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1.
Supermatrix and supertree are two methods for constructing a phylogenetic tree by using multiple data sets. However, these methods are not a panacea, as conflicting signals between data sets can lead to misinterpret the evolutionary history of taxa. In particular, the supermatrix approach is expected to be misleading if the species-tree signal is not dominant after the combination of the data sets. Moreover, most current supertree methods suffer from two limitations: (i) they ignore or misinterpret secondary (non-dominant) phylogenetic signals of the different data sets; and (ii) the logical basis of node robustness measures is unclear.To overcome these limitations, we propose a new approach, called SuperTRI, which is based on the branch support analyses of the independent data sets, and where the reliability of the nodes is assessed using three measures: the supertree Bootstrap percentage and two other values calculated from the separate analyses: the mean branch support (mean Bootstrap percentage or mean posterior probability) and the reproducibility index.The SuperTRI approach is tested on a data matrix including seven genes for 82 taxa of the family Bovidae (Mammalia, Ruminantia), and the results are compared to those found with the supermatrix approach. The phylogenetic analyses of the supermatrix and independent data sets were done using four methods of tree reconstruction: Bayesian inference, maximum likelihood, and unweighted and weighted maximum parsimony. The results indicate, firstly, that the SuperTRI approach shows less sensitivity to the four phylogenetic methods, secondly, that it is more accurate to interpret the relationships among taxa, and thirdly, that interesting conclusions on introgression and radiation can be drawn from the comparisons between SuperTRI and supermatrix analyses. To cite this article: A. Ropiquet et al., C. R. Biologies 332 (2009).  相似文献   

2.

Background  

Supertree methods comprise one approach to reconstructing large molecular phylogenies given multi-marker datasets: trees are estimated on each marker and then combined into a tree (the "supertree") on the entire set of taxa. Supertrees can be constructed using various algorithmic techniques, with the most common being matrix representation with parsimony (MRP). When the data allow, the competing approach is a combined analysis (also known as a "supermatrix" or "total evidence" approach) whereby the different sequence data matrices for each of the different subsets of taxa are concatenated into a single supermatrix, and a tree is estimated on that supermatrix.  相似文献   

3.
Many research groups are estimating trees containing anywhere from a few thousands to hundreds of thousands of species, toward the eventual goal of the estimation of a Tree of Life, containing perhaps as many as several million leaves. These phylogenetic estimations present enormous computational challenges, and current computational methods are likely to fail to run even on data sets in the low end of this range. One approach to estimate a large species tree is to use phylogenetic estimation methods (such as maximum likelihood) on a supermatrix produced by concatenating multiple sequence alignments for a collection of markers; however, the most accurate of these phylogenetic estimation methods are extremely computationally intensive for data sets with more than a few thousand sequences. Supertree methods, which assemble phylogenetic trees from a collection of trees on subsets of the taxa, are important tools for phylogeny estimation where phylogenetic analyses based upon maximum likelihood (ML) are infeasible. In this paper, we introduce SuperFine, a meta-method that utilizes a novel two-step procedure in order to improve the accuracy and scalability of supertree methods. Our study, using both simulated and empirical data, shows that SuperFine-boosted supertree methods produce more accurate trees than standard supertree methods, and run quickly on very large data sets with thousands of sequences. Furthermore, SuperFine-boosted matrix representation with parsimony (MRP, the most well-known supertree method) approaches the accuracy of ML methods on supermatrix data sets under realistic conditions.  相似文献   

4.
Phylogenetic relationships of 79 caniform carnivores were addressed based on four nuclear sequence-tagged sites (STS) and one nuclear exon, IRBP, using both supertree and supermatrix analyses. We recovered the three major arctoid lineages, Ursidae, Pinnipedia, and Musteloidea, as monophyletic, with Ursidae (bears) strongly supported as the basal arctoid lineage. Within Pinnipedia, Phocidae (true seals) were sister to the Otaroidea [Otariidae (fur seals and sea lions) and Odobenidae (walrus)]. Phocid subfamily and tribal designations were supported, but the otariid subfamily split between fur seals and sea lions was not. All family designations within Musteloidea were strongly supported: Mephitidae (skunks), Ailuridae (monotypic red panda), Mustelidae (weasels, badgers, otters), and Procyonidae (raccoons). A novel hypothesis for the position of the red panda was recovered, placing it as branching after Mephitidae and before Mustelidae+Procyonidae. Within Mustelidae, subfamily taxonomic changes are considered. This study represents the most comprehensive sampling to date of the Caniformia in a molecular study and contains the most complete molecular phylogeny for the Procyonidae. Our data set was also used in an empirical examination of the effect of missing data on both supertree and supermatrix analyses. Sequence for all genes in all taxa could not be obtained, so two variants of the data set with differing amounts of missing data were examined. The amount of missing data did not have a strong effect; instead, phylogenetic resolution was more dependent on the presence of sufficient informative characters. Supertree and supermatrix methods performed equivalently with incomplete data and were highly congruent; conflicts arose only in weakly supported areas, indicating that more informative characters are required to confidently resolve close species relationships.  相似文献   

5.
Ren F  Tanaka H  Yang Z 《Gene》2009,441(1-2):119-125
Supermatrix and supertree methods are two strategies advocated for phylogenetic analysis of sequence data from multiple gene loci, especially when some species are missing at some loci. The supermatrix method concatenates sequences from multiple genes into a data supermatrix for phylogenetic analysis, and ignores differences in evolutionary dynamics among the genes. The supertree method analyzes each gene separately and assembles the subtrees estimated from individual genes into a supertree for all species. Most algorithms suggested for supertree construction lack statistical justifications and ignore uncertainties in the subtrees. Instead of supermatrix or supertree, we advocate the use of likelihood function to combine data from multiple genes while accommodating their differences in the evolutionary process. This combines the strengths of the supermatrix and supertree methods while avoiding their drawbacks. We conduct computer simulation to evaluate the performance of the supermatrix, supertree, and maximum likelihood methods applied to two phylogenetic problems: molecular-clock dating of species divergences and reconstruction of species phylogenies. The results confirm the theoretical superiority of the likelihood method. Supertree or separate analyses of data of multiple genes may be useful in revealing the characteristics of the evolutionary process of multiple gene loci, and the information may be used to formulate realistic models for combined analysis of all genes by likelihood.  相似文献   

6.
Nonparamtric bootstrapping methods may be useful for assessing confidence in a supertree inference. We examined the performance of two supertree bootstrapping methods on four published data sets that each include sequence data from more than 100 genes. In "input tree bootstrapping," input gene trees are sampled with replacement and then combined in replicate supertree analyses; in "stratified bootstrapping," trees from each gene's separate (conventional) bootstrap tree set are sampled randomly with replacement and then combined. Generally, support values from both supertree bootstrap methods were similar or slightly lower than corresponding bootstrap values from a total evidence, or supermatrix, analysis. Yet, supertree bootstrap support also exceeded supermatrix bootstrap support for a number of clades. There was little overall difference in support scores between the input tree and stratified bootstrapping methods. Results from supertree bootstrapping methods, when compared to results from corresponding supermatrix bootstrapping, may provide insights into patterns of variation among genes in genome-scale data sets.  相似文献   

7.
For the last 2 decades, supertree reconstruction has been an active field of research and has seen the development of a large number of major algorithms. Because of the growing popularity of the supertree methods, it has become necessary to evaluate the performance of these algorithms to determine which are the best options (especially with regard to the supermatrix approach that is widely used). In this study, seven of the most commonly used supertree methods are investigated by using a large empirical data set (in terms of number of taxa and molecular markers) from the worldwide flowering plant family Sapindaceae. Supertree methods were evaluated using several criteria: similarity of the supertrees with the input trees, similarity between the supertrees and the total evidence tree, level of resolution of the supertree and computational time required by the algorithm. Additional analyses were also conducted on a reduced data set to test if the performance levels were affected by the heuristic searches rather than the algorithms themselves. Based on our results, two main groups of supertree methods were identified: on one hand, the matrix representation with parsimony (MRP), MinFlip, and MinCut methods performed well according to our criteria, whereas the average consensus, split fit, and most similar supertree methods showed a poorer performance or at least did not behave the same way as the total evidence tree. Results for the super distance matrix, that is, the most recent approach tested here, were promising with at least one derived method performing as well as MRP, MinFlip, and MinCut. The output of each method was only slightly improved when applied to the reduced data set, suggesting a correct behavior of the heuristic searches and a relatively low sensitivity of the algorithms to data set sizes and missing data. Results also showed that the MRP analyses could reach a high level of quality even when using a simple heuristic search strategy, with the exception of MRP with Purvis coding scheme and reversible parsimony. The future of supertrees lies in the implementation of a standardized heuristic search for all methods and the increase in computing power to handle large data sets. The latter would prove to be particularly useful for promising approaches such as the maximum quartet fit method that yet requires substantial computing power.  相似文献   

8.
It has been proposed that supertree approaches should be applied to large multilocus datasets to achieve computational tractability. Large datasets such as those derived from phylogenomics studies can be broken into many locus‐specific tree searches and the resulting trees can be stitched together via a supertree method. Using simulated data, workers have reported that they can rapidly construct a supertree that is comparable to the results of heuristic tree search on the entire dataset. To test this assertion with organismal data, we compare tree length under the parsimony criterion and computational time for 20 multilocus datasets using supertree (SuperFine and SuperTriplets) and supermatrix (heuristic search in TNT) approaches. Tree length and computational times were compared among methods using the Wilcoxon matched‐pairs signed rank test. Supermatrix searches produced significantly shorter trees than either supertree approach (SuperFine or SuperTriplets; P < 0.0002 in both cases). Moreover, the processing time of supermatrix search was significantly lower than SuperFine+locus‐specific search (P < 0.01) but roughly equivalent to that of SuperTriplets+locus‐specific search (P > 0.4, not significant). In conclusion, we show by using real rather than simulated data that there is no basis, either in time tractability or in tree length, for use of supertrees over heuristic tree search using a supermatrix for phylogenomics.  相似文献   

9.
The Lecanoromycetes includes most of the lichen-forming fungal species (> 13500) and is therefore one of the most diverse class of all Fungi in terms of phenotypic complexity. We report phylogenetic relationships within the Lecanoromycetes resulting from Bayesian and maximum likelihood analyses with complementary posterior probabilities and bootstrap support values based on three combined multilocus datasets using a supermatrix approach. Nine of 10 orders and 43 of 64 families currently recognized in Eriksson's classification of the Lecanoromycetes (Outline of Ascomycota--2006 Myconet 12:1-82) were represented in this sampling. Our analyses strongly support the Acarosporomycetidae and Ostropomycetidae as monophyletic, whereas the delimitation of the largest subclass, the Lecanoromycetidae, remains uncertain. Independent of future delimitation of the Lecanoromycetidae, the Rhizocarpaceae and Umbilicariaceae should be elevated to the ordinal level. This study shows that recent classifications include several nonmonophyletic taxa at different ranks that need to be recircumscribed. Our phylogenies confirm that ascus morphology cannot be applied consistently to shape the classification of lichen-forming fungi. The increasing amount of missing data associated with the progressive addition of taxa resulted in some cases in the expected loss of support, but we also observed an improvement in statistical support for many internodes. We conclude that a phylogenetic synthesis for a chosen taxonomic group should include a comprehensive assessment of phylogenetic confidence based on multiple estimates using different methods and on a progressive taxon sampling with an increasing number of taxa, even if it involves an increasing amount of missing data.  相似文献   

10.
The up-dated species level phylogeny for the carnivores using a supertree approach provides new insights into the evolutionary origin and relationships of carnivores. While the gain in biological knowledge is substantial, the supertree approach is not undisputed. I discuss the principles of supertree methods and the competitor supermatrix approaches. I argue that both methods are important to infer phylogenetic relationships.  相似文献   

11.
The resolution of the phylogenetic relationships within the order Teloschistales (Ascomycota, lichen-forming-fungi), with nearly 2000 known species and outstanding phenotypic diversity, has been hindered by the limitation in the resolving power that single-locus or two-locus phylogenetic studies have provided to date. In this context, an extensive taxon sampling within the Teloschistales with more loci (especially nuclear protein-coding genes) was needed to confront the current taxonomic delimitations and to understand evolutionary trends within this order. Comprehensive maximum likelihood and bayesian analyses were performed based on seven loci using a cumulative supermatrix approach, including protein-coding genes RPB1 and RPB2 in addition to nuclear and mitochondrial ribosomal RNA-coding genes. We included 167 taxa representing 12 of the 15 genera recognized within the currently accepted Teloschistineae, 22 of the 43 genera within the Physciineae, 49 genera of the closely related orders Lecanorales, Lecideales, and Peltigerales, and the dubiously placed family Brigantiaeaceae and genus Sipmaniella. Although the progressive addition of taxa (cumulative supermatrix approach) with increasing amounts of missing data did not dramatically affect the loss of support and resolution, the monophyly of the Teloschistales in the current sense was inconsistent, depending on the loci-taxa combination analyzed. Therefore, we propose a new, but provisional, classification for the re-circumscribed orders Caliciales and Teloschistales (previously referred to as Physciineae and Teloschistineae, respectively). We report here that the family Brigantiaeaceae, previously regarded as incertae sedis within the subclass Lecanoromycetidae, and Sipmaniella, are members of the Teloschistales in a strict sense. Within this order, one lineage led to the diversification of the mostly epiphytic crustose Brigantiaeaceae and Letrouitiaceae, with a circumpacific center of diversity and found mostly in the tropics. The other main lineage led to another epiphytic crustose family, mostly tropical, and with an Australasian center of diversity--the Megalosporaceae--which is sister to the mainly rock-inhabiting, cosmopolitan, and species rich Teloschistaceae, with a diversity of growth habits ranging from crustose to fruticose. Our results confirm the use of a cumulative supermatrix approach as a viable method to generate comprehensive phylogenies summarizing relationships of taxa with multi-locus to single locus data.  相似文献   

12.
The problem of missing data is often considered to be the most important obstacle in reconstructing the phylogeny of fossil taxa and in combining data from diverse characters and taxa for phylogenetic analysis. Empirical and theoretical studies show that including highly incomplete taxa can lead to multiple equally parsimonious trees, poorly resolved consensus trees, and decreased phylogenetic accuracy. However, the mechanisms that cause incomplete taxa to be problematic have remained unclear. It has been widely assumed that incomplete taxa are problematic because of the proportion or amount of missing data that they bear. In this study, I use simulations to show that the reduced accuracy associated with including incomplete taxa is caused by these taxa bearing too few complete characters rather than too many missing data cells. This seemingly subtle distinction has a number of important implications. First, the so-called missing data problem for incomplete taxa is, paradoxically, not directly related to their amount or proportion of missing data. Thus, the level of completeness alone should not guide the exclusion of taxa (contrary to common practice), and these results may explain why empirical studies have sometimes found little relationship between the completeness of a taxon and its impact on an analysis. These results also (1) suggest a more effective strategy for dealing with incomplete taxa, (2) call into question a justification of the controversial phylogenetic supertree approach, and (3) show the potential for the accurate phylogenetic placement of highly incomplete taxa, both when combining diverse data sets and when analyzing relationships of fossil taxa.  相似文献   

13.
Recent reviews of the construction of large phylogenies have focused on supertree methods that involve separate analyses of data sets and subsequent integration of the resulting trees. Here, we consider the alternative method of analyzing all character data simultaneously. Such 'supermatrix' analyses use information from each character directly and enable straightforward incorporation of diverse kinds of data, including characters from fossils. The approach has been extended by the development of new methods, including model-based techniques for analyzing heterogeneous data and hierarchical methods for constructing extremely large trees. Recent work also suggests that the problem of missing data in supermatrix analyses has been overstated. Although the supermatrix approach is not suited for all cases, we suggest that its inherent strengths will ensure that it will continue to have a central role in inferring large phylogenetic trees from diverse data.  相似文献   

14.
Inferring the evolutionary history of a group of species can be challenging given the many factors involved. In recent years, the increased availability of sequences of multiple genes per species has spurred the development of new methodologies to analyse multilocus data sets. Two approaches that analyse such data are concatenated supermatrix and coalescent-based species-tree analyses. In this study, we used both of these methods to infer the phylogenetic relationships of Iberian species of the genus Squalius from one mitochondrial and six nuclear genes. We found mitonuclear discordance in the phylogenetic relationships of the group. According to the mitochondrial gene analysis, all species were recovered as monophyletic except S. pyrenaicus; besides, in the concatenated supermatrix analysis of the nuclear markers, this species resolved as polyphyletic with three divergent evolutionary lineages. The coalescent-based nuclear species-tree analysis rendered a well-resolved phylogeny compared with the supermatrix analysis, which was unable to discern between S. carolitertii, S. castellanus and one of the evolutionary lineages of S. pyrenaicus. This result is likely due to the better integration of population uncertainty in the coalescent approach. Furthermore, Bayesian multilocus species delimitation analyses based on a BPP approach strongly supported the distinct nuclear lineages as different species. Nevertheless, the supermatrix analysis was able to obtain well-supported relationships in the divergent lineages with low numbers of individuals. Our study highlights the usefulness of different analytical methodologies to obtain a more complete picture of the evolutionary history of taxa, especially when discordant patterns among genes are found.  相似文献   

15.
This study has as its primary aim the robust resolution of higher‐level relationships within the lepidopteran superfamily Bombycoidea. Our study builds on an earlier analysis of five genes (~6.6 kbp) sequenced for 50 taxa from Bombycoidea and its sister group Lasiocampidae, plus representatives of other macrolepidoteran superfamilies. The earlier study failed to yield strong support for the monophyly of and basal splits within Bombycoidea, among others. Therefore, in an effort to increase support specifically for higher‐level nodes, we generated 11.7 kbp of additional data from 20 genes for 24 of 50 bombycoid and lasiocampid taxa. The data from the genes are all derived from protein‐coding nuclear genes previously used to resolve other lepidopteran relationships. With these additional data, all but a few higher‐level nodes are strongly supported. Given our decision to minimize project costs by augmenting genes for only 24 of the 50 taxa, we explored whether the resulting pattern of missing data in the combined‐gene matrix introduced a nonphylogenetic bias, a possibility reported by others. This was achieved by comparing node support values (i.e. nonparametric bootstrap values) based on likelihood and parsimony analyses of three datasets that differ in their number of taxa and level of missing data: 50 taxa/5 genes (dataset A), 50 taxa/25 genes (dataset B) and 24 taxa/25 genes (dataset C). Whereas datasets B and C provided similar results for common nodes, both frequently yielded higher node support relative to dataset A, arguing that: (i) more data yield increased node support and (ii) partial gene augmentation does not introduce an obvious nonphylogenetic bias. A comparison of single‐gene bootstrap analyses identified four nodes for which one or two of the 25 genes provided modest to strong support for a grouping not recovered by the combined‐gene result. As a summary proposal, two of these four groupings (one each within Bombycoidea and Lasiocampidae) were deemed sufficiently problematic to regard them as unresolved trichotomies. Since the alternative groupings were always highly localized on the tree, we did not judge a combined‐gene analysis to present a problem outside those regions. Based on our robustly resolved results, we have revised the classification of Bombycoidea: the family Bombycidae is restricted to its nominate subfamily, and its tribe Epiini is elevated to subfamily rank (Epiinae stat.rev. ), whereas the bombycid subfamily Phiditiinae is reinstated as a separate family (Phiditiidae stat.rev. ). The bombycid subfamilies Oberthueriinae Kuznetzov & Stekolnikov, 1985, syn.nov. and Prismostictinae Forbes, 1955, syn.nov. , and the family Mirinidae Kozlov, 1985, syn.nov. are established as subjective junior synonyms of Endromidae Boisduval, 1828. The family Anthelidae (Lasiocampoidea) is reincluded in the superfamily Bombycoidea.  相似文献   

16.
Kozak et al. (2015, Syst. Biol., 64: 505) portrayed the inference of evolutionary history among Heliconius and allied butterfly genera as a particularly difficult problem for systematics due to prevalent gene conflict caused by interspecific reticulation. To control for this, Kozak et al. conducted a series of multispecies coalescent phylogenetic analyses that they claimed revealed pervasive conflict among markers, but ultimately chose as their preferred hypothesis a phylogenetic tree generated by the traditional supermatrix approach. Intrigued by this seemingly contradictory set of conclusions, we conducted further analyses focusing on two prevalent aspects of the data set: missing data and the uneven contribution of phylogenetic signal among markers. Here, we demonstrate that Kozak et al. overstated their findings of reticulation and that evidence of gene‐tree conflict is largely lacking. The distribution of intrinsic homoplasy and incongruence homoplasy in their data set does not follow the pattern expected if phylogenetic history had been obscured by pervasive horizontal gene flow; in fact, noise within individual gene partitions is ten times higher than the incongruence among gene partitions. We show that the patterns explained by Kozak et al. as a result of reticulation can be accounted for by missing data and homoplasy. We also find that although the preferred topology is resilient to missing data, measures of support are sensitive to, and strongly eroded by too many empty cells in the data matrix. Perhaps more importantly, we show that when some taxa are missing almost all characters, adding more genes to the data set provides little or no increase in support for the tree.  相似文献   

17.
18.
吴良  宋明华  欧阳华 《遗传》2009,31(7):689-697
DNA序列、形态和其他同源性状可以用于推断物种的起源和历史。整合所有可利用的系统发育信息可以大大拓展所覆盖类群的范围, 推进我们对现存生物的认识, 而且使得生物学家提出和验证的假说尺度更广, 更有统计说服力。文章综述了整合系统发育信息的概念及其与传统分析的异同, 重点讨论了整合系统发育信息中应用最广的超级树(Supertree)和超级矩阵(Supermatrix)方法; 在比较分析了这两个方法的优缺点之后, 介绍了近些年提出的新的方法。文章详细分析了整合系统发育信息的发展所面临的来自数据和理论方面的挑战, 认为尽管整合分析的发展困难较多, 它仍然是到目前为止构建完整生命之树(网)的唯一方法; 它的完善必将拓展我们对于生物进化过程的认识, 并对进化生物学相关学科产生积极影响。  相似文献   

19.
The phylogenetic relationships between western Palaearctic Zamenis and Rhinechis ratsnakes have been troubled, with recent estimates based on the supermatrix approach questioning their monophyly and providing contradictory results. In this study, we generated a comprehensive molecular data set for Zamenis and closely related ratsnakes to assess their phylogenetic and systematic relationships and infer their spatial and temporal modes of diversification. We obtained a fully resolved and well‐supported phylogeny, which is consistent across markers, taxon‐sets and phylogenetic methods. The close phylogenetic relationship between Rhinechis and Zamenis is well‐established. However, the early branching pattern within this clade, and the position of R. scalaris and Z. hohenackeri, remains poorly supported. The Persian ratsnake Z. persicus is sister to the Mediterranean species Z. situla, Z. longissimus and Z. lineatus, of which Z. situla is sister to a clade containing the latter two species. These results are consistent with a recent phylogenomic study on ratsnakes based on hundreds of loci. Whereas, topological tests based on our data and evidence from such phylogenomic study strongly rejected previous phylogenetic estimates based on the supermatrix approach and demonstrate that these “mega‐phylogenies”, with hundreds of taxa and high levels of missing data, have recovered inconsistent relationships with spurious nodal support. Biogeographical and molecular dating analyses suggest an origin of the ancestor of Rhinechis and Zamenis in the Aegean region with early cladogenesis during the Late Miocene associated with the Aegean arch formation and support a scenario of east‐to‐west diversification. Finally, while we have little morphological and phylogenetic evidence for the distinctiveness between Rhinechis and Zamenis, a classification of them in a single genus, and the designation of Zamenis scalaris (Schinz, 1822), reflects better their evolutionary relationships.  相似文献   

20.
Pe?nerová, P. & Martínková, N. (2012). Evolutionary history of tree squirrels (Rodentia, Sciurini) based on multilocus phylogeny reconstruction. —Zoologica Scripta, 41, 211–219. Tree squirrels of the tribe Sciurini represent a group with unresolved phylogenetic relationships in gene trees. We used partial sequences of mitochondrial genes for 12S rRNA, 16S rRNA, cytochrome b and d‐loop, and nuclear irbp, c‐myc exon 2 and 3 and rag1 genes to reconstruct phylogenetic relationships within the tribe, maximizing the number of analysed species. Bayesian inference analysis of the concatenated sequences revealed common trends that were similar to those retrieved with supertree reconstruction. We confirmed congruence between phylogeny and zoogeography. The first group that diverged from a common ancestor was genus Tamiasciurus, followed by Palaearctic Sciurus and Indomalayan Rheithrosciurus macrotis. Nearctic and Neotropical Sciurus species formed a monophyletic group that included Microsciurus and Syntheosciurus. Neotropical Sciurini were monophyletic with a putative exception of Syntheosciurus brochus that was included in a polychotomy with Nearctic Sciurus in supertree analyses. Our data indicate that Sciurini tree squirrels originated in the northern hemisphere and ancestors of contemporary taxa attained their current distribution through overland colonization from the nearest continent rather than through trans‐Pacific dispersal.  相似文献   

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