Molecular Phylogeny of the Genus Paramesotriton (Caudata: Salamandridae)

To elucidate the phylogeny of the genus Paramesotriton (Caudata: Salamandridae), we investigated three mitochondrial DNA gene fragments (1207 bp in total) of cytochrome b, ND2, and ND4 for its six recognized species. The phylogenetic relationships within Paramesotriton were reconstructed by maximum parsimony (MP) and maximum likelihood (ML) methods. Phylogenetic trees (MP and ML trees) that were constructed from the combined data set of the three gene fragments indicated that all six species of Paramesotriton formed a monophyletic group, with P. caudopunctatus as basal to the other five species. This result suggests that P. fuzhongensis is a valid species in Paramesotriton.     

Phylogenetic analysis of the mitochondrial cytochrome oxidase subunit I gene of five species of the Culicoides imicola species complex

The phylogenetic status of members of the Culicoides imicola Kieffer (Diptera: Ceratopogonidae) species complex of haematophagous midges is unknown, and simple means to identify the members using all life stages are unavailable. In this study, the status of three confirmed (C. imicola s.s., C. bolitinos Meiswinkel and C. loxodontis Meiswinkel) and two provisional (C. tuttifrutti Meiswinkel and C. kwagga Meiswinkel) members of the complex from South Africa was assessed using phylogenetic analysis of partial DNA and amino acid sequences of the mitochondrial cytochrome oxidase subunit I (COI) gene. The four or five individuals of each species analysed contained one or two haplotypes each. Interspecific divergence was significant and characterized by strong A <--> T transversion bias. Phylogenetic trees constructed using neighbour-joining, parsimony and maximum likelihood showed each species to be distinct. Combinations of sites for two restriction enzymes in the COI sequences were species-specific and could form the basis of a diagnostic PCR assay.     

On the best evolutionary rate for phylogenetic analysis

The effect of the evolutionary rate of a gene on the accuracy of phylogeny reconstruction was examined by computer stimulation. The evolutionary rate is measured by the tree length, that is, the expected total number of nucleotide substitutions per site on the phylogeny. DNA sequence data were simulated using both fixed trees with specified branch lengths and random trees with branch lengths generated from a model of cladogenesis. The parsimony and likelihood methods were used for phylogeny reconstruction, and the proportion of correctly recovered branch partitions by each method was estimated. Phylogenetic methods including parsimony appear quite tolerant of multiple substitutions at the same site. The optimum levels of sequence divergence were even higher than upper limits previously suggested for saturation of substitutions, indicating that the problem of saturation may have been exaggerated. Instead, the lack of information at low levels of divergence should be seriously considered in evaluation of a gene's phylogenetic utility, especially when the gene sequence is short. The performance of parsimony, relative to that of likelihood, does not necessarily decrease with the increase of the evolutionary rate.     

An early origin of plastids within the cyanobacterial divergence is suggested by evolutionary trees based on complete 16S rRNA sequences

It is generally accepted that the plastids arose from a cyanobacterial ancestor, but the exact phylogenetic relationships between cyanobacteria and plastids are still controversial. Most studies based on partial 16S rRNA sequences suggested a relatively late origin of plastids within the cyanobacterial divergence. In order to clarify the exact relationship and divergence order of cyanobacteria and plastids, we studied their phylogeny on the basis of nearly complete 16S rRNA gene sequences. The data set comprised 15 strains of cyanobacteria from different morphological groups, 1 prochlorophyte, and plastids belonging to 8 species of plants and 12 species of diverse algae. This set included three cyanobacterial sequences determined in this study. This is the most comprehensive set of complete cyanobacterial and plastidial 16S rRNA sequences used so far. Phylogenetic trees were constructed using neighbor joining and maximum parsimony, and the reliability of the tree topologies was tested by different methods. Our results suggest an early origin of plastids within the cyanobacterial divergence, preceded only by the divergence of two cyanobacterial genera, Gloeobacter and Pseudanabaena.      

Utility of the white gene in estimating phylogenetic relationships among mosquitoes (Diptera: Culicidae)

The utility of a nuclear protein-coding gene for reconstructing phylogenetic relationships within the family Culicidae was explored. Relationships among 13 species representing three subfamilies and nine genera of Culicidae were analyzed using a 762-bp fragment of coding sequence from the eye color gene, white. Outgroups for the study were two species from the sister group Chaoboridae. Sequences were determined from clone PCR products amplified from genomic DNA, and aligned following conceptual intron splicing and amino acid translation. Third codon positions were characterized by high levels of divergence and biased nucleotide composition, the intensity and direction of which varied among taxa. Equal weighting of all characters resulted in parsimony and neighboring-joining trees at odds with the generally accepted phylogenetic hypothesis based on morphology and rDNA sequences. The application of differential weighting schemes recovered the traditional hypothesis, in which the subfamily Anophelinae formed the basal clade. The subfamily Toxorhynchitinae occupied an intermediate position, and was a sister group to the subfamily Culicinae. Within Culicinae, the genera Sabethes and Tripteroides formed an ancestral clade, while the Culex-Deinocerites and Aedes- Haemagogus clades occupied increasingly derived positions in the molecular phylogeny. An intron present in the Culicinae- Toxorhynchitinae lineage and one outgroup taxon was absent in the basal Anophelinae lineage and the second outgroup taxon, suggesting that intron insertions or deletions may not always be reliable systematic characters.      

The phylogenetic significance of peptidoglycan types: Molecular analysis of the genera Microbacterium and Aureobacterium based upon sequence comparison of gyrB, rpoB, recA and ppk and 16SrRNA genes

The type strains of 27 species of the genus Microbacterium, family Microbacteriaceae, were analyzed with respect to the phylogeny of the housekeeping genes coding for DNA gyrase subunit B (gyrB), RNA-polymerase subunit B (rpoB), recombinase A (recA) and polyphosphate kinase (ppk). The resulting gene trees were compared to the 16S rRNA gene phylogeny of the same species. The topology of neighbour-joining and maximum parsimony phylogenetic trees based upon nucleic acid sequences and protein sequences of housekeeping genes differed among each other and no gene tree was identical to that of the 16S rRNA gene tree. Only some species showed consistent clustering by all genes analyzed, but the majority of species branched with different neighbours in most gene trees. The failure to phylogenetically cluster type strains into two groups based upon differences in the amino acid composition of peptidoglycan on the basis of 16S rRNA gene sequence similarity, once leading to the union of the genera Microbacterium and Aureobacterium, was also seen in the analysis of recA, rpoB and gyrB gene and protein phylogenies. Analysis of the pkk gene and protein as well as of a concatenate tree, combining sequences of all five genes (total of 3.700 nucleotides), sees members of the former genus Aureobacterium and other type strains with lysine as diagnostic diamino acid to form a coherent cluster that branches within the radiation of Microbacterium species with ornithine in the peptidoglycan.     

Mitochondrial DNA,morphology, and the phylogenetic relationships of Antarctic icefishes (Notothenioidei: Channichthyidae)

The Channichthyidae is a lineage of 16 species in the Notothenioidei, a clade of fishes that dominate Antarctic near-shore marine ecosystems with respect to both diversity and biomass. Among four published studies investigating channichthyid phylogeny, no two have produced the same tree topology, and no published study has investigated the degree of phylogenetic incongruence between existing molecular and morphological datasets. In this investigation we present an analysis of channichthyid phylogeny using complete gene sequences from two mitochondrial genes (ND2 and 16S) sampled from all recognized species in the clade. In addition, we have scored all 58 unique morphological characters used in three previous analyses of channichthyid phylogenetic relationships. Data partitions were analyzed separately to assess the amount of phylogenetic resolution provided by each dataset, and phylogenetic incongruence among data partitions was investigated using incongruence length difference (ILD) tests. We utilized a parsimony-based version of the Shimodaira-Hasegawa test to determine if alternative tree topologies are significantly different from trees resulting from maximum parsimony analysis of the combined partition dataset. Our results demonstrate that the greatest phylogenetic resolution is achieved when all molecular and morphological data partitions are combined into a single maximum parsimony analysis. Also, marginal to insignificant incongruence was detected among data partitions using the ILD. Maximum parsimony analysis of all data partitions combined results in a single tree, and is a unique hypothesis of phylogenetic relationships in the Channichthyidae. In particular, this hypothesis resolves the phylogenetic relationships of at least two species (Channichthys rhinoceratus and Chaenocephalus aceratus), for which there was no consensus among the previous phylogenetic hypotheses. The combined data partition dataset provides substantial statistical power to discriminate among alternative hypotheses of channichthyid relationships. These findings suggest the optimal strategy for investigating the phylogenetic relationships of channichthyids is one that uses all available phylogenetic data in analyses of combined data partitions.     

ALLOZYME DIVERGENCE WITHIN THE BOVIDAE

We describe a phylogeny of the Bovidae based on 40 allozyme loci in 27 species, representing 10 of the 14 bovid tribes described by Vrba (1985). Giraffe represented a related family (Giraffidae). A phenogram was derived using the unweighted pair-group method with arithmetic means (UPGMA), based on Nei's genetic distances (ND) between species. A tree was also derived using the neighbor-joining technique, also based on ND. To provide a cladistic interpretation, the data were analyzed by a maximum parsimony method (phylogenetic analysis using parsimony, PAUP). We found marked divergence within the Bovidae, consistent with the appearance of the family in the early Miocene. Unexpectedly, the most divergent species was the impala, which occupied a basal position in all trees. Species in the tribe Alcelaphini were the most derived taxa in all trees. These patterns conflict strongly with the previous taxonomic alliance, based on immuno-distance and anatomical evidence, of the impala as a sister group of the Alcelaphini. All trees agreed that tribes described by Vrba (1985) are monophyletic, except the Neotragini, which was polyphyletic, with suni occupying a long branch by itself. The dikdik and klipspringer were consistently placed as sister taxa to species in the Antilopini. Three tribes (Aepycerotini, Tragelaphini and Cephalophini), whose fossils have not been found outside Africa, were basal in all trees, suggesting that bovids originated in Africa. Nodes connecting the remaining tribes were closely clustered, a pattern that agrees with fossil evidence of rapid divergence within the Bovidae in the mid-Miocene (about 15 mybp). The allozyme data suggested a second phase of rapid divergence within tribes during the Plio-Pleistocene, a pattern that also agrees with fossil evidence. Rates of bovid divergence have therefore been far from constant. However, the clustering of nodes imparts considerable uncertainty to the branching order leading to the derived tribes, and to a lesser extent, species within tribes. The classical division of the Bovidae into the Boodontia and Aegeodontia does not agree with the phylogenetic grouping of tribes presented in this analysis. However, the maximum parsimony tree derived using ‘local’ branch swapping clustered all grazing species into a derived, monophyletic group, suggesting that grazing may have evolved only once in bovid evolution.     

Phylogenetic relationships among Phytophthora species inferred from sequence analysis of mitochondrially encoded cytochrome oxidase I and II genes

The phylogenetic relationships of 51 isolates representing 27 species of Phytophthora were assessed by sequence alignment of 568 bp of the mitochondrially encoded cytochrome oxidase II gene. A total of 1299 bp of the cytochrome oxidase I gene also were examined for a subset of 13 species. The cox II gene trees constructed by a heuristic search, based on maximum parsimony for a bootstrap 50% majority-rule consensus tree, revealed 18 species grouping into seven clades and nine species unaffiliated with a specific clade. The phylogenetic relationships among species observed on cox II gene trees did not exhibit consistent similarities in groupings for morphology, pathogenicity, host range or temperature optima. The topology of cox I gene trees, constructed by a heuristic search based on maximum parsimony for a bootstrap 50% majority-rule consensus tree for 13 species of Phytophthora, revealed 10 species grouping into three clades and three species unaffiliated with a specific clade. The groupings in general agreed with what was observed in the cox II tree. Species relationships observed for the cox II gene tree were in agreement with those based on ITS regions, with several notable exceptions. Some of these differences were noted in species in which the same isolates were used for both ITS and cox II analysis, suggesting either a differential rate of evolutionary divergence for these two regions or incorrect assumptions about alignment of ITS sequences. Analysis of combined data sets of ITS and cox II sequences generated a tree that did not differ substantially from analysis of ITS data alone, however, the results of a partition homogeneity test suggest that combining data sets may not be valid.     

Substitution bias, rapid saturation, and the use of mtDNA for nematode systematics

Only relatively recently have researchers turned to molecular methods for nematode phylogeny reconstruction. Thus, we lack the extensive literature on evolutionary patterns and phylogenetic usefulness of different DNA regions for nematodes that exists for other taxa. Here, we examine the usefulness of mtDNA for nematode phylogeny reconstruction and provide data that can be used for a priori character weighting or for parameter specification in models of sequence evolution. We estimated the substitution pattern for the mitochondrial ND4 gene from intraspecific comparisons in four species of parasitic nematodes from the family Trichostrongylidae (38-50 sequences per species). The resulting pattern suggests a strong mutational bias toward A and T, and a lower transition/transversion ratio than is typically observed in other taxa. We also present information on the relative rates of substitution at first, second, and third codon positions and on relative rates of saturation of different types of substitutions in comparisons ranging from intraspecific to interordinal. Silent sites saturate extremely quickly, presumably owing to the substitution bias and, perhaps, to an accelerated mutation rate. Results emphasize the importance of using only the most closely related sequences in order to infer patterns of substitution accurately for nematodes or for other taxa having strongly composition-biased DNA. ND4 also shows high amino acid polymorphism at both the intra- and interspecific levels, and in higher level comparisons, there is evidence of saturation at variable amino acid sites. In general, we recommend using mtDNA coding genes only for phylogenetics of relatively closely related nematode species and, even then, using only nonsynonymous substitutions and the more conserved mitochondrial genes (e.g., cytochrome oxidases). On the other hand, the high substitution rate in genes such as ND4 should make them excellent for population genetics studies, identifying cryptic species, and resolving relationships among closely related congeners when other markers show insufficient variation.      

A comparison of cytochrome b and DNA hybridization data bearing on the phylogeny of swallows (Aves: Hirundinidae)

Cytochrome b sequence data from 17 species representing 16 genera of swallows (Aves: Hirundinidae) were compared with DNA-DNA hybridization data from the same species in a taxonomic congruence assessment of swallow phylogeny. In the process, subsets (partitions) of the cytochrome b sequence data were examined in light of the DNA hybridization distances to assess their potential phylogenetic informativeness. When the sequence data were weighted-with or without reference to the DNA hybridization data-they produced parsimony and maximum likelihood (but not distance) trees that were largely congruent with the DNA hybridization tree. To this extent, the cytochrome b data supported many of the phylogenetic conclusions based on the DNA hybridization tree and vice versa. However, the cytochrome b data produced largely unresolved trees when branch robustness was tested by bootstrapping and other methods. This poor resolution appeared to be caused by a lack of hierarchical structure in the cytochrome b distances, which were confined to a narrow range (between 10-13%), compressed by saturation, and noisy. Partition analysis by codon sites and protein domains yielded typical avian cytochrome b patterns, except for idiosyncrasies attributable to the genetic divergence level of swallows in comparison to other groups of birds whose cytochrome b sequences have been analyzed.     

Sequences from 14 mitochondrial genes provide a well-supported phylogeny of the Charadriiform birds congruent with the nuclear RAG-1 tree

Because of the difficulties of constructing a robust phylogeny for Charadriiform birds using morphological characters, recent studies have turned to DNA sequences to resolve the systematic uncertainties of family-level relationships in this group. However, trees constructed using nuclear genes or the mitochondrial Cytochrome b gene suggest deep-level relationships of shorebirds that differ from previous studies based on morphology or DNA-DNA hybridization distances. To test phylogenetic hypotheses based on nuclear genes (RAG-1, myoglobin intron-2) and single mitochondrial genes (Cytochrome b), approximately 13,000 bp of mitochondrial sequence was collected for one exemplar species of 17 families of Charadriiformes plus potential outgroups. Maximum likelihood and Bayesian analyses show that trees constructed from long mitochondrial sequences are congruent with the nuclear gene topologies [Chardrii (Lari, Scolopaci)]. Unlike short mitochondrial sequences (such as Cytochrome b alone), longer sequences yield a well-supported phylogeny for shorebirds across various taxonomic levels. Examination of substitution patterns among mitochondrial genes reveals specific genes (especially ND5, ND4, ND2, and COI) that are better suited for phylogenetic analyses among shorebird families because of their relatively homogeneous nucleotide composition among lineages, slower accumulation of substitutions at third codon positions, and phylogenetic utility in both closely and distantly related lineages. For systematic studies of birds in which family and generic levels are examined simultaneously, we recommend the use of both nuclear and mitochondrial sequences as the best strategy to recover relationships that most likely reflect the phylogenetic history of these lineages.     

Phylogenetic Analysis of the Hoplolaiminae Inferred from Combined D2 and D3 Expansion Segments of 28S rDNA

DNA sequences of the D2-D3 expansion segments of the 28S gene of ribosomal DNA from 23 taxa of the subfamily Hoplolaiminae were obtained and aligned to infer phylogenetic relationships. The D2 and D3 expansion regions are G-C rich (59.2%), with up to 20.7% genetic divergence between Scutellonema brachyurum and Hoplolaimus concaudajuvencus. Molecular phylogenetic analysis using maximum likelihood and maximum parsimony was conducted using the D2-D3 sequence data. Of 558 characters, 254 characters (45.5%) were variable and 198 characters (35.4%) were parsimony informative. All phylogenetic methods produced a similar topology with two distinct clades: One clade consists of all Hoplolaimus species while the other clade consists of the rest of the studied Hoplolaiminae genera. This result suggests that Hoplolaimus is monophyletic. Another clade consisted of Aorolaimus, Helicotylenchus, Rotylenchus, and Scutellonema species. Phylogenetic analysis using the outgroup species Globodera rostocheinsis suggests that Hoplolaiminae is paraphyletic. In this study, the D2-D3 region had levels of DNA sequence divergence sufficient for phylogenetic analysis and delimiting species of Hoplolaiminae.     

Pseudoplusia includens single nucleopolyhedrovirus: Genetic diversity,phylogeny and hypervariability of the pif-2 gene

The soybean looper (Pseudoplusia includens Walker, 1857) has become a major pest of soybean crops in Brazil. In order to determine the genetic diversity and phylogeny of variants of Pseudoplusia includens single nucleopolyhedrovirus (PsinSNPV-IA to -IG), partial sequences of the genes lef-8, lef-9, pif-2, phr and polh were obtained following degenerate PCR and phylogenetic trees constructed using maximum parsimony and Bayesian methods. The aligned sequences showed polymorphisms among the isolates, where the pif-2 gene was by far the most variable and is predicted to be under positive selection. Furthermore, some of the pif-2 DNA sequence mutations are predicted to result in significant amino acid substitutions, possibly leading to changes in oral infectivity of this baculovirus. Cladistic analysis revealed two closely related monophyletic groups, one containing PsinNPV isolates IB, IC and ID and another containing isolates IA, IE, IF and IG. The phylogeny of PsinSNPV in relation to 56 other baculoviruses was also determined from the concatenated partial LEF-8, LEF-9, PIF-2 and POLH/GRAN deduced amino acid sequences, using maximum-parsimony and Bayesian methods. This analysis clearly places PsinSNPV with the Group II Alphabaculovirus, where PsinSNPV is most closely related to Chrysodeixis chalcites NPV and Trichoplusia ni SNPV.     

<Emphasis Type="Italic">Gallus gallus</Emphasis> aggrecan gene-based phylogenetic analysis of selected avian taxonomic groups

Mitochondrial DNA (mtDNA) sequences remain the most widely used for phylogenetic analysis in birds. A major limitation of mtDNA sequences, however, is that mitochondria genes are inherited as a single linkage group. Here we describe the use of a 540-bp DNA sequence corresponding to the G3 domain of Gallus gallus nuclear aggrecan gene (AGC1) for phylogenetic analysis of the main groups of Galliformes including Phasianidae, Numididae, and Odontophoridae. We also included species from Cracidae and Megapodiidae which are considered by some as Craciformes and others, including here as Galliformes. The uncorrected sequence divergence of the G3 fragments ranges from 1 among the grouses to 36% between some of the distant groups within Galliformes. These sequences contain 39–48% AT nucleotides and the ratios of transition versus transversion are above 1.5 in majority of the comparisons. Using G3 sequences from an Anseriform, Oxyura jamaicensis, as out-groups, phylogenetic trees were obtained using maximum parsimony and distance algorithms and bootstrap analyses. These trees were consistent with those described using Avian sarcoma and leucosis virus gag genes and those from amino acid sequences of hemoglobin and lysozyme c. Our data also support relationships among Galliformes which were defined using mtDNA sequences. In addition to the general support of the five main families of Galliformes, our data are also consistent with previous work that showed Francolinus africanus and Gallus gallus are in the same clade and that Tetraoninae is a well-supported monophyletic subfamily within Phasianidae. The results presented here suggest that the AGC1 sequences meet the criterion of novel nuclear DNA sequences that can be used to help resolve the relationships among Galliformes.     

基于线粒体和核基因序列的蜜蜂属系统发育分析

文章测定了中国分布的蜜蜂属(Apis)5种蜜蜂22个样本的线粒体基因ND2、CO2、16S rRNA以及核基因ITPR的序列,对序列的碱基组成和蜜蜂种间的遗传距离进行了分析。结合下载的蜜蜂属其他4个种的相关序列,采用最大简约法、邻接法和最大似然法重建了蜜蜂属系统发育关系。系统发育分析结果支持蜜蜂属划分为3个类群,即小蜜蜂类群(包括小蜜蜂和黑小蜜蜂)、大蜜蜂类群(包括大蜜蜂和黑大蜜蜂)和穴居蜜蜂类群(西方蜜蜂、东方蜜蜂、沙巴蜂、苏拉威西蜂、绿努蜂),且小蜜蜂类群较早分化。结果还显示,我国海南岛的大蜜蜂和大陆的大蜜蜂之间可能存在较大的遗传分歧。     

Complete nucleotide sequences and gene organization of mitochondrial genome of Bufo gargarizans

The complete mitochondrial genome of Bufo gargarizans was sequenced using overlapping polymerase chain reaction (PCR) amplicons (GenBank Accession No. DQ275350). The genome is 17,277 base pairs in length, containing 13 protein-coding genes (ATP6, ATP8, COI-III, ND1-6, ND4L, Cyt b), 2 ribosomal RNAs (12S rRNA and 16S rRNA), 22 transfer RNAs and a putative control region. We analyzed the sequence using bioinformatics methods comparing the obtained mtDNA sequence with other toads and frogs. Based on the concatenated nucleotide sequences of protein-coding genes, we constructed a phylogenetic tree with maximum likelihood (ML) and maximum parsimony (MP) methods and discussed the phylogenetic relationships among 11 species of Anura.     

Molecular systematics of a speciose, cosmopolitan songbird genus: defining the limits of, and relationships among, the Turdus thrushes

The avian genus Turdus is one of the most speciose and widespread of passerine genera. We investigated phylogenetic relationships within this genus using mitochondrial DNA sequence data from the ND3, ND2 and cytochrome b genes. Our sampling of Turdus included 60 of the 65 extant species currently recognized, as well as all four species from three genera previously shown to fall inside Turdus (Platycichla, Nesocichla, and Cichlherminia). Phylogenetic trees based on maximum likelihood and maximum parsimony algorithms were congruent. Most of the Turdus taxa sampled fall into one of four clades: an African clade, a Central American-Caribbean clade, a largely South American clade, and a Eurasian clade. Still other taxa are placed either at the base of Turdus, or as links between clades. In no instance is any continent reciprocally monophyletic for the species distributed on it. A general lack of nodal support near the base of the phylogeny seems related to a rapid intercontinental establishment of the major clades within Turdus very early in the history of the genus. The monotypic genus Psophocichla is distantly related to, but clearly the sister of, Turdus rather than a constituent member of it.     

Phylogenetic relationships of honey bees (Hymenoptera:Apinae:Apini) inferred from nuclear and mitochondrial DNA sequence data

Two different genomic regions (ND2 mitochondrial gene and EF1-alpha intron) were PCR amplified, cloned and sequenced for the ten known honey bee species collected within their natural range distribution. DNA sequences were analyzed using parsimony, distance and maximum likelihood methods to investigate phylogenetic relationships within Apis. The phylogenetic analyses strongly supported the basic topology recoverable from morphometric analysis, grouping the honey bees into three major clusters: giant bees (A. dorsata, A. binghami, and A. laboriosa), dwarf bees (A. andreniformis and A. florea), and cavity-nesting bees (A. mellifera, A. cerana, A. koschevnikovi, A. nuluensis, and A. nigrocincta). However, the clade of Asian cavity-nesting bees included paraphyletic taxa. Exemplars of Apis cerana collected from divergent portions of its range were less related to each other than were sympatric A. cerana, A. nuluensis, and A. nigrocincta taxa. Nucleotide sequence divergence between allopatrically distributed western (A. mellifera) and eastern (A. cerana, A. koschevnikovi, A. nigrocincta, and A. nuluensis) cavity-nesting species, around 18% for the mitochondrial gene and 10-15% for the nuclear intron, suggested an earlier divergence for these groups than previously estimated from morphometric and behavioral studies. This latter finding neccessitates reevaluation of the hypothesized origin of extant European, African, and west Asian Apis mellifera. Sequence divergence between A. laboriosa and A. dorsata was consistent with behavioral data and supports the species status of A. laboriosa.     

切叶蚁亚科七属十二种的分子系统学研究

测定了切叶蚁亚科7属12种的线粒体CO1、CO2的部分基因及完整的tRNA_Leu基因DNA序列,对DNA序列进行了分析,对tRNA_Leu 基因进行了二级结构分析;根据DNA序列数据和氨基酸序列数据,以臭蚁亚科的Forelius chalybaeus作为外群,采用最大似然法(ML)、最大简约法(MP)、邻接法(NJ)、未加权组对算术平均法(UPGMA)构建分子系统树,通过自举检验,得到自举置信水平,以此检验该分子系统树的可靠性。研究结果显示,基于以上基因的分子系统分析与传统分类分析的结果基本一致,且在属级的一致性高于种级的一致性。