparous species with extremely short tails that lack blood-squirting (P. braconnieri and P. taurus).  相似文献   

14.
全世界记录的长小蠹(鞘翅目:长小蠹科)有1 500余种,其分类地位一直存在争议。本研究通过分子基因信息探讨长小蠹科昆虫的分子系统进化关系,测定了中对长小蠹Euplatypus parallelus(Fabricius)、希氏长小蠹E. hintzi Schaufuss、散对长小蠹E. solutus Schedl、杯长小蠹Dinoplatypus cupulatus Chapuis、小杯长小蠹D. cupulatulus Schedl、芦苇黄截尾长小蠹D. calamus Blandford、五棘长小蠹Diapus quinquespinatus Chapuis、锥长小蠹Treptoplatypus solidus Walk、栎长小蠹Platypus quercivorus Murayama和东亚长小蠹P. lewisi Blandford等长小蠹科5属10种mtDNA COⅠ基因部分序列(549 bp);采用MEGA3.1分析了序列组成及遗传距离,应用PAUP4.0分别构建了长小蠹NJ,MP和ML等3种分子系统树,同时结合长小蠹的形态分类,探讨10 种长小蠹及其所在属的系统进化。结果表明:长小蠹科昆虫在碱基使用频率上有很大的偏向性;长小蠹科与外群小蠹科松瘤小蠹Orthotomicus erosus Wollaston之间的遗传距离(0.288~0.338)远大于科内种间距离(0~0.226);Diapus属分化最早,Euplatypus属独成一支,Treptohlatypus, Dinoplatypus和Platypus 3属分化为一支。长小蠹科分子系统进化研究结果与Wood(1993)新修订的分类系统基本一致,说明长小蠹科的分类系统更趋于合理。  相似文献   

15.
The growing use of molecular systematics in conservation has increased the importance of accurate resolution of taxonomic units and relationships. DNA data relate most directly to genealogies, which need not have perfect relationships with species limits and phylogenies. We used a multilocus gene tree approach to elucidate the relationships between four endangered Central American iguanas. We found support for the proposition that the described species taxa correspond to distinct evolutionary lineages warranting individual protection. We combined gene trees to estimate a phylogeny using Bayesian Estimation of Species Trees (BEST), minimizing deep coalescence, Species Trees from Average Ranks (STAR), and traditional concatenation. The estimate from concatenation conflicted with the other methods, likely owing to the disproportionate effect of mtDNA on concatenated analyses. This illustrates the importance of appropriate treatment of multilocus sequence data in phylogenetics. Our results indicate that these species have gone through recent and rapid speciation, resulting in four closely related narrow-range endemics.  相似文献   

16.
Chalcidoidea (approximately 22,000 described species) is the most ecologically diverse superfamily of parasitic Hymenoptera and plays a major role in the biological control of insect pests. However, phylogenetic relationships both within and between chalcidoid families have been poorly understood, particularly for the large family Pteromalidae and relatives. Forty-two taxa, broadly representing Chalcidoidea but concentrated in the 'pteromalid lineage,' were sequenced for 4620 bp of protein-coding sequence from four nuclear genes for which we present new primers. These are: CAD (1719 bp) DDC (708 bp), enolase (1149 bp), and PEPCK (1044 bp). The combined data set was analyzed using parsimony, maximum likelihood, and Bayesian methods. Statistical significance of the apparent non-monophyly of some taxonomic groups on our trees was evaluated using the approximately unbiased test of Shimodaira [Shimodaira, H. 2002. An approximately unbiased test of phylogenetic tree selection. Syst. Biol. 51(3), 492-508]. In accord with previous studies, we find moderate to strong support for monophyly of Chalcidoidea, a sister-group relationship of Mymaridae to the remainder of Chalcidoidea, and a relatively basal placement of Encarsia (Aphelinidae) within the latter. The 'pteromalid lineage' of families is generally recovered as monophyletic, but the hypothesis of monophyly for Pteromalidae, which appear paraphyletic with respect to all other families sampled in that lineage, is decisively rejected (P < 10(-14)). Within Pteromalidae, monophyly was strongly supported for nearly all tribes represented by multiple exemplars, and for two subfamilies. All other multiply-represented subfamilies appeared para- or polyphyletic in our trees, although monophyly was significantly rejected only for Miscogasterinae, Ormocerinae, and Colotrechninae. The limited resolution obtained in the analyses presented here reinforces the idea that reconstruction of pteromalid phylogeny is a difficult problem, possibly due to rapid radiation of many chalcidoid taxa. Initial phylogenetic comparisons of life history traits suggest that the ancestral chalcidoid was small-bodied and parasitized insect eggs.  相似文献   

17.
18.
The taxonomic treatment within the unigeneric tribe Yinshanieae(Brassicaceae) is controversial, owing to differences in generic delimitation applied to its species. In this study, sequences from nuclear ITS and chloroplast trn L-F regions were used to test the monophyly of Yinshanieae, while two nuclear markers(ITS, ETS) and four chloroplast markers(trnL-F, trn H-psbA, rps16, rpL32-trnL) were used to elucidate the phylogenetic relationships within the tribe. Using maximum parsimony, maximum likelihood, and Bayesian inference methods, we reconstructed the phylogeny of Brassicaceae and Yinshanieae. The results show that Yinshanieae is not a monophyletic group, with the taxa splitting into two distantly related clades: one clade contains four taxa and falls in Lineage I, whereas the other includes all species previously placed in Hilliella and is embedded in the Expanded Lineage II. The tribe Yinshanieae is redefined, and a new tribe, Hillielleae, is proposed based on combined evidence from molecular phylogeny, morphology, and cytology.  相似文献   

19.
The spider mite sub-family Tetranychinae includes many agricultural pests. The internal transcribed spacer (ITS) region of nuclear ribosomal RNA genes and the cytochrome c oxidase subunit I (COI) gene of mitochondrial DNA have been used for species identification and phylogenetic reconstruction within the sub-family Tetranychinae, although they have not always been successful. The 18S and 28S rRNA genes should be more suitable for resolving higher levels of phylogeny, such as tribes or genera of Tetranychinae because these genes evolve more slowly and are made up of conserved regions and divergent domains. Therefore, we used both the 18S (1,825–1,901 bp) and 28S (the 5′ end of 646–743 bp) rRNA genes to infer phylogenetic relationships within the sub-family Tetranychinae with a focus on the tribe Tetranychini. Then, we compared the phylogenetic tree of the 18S and 28S genes with that of the mitochondrial COI gene (618 bp). As observed in previous studies, our phylogeny based on the COI gene was not resolved because of the low bootstrap values for most nodes of the tree. On the other hand, our phylogenetic tree of the 18S and 28S genes revealed several well-supported clades within the sub-family Tetranychinae. The 18S and 28S phylogenetic trees suggest that the tribes Bryobiini, Petrobiini and Eurytetranychini are monophyletic and that the tribe Tetranychini is polyphyletic. At the genus level, six genera for which more than two species were sampled appear to be monophyletic, while four genera (Oligonychus, Tetranychus, Schizotetranychus and Eotetranychus) appear to be polyphyletic. The topology presented here does not fully agree with the current morphology-based taxonomy, so that the diagnostic morphological characters of Tetranychinae need to be reconsidered.  相似文献   

20.
Abstract: Intrageneric relationships in the genus Nicotiana were investigated by comparison of DNA sequences of the matK gene of the chloroplast genome. A total of 40 taxa were examined in this study, representing 39 of the approximately 70 wild species of this genus. We obtained the full sequences of the 1530 bp matK ORFs; no variations in length due to insertions or deletions were found. The phylogenetic trees obtained from maximum parsimony (MP) and neighbour-joining (NJ) methods were fundamentally consistent. The genus Nicotiana formed a clade in these trees. The traditional classification of this genus was mostly in agreement with the molecular phylogeny. However, all three subgenera and some sections did not form a monophyletic group. Character-state mappings were used to infer a centre of origin, biogeographic history, and transition of chromosome number. The results support the previous hypothesis that this genus originated in South America and subsequently spread to other continents. The suggestion that the ancestral basic chromosome number is x = 12 and that polyploidy and aneuploidy have occurred independently several times during the evolution of Nicotiana species is also discussed.  相似文献   

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