以ND4L和ND4基因为标记探讨黑腹果蝇种组的系统发育关系

多年来的形态学、染色体组学以及DNA序列几个方面的研究均没有很好地阐明黑腹果蝇种组内的系统发育关系。本实验测定了33个样品的ND4和31个样品的ND4L基因序列,以D．obscuroides为外群,用最大简约法和Bayesian法分别构建进化树。结果表明两种方法构建的拓扑结构一致,而且大部分支系的支持率较高。整个黑腹果蝇种组分成三大谱系：1）montium种亚组;2）ananssae种亚组;3）Oriental种亚组（melanogaster、ficsphila、eugracilis、elegans、suzukii、takahashii）。montium是最早分化的种亚组。在第三谱系中,melanogaster分化得最早;然后依次是ficsphila,eugracilis,elegans;suzukii与takahashii为姐妹种亚组,最后分化。     

Phylogenetic relationships of Drosophila melanogaster species group deduced from spacer regions of histone gene H2A-H2B

Nucleotide sequences of the spacer region of the histone gene H2A-H2B from 36 species of Drosophila melanogaster species group were determined. The phylogenetic trees were reconstructed with maximum parsimony, maximum likelihood, and Bayesian methods by using Drosophila pseudoobscura as the out group. Our results show that the melanogaster species group clustered in three main lineages: (1). montium subgroup; (2). ananassae subgroup; and (3). the seven oriental subgroups, among which the montium subgroup diverged first. In the third main lineage, suzukii and takahashii subgroups formed a clade, while eugracilis, melanogaster, elegans, ficusphila, and rhopaloa subgroups formed another clade. The bootstrap values at subgroup levels are high. The phylogenetic relationships of these species subgroups derived from our data are very different from those based on some other DNA data and morphology data.     

The phylogeny of the subgroups within the melanogaster species group: likelihood tests on COI and COII sequences and a Bayesian estimate of phylogeny

The relationships among the majority of the subgroups in the Drosophila melanogaster species group remain unresolved. We present a 2223basepair dataset for mitochondrial cytochrome oxidase I and cytochrome oxidase II for 43 species (including new data from 11 species), sampled to include the major subgroups. After a brief review of competing hypotheses for the ananassae, montium, suzukii, and takahashii subgroups, we combine the two genes based on a new use of the SH test and present KH and SH likelihood comparisons (Kishino and Hasegawa, 1989. J. Mol. Evol. 29, 170-179; Shimodaira and Hasegawa, 1999) to test the monophyly and placement of these subgroups within the larger species group. Although we find insignificant differences between the two suggested placements for the ananassae subgroup, the ananassae is sister to the rest of the subgroups in the melanogaster species group in every investigation. For the takahashii subgroup, although we cannot reject monophyly, the species are so closely related to the suzukii subgroup for these data that the two subgroups often form one clade. Finally, we present a Bayesian estimate of the phylogeny for both genes combined, utilizing a recently published method that allows for different models of evolution for different sites.     

The influence of eclosion timing on winter survival and triacylglycerol accumulation in four temperate species of Drosophila

Abstract. Diapause incidence, winter survival and triacylglycerol content were studied in temperate species of Drosophila by outdoor rearing in Sapporo (a cool-temperate region), northern Japan. In strains of D.subauraria and D.triauraria (cool-temperate species) from northern Japan, diapause was induced in adults having eclosed after early September, but in those having eclosed after mid October in strains of D.rufa and D.lutescens (warm-temperate species) from southern Japan. A subtropical strain of D.triauraria did not enter diapause. In the strains of cool-temperate species from northern Japan, about 70% survived until spring when eclosed in mid autumn, whereas when eclosed earlier and later flies had a lower ability to overwinter. The warm-temperate species and a subtropical strain of D.triauraria also survived longer when eclosed in mid autumn than when eclosed later, but they were unable to survive until spring. The triacylglycerol content was higher in the cool-temperate species from northern Japan than in the warm-temperate species and a subtropical strain of D.trauraria. In each species the triacylglycerol content of adults was higher when they eclosed in early and mid than in late autumn. It is assumed that triacylglycerol plays an important role in overwintering of these Drosophila species and the low triacylglycerol level is the primary cause of the low overwintering capacity of individuals eclosing in late autumn.     

ADAPTATIONS TO TEMPERATE CLIMATES AND EVOLUTION OF OVERWINTERING STRATEGIES IN THE DROSOPHILA MELANOGASTER SPECIES GROUP

The Drosophila melanogaster species group is considered to have originated in the tropics and only recently invaded temperate habitats. The temperate species of this group that were studied here may be subdivided into the warm-temperate species (D. lutescens and D. rufa) and the cool-temperate species (species of the auraria complex). The warm-temperate species were more cold-hardy than were their tropical relatives (D. takahashii or D. melanogaster) at the larval and imaginal stages, and the cool-temperate species were more cold-hardy than the warm-temperate species, although only at the imaginal stage. However, these species showed little or no intraspecific variation in cold-hardiness, in spite of great variation in winter temperature within the species' ranges. It is assumed that cold-hardiness is one of the main factors restricting their distributions at high latitudes and that it is the key for evolution of the warm- and cool-temperate species from their subtropical or warm-temperate ancestors. Both warm- and cool-temperate species had photoperiodically controlled reproductive diapause. In the cool-temperate species, the development of cold-hardiness was affected by diapause, but diapause had little or no effect on cold-hardiness in the warm-temperate species. Critical daylengths and the diapause rates varied from species to species according to variation in their overwintering plans and also varied geographically in consequence of their adaptation to local climates. Species showed different responses to temperature in preimaginal and ovarian development. These differences are considered to reflect adaptation to different environmental temperatures.     

Latitudinal pattern of mountain vegetation zonation in southern and eastern Asia

A new scheme of altitudinal and latitudinal vegetation zonation is proposed for eastern Asia. The latitudinal patterns of mountain vegetation zonation show a clear boundary at ca. 20°–30° N. For the tropical mountains south of 20° N, the altitudinal series includes tropical lowland, tropical lower montane, and tropical upper montane zones. For the temperate mountains north of 30° N, the series includes temperate lowland, temperate lower montane, and temperate upper montane zones. The mountains located between 20° and 30° N show a transitional zonation pattern; the lower two zones are comparable to the lower two of the tropical zonation (tropical lowland and tropical lower montane), and the upper two zones are comparable to those of the temperate zonation (temperate lower montane and temperate upper montane). The tropical upper montane zone is not found north of 20°–30° N, while the tropical lower montane zone reaches down to sea level and constitutes the temperate lowland zone. Thus the zonation between 20° and 30° N includes tropical lowland, tropical lower montane/temperate lowland, temperate lower montane, and temperate upper montane zones. The latitudinal series of lowland rain forests follows the scheme of climatic division into tropical, subtropical/warm-temperate, cool-temperate and cold-temperate, with a shift of the respective life forms, evergreen, evergreen notophyllous, deciduous, and evergreen needle-leaved. The tropical lower montane forest can be correlated to the horizontal subtropical/ warm-temperate zone. The temperate altitudinal and latitudinal zonations above 30° N are correlated and show an inclined parallel pattern from high altitudes in the south to low altitudes down to sea level in the north.     

Heat- and cold-shock responses and temperature adaptations in subtropical and temperate species of Drosophila

Accumulation of Hsp70 mRNA was investigated with relation to heat and cold tolerance in adult males of three Drosophila species. The subtropical lowland species (D. watanabei) and the cool-temperate species (D. triauraria) were more tolerant to heat than the subtropical highland species (D. trapezifrons), and the cool-temperate species were much more tolerant to cold than the two subtropical species. Thus, heat and cold tolerance was related to temperature conditions in the habitats. The threshold temperatures for the induction of Hsp70 mRNA at heat and cold were higher in D. watanabei than in D. trapezifrons or D. triauraria, but were not different between the latter two species in spite of the difference in their heat and cold tolerance. In D. trapezifrons, exposures to 0 degrees C for 12h and 6 degrees C for 24h killed about 40% of individuals, but the former treatment induced Hsp70 mRNA while the latter one did not. Thus, the relation between the heat- and cold-shock responses and temperature tolerance was not rigid in the species studied. In D. triauraria, the threshold temperatures for the induction of Hsp70 mRNA at heat and cold were lower when reared at a lower temperature.     

Molecular phylogeny of the Drosophila virilis section (Diptera: Drosophilidae) based on mitochondrial and nuclear sequences

Regardless of the well-documented virilis species group, most groups of the Drosophila virilis section have not been completely studied at molecular level since it was suggested. Therefore, phylogenetic relationships among and within species groups of the virilis section are generally unknown. In present paper, the complete mitochondrial ND2 gene and fragment of COI gene in combination with a nuclear gene, Adh coding region, were used to derive the most extensive molecular phylogeny to date for the Drosophila virilis section. A total of 111 individuals covering 61 species were sampled in this study. Novel phylogenetic findings included (1) support for the paraphyly of the melanica and robusta species group and at least two subgroups of the robusta species group, the lacertosa and okadai subgroups, were distinguished as paraphyletic taxa. In addition, (2) present results revealed the sister relationship between D. moriwakii and the robusta subgroup, conflicting with current taxonomy regarding D. moriwakii, which was shifted from the robusta species group to the melanica group. (3) In contrast to the robusta and melanica species groups, monophyly of the polychaeta species group, the angor group and the virilis group was confirmed, respectively. However, the monophyletic quadrisetata species group was resolved with uncertainty. (4) Our analyses of combined data set suggested close relationship between the quadrisetata species group and the unpublished clefta group, and the okadai subgroup is sister to the clade comprising of the quadrisetata and clefta species groups. Within the virilis section, D. fluvialis and three tropical species groups, the polychaeta group, the angor group and the repleta group, are found to branch off earlier than other ingroup taxa. This suggests that the virilis section might have originated in the Old World tropics. Besides, the derived status of the close affinities of the quadrisetata group, the clefta group, and the melanica and robusta groups is probably the result of their adaptation to forests between subtropical and cool-temperate climate. Based on the consideration of the phylogenetic placement of the species of the virilis section, we suggest that at least five independent migrations occurred from the Old World to the New World.     

Macroevolutionary relationships of species of Drosophila melanogaster group based on mtDNA sequences

The phylogenetic relationships among the Drosophila melanogaster group species were analyzed using approximately 1700 nucleotide-long sequences of the mitochondrial DNA. Phylogenetic analysis was performed using this region consisting of a part of the cytochrome b (cytb) coding gene, the entire coding sequences of tRNA-Leu, tRNA-Ser and the first subunit of NADH dehydrogenase (NADH1), and a part of the 16S-rRNA gene. The study of these sequences showed that this region of mtDNA is very invariable, as regards with the type of the genes that it contains, as well as the order that they are located on it. The resulting phylogenetic trees reveal a topology that separates the species into three main ancestral lines, leading to the following subgroups: (a) ananassae subgroup, (b) montium subgroup, and (c) melanogaster and Oriental subgroups. The inferred topology complements and generally agrees with previously proposed classifications based on morphological and molecular data.     

Cold and heat tolerance of drosophilid flies with reference to their latitudinal distributions

The relation between thermal tolerance and latitudinal distribution was studied with 30 drosophilid species collected from the cool-temperate region (Sapporo), the warm-temperate region (Tokyo and Kyoto) and the subtropical region (Iriomote island) in Japan. In addition, intraspecific variation was examined for five species collected from two localities. The subtropical strains of Scaptodrosophila coracina, Drosophila bizonata and D. daruma were less tolerant to cold than their temperate strains. However, the difference of cold tolerance between these two geographic strains was much smaller than the difference between the species restricted to the subtropical region and those occurring in the temperate region. In D. auraria and D. suzukii, no difference was observed in thermal tolerance between their cool- and warm-temperate strains. Thus, geographic variation in thermal tolerance within species was low or negligible. Interspecific comparisons by phylogenetic independent contrasts revealed that species which had the northern boundaries of their distributions at higher latitudes were generally more tolerant to cold than those which had their boundaries at lower latitudes. However, the data for some species did not agree with this trend. The use of man-protected warm places for overwintering, competition or predation would also affect their distributions. It also appeared that species which had their southern boundaries at higher latitudes were generally more cold-tolerant. The acquisition of cold tolerance may lower a flys capacity to compete, survive or reproduce in warmer climates. On the other hand, no relation was observed between heat tolerance and latitudinal distribution. Heat tolerance was higher in species inhabiting openlands or the forest canopy than in those inhabiting the forest understorey.     

Phylogeny of a paradigm lineage: the Drosophila melanogaster species group (Diptera: Drosophilidae)

Although Drosophila melanogaster is a paradigm eukaryote for biology, relationships of this species and the other 174 species in the melanogaster species group are poorly explored and ambiguous. Gene regions of Cytochrome oxidase II (mt:CoII ), Alcohol dehydrogenase ( Adh ) and hunchback ( hb ) were sequenced and analysed phylogenetically to test prior hypotheses of relationships for the group based on chromosomes, morphology, and 28S rRNA gene sequences. A simultaneous cladistic analysis of the three newly sequenced gene regions produced a single well-resolved phylogeny for 49 exemplar species representing eight subgroups. Monophyly of each of the ananassae , melanogaster , montium , and takahashii subgroups is supported; the suzukii subgroup is polyphyletic. This phylogeny is consistent with variation in significant morphological structures, such as the male sex comb on the fore tarsus. The broad range of morphological variation among these species is interpreted and the applicability to evolution and developmental investigations is discussed. This phylogeny facilitates comparative investigations, such as gene family evolution, transposable element transmission, and evolution of morphological structures. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 76 , 21–37.     

黑腹果蝇种组的核型与进化研究

观察了国内黑腹果蝇种组34种果蝇的有丝分裂中期核型,其中首次描述了一些新核型。系统地分析了黑腹果蝇种组8个种亚组之间的核型进化关系及种间亲缘关系。结果是:elegans种亚组的核型为A型;eugracilis、melanogaster和ficusphila种亚组的核型为C型;takahashii和suzukii种亚组的核型为C型和D型;montium种亚组的核型为B、C、C’、D、D’、和E型;ananassae种亚组的核型为F、G和H型。从核型分化的角度可以将黑腹果蝇种组分为5个谱系:elegans,eugracilis-melanogaster-ficusphila,takkahashii-suzukii,montium,ananassae。这与2004年Yang等的观点基本一致,正好从核型进化的角度验证了Yang通过DNA序列分析所得到的结果。差别只在于elegans种亚组,作者把它单独列为一支,认为是祖先种亚组。通过选取同一种果蝇的几个不同地域单雌系的核型分析,结果表明:同一种果蝇的核型存在地域差异。这种差异可能是由于不同生境造成,也可能是本身进化程度的差异,或是两种因素相互作用的结果。     

Energy storage during reproductive diapause in the Drosophila melanogaster species group

Summary Temperate species of the Drosophila melanogaster group enter reproductive diapause for overwintering in response to short daylength. During the prediapause period they accumulate triacylglycerols, but not glycogen, as energy resources. The capacity for storing triacylglycerols differs between species, and appears to be closely correlated with diapause and cold-hardiness; cool-temperate species, such as those of the auraria species complex, which enter a deep diapause and are highly cold-hardy, accumulate larger quantities of triacylglycerols than warm-temperate species, such as D. rufa and D. lutescens, which enter a weak diapause and are less cold-hardy. Among the cool-temperate spcies, D. subauraria occurs at a higher latitude and has the greatest capacity for accumulating triacylglycerols. A subtropical species, D. takahashii, which has no diapause in nature and is not cold-hardy, is unable to store the same quantities of triacylglycerols as temperate species.     

Phylogenetic utility of mitochondrial COI and nuclear Gpdh genes in Drosophila

Phylogenetic utility of the mitochondrial COI (cytochrome oxidase subunit I) and nuclear Gpdh (glycerol-3-phosphate dehydrogenase) genes was studied in the Drosophila melanogaster species group. The rate of substitution was higher in the COI gene than in the Gpdh gene. In addition, multiple substitutions, not only for transitional but also for transversional substitutions, occurred faster in the COI gene. None of the trees obtained using the COI gene supported the well-established monophyly of the ananassae subgroup. In addition, the incongruence length difference test, Templeton test, and partitioned Bremer support revealed that the trees based on the COI data are considerably different from those based on the Gpdh and the combined data set. Thus, the COI gene did not show good phylogenetic performance in the melanogaster group. The present analyses based on the Gpdh gene and the combined data set revealed that the ananassae subgroup branched off first in the melanogaster group followed by the montium subgroup and further by the melanogaster subgroup in contrast to the most recent phylogenetic hypothesis based on Amy multigenes.     

Phylogenetic incongruence in the Drosophila melanogaster species group

Drosophila melanogaster and its close relatives are used extensively in comparative biology. Despite the importance of phylogenetic information for such studies, relationships between some melanogaster species group members are unclear due to conflicting phylogenetic signals at different loci. In this study, we use twelve nuclear loci (eleven coding and one non-coding) to assess the degree of phylogenetic incongruence in this model system. We focus on two nodes: (1) the node joining the Drosophila erecta-Drosophila orena, Drosophila melanogaster-Drosophila simulans, and Drosophila yakuba-Drosophila teissieri lineages, and (2) the node joining the lineages leading to the melanogaster, takahashii, and eugracilis subgroups. We find limited evidence for incongruence at the first node; our data, as well as those of several previous studies, strongly support monophyly of a clade consisting of D. erecta-D. orena and D. yakuba-D. teissieri. By contrast, using likelihood based tests of congruence, we find robust evidence for topological incongruence at the second node. Different loci support different relationships among the melanogaster, takahashii, and eugracilis subgroups, and the observed incongruence is not easily attributable to homoplasy, non-equilibrium base composition, or positive selection on a subset of loci. We argue that lineage sorting in the common ancestor of these three subgroups is the most plausible explanation for our observations. Such lineage sorting may lead to biased estimation of tree topology and evolutionary rates, and may confound inferences of positive selection.     

Horizontal transmission versus vertical inheritance of P elements in Drosophila and Scaptomyza: has the M-type subfamily spread from East Asia?

Polymerase chain reaction (PCR) screening for P elements was carried out in 77 species with a primer set highly specific for the M-type subfamily. In the course of this search M-type elements were detected in 29 species: In the melanogaster (subgroups montium and rhopaloa ) and obscura species groups of Drosophila (25 out of 71 species examined), and in the genus Scaptomyza (four out of six species). M-type elements are present in all species of the montium subgroup investigated so far (21), but occur only sporadically in other groups. Within the montium subgroup 20 species possess only incomplete copies, only one species ( D. lacteicornis ) harbours apparently full-sized elements. In contrast, outside the montium subgroup almost all species with M-type elements carry full-sized copies suggesting transpositional activity, at least in the recent past. The interior section of the full-sized M-type element of D. lacteicornis was partially sequenced (936 bp). In addition, the complete sequences of four internally deleted M-type elements of D. lacteicornis, D. rufa, D. quadraria , and D. triauraria were determined. Sequence comparisons (including sequence data from previous investigations) revealed striking discrepancies between P element phylogeny and the cladogenesis of their host species. Among several possible pathways for interspecific transfers of M-type elements, we favour the hypothesis assuming the invasion of Scaptomyza as well as the obscura group species of Drosophila via independent transmission routes originating from Asian species of the montium subgroup of Drosophila . The logical geographic scenario for these events would be East-Asia.     

The heat shock genes in theDrosophila montium subgroup: Chromosomal localization and evolutionary implications

The hsp70, hsp83, hsrω, and the small heat shock protein genes were mapped on the polytene chromosomes of six species, representative of the geographical distribution of the Drosophila montium subgroup of the melanogaster species group. In addition, based on hybridization conditions, the putative locus of the hsp68 gene is given. In contrast to the situation in the melanogaster subgroup species, the hsp70 locus is single in the montium species. The hsp83, hsrωand the small hsp loci are also single in the montium genomes studied here, a common feature of all Drosophila species. Among the hsp genes studied, the small hsp genes and the hsrω-homologous sequences exhibit a higher degree of divergence between the melanogaster and the montium subgroups. Our results support the idea that the montium subgroup species has a genome organization closer to that of the common ancestor compared with the melanogaster subgroup species. Received: 25 July 1995; in revised form: 31 January 1996 / Accepted: 1 April 1996     

果蝇亚群中六个种的求爱歌的研究：对ipi作用的探究

据认为果蝇求爱歌的脉冲间隔(ipi)在种特异性配偶认识系统(SMRS)中起着重要的作用。果蝇D.takahashii亚群中各物种求爱歌的ipi值和种间亲缘关系的相关性如何?迄今尚未见报道。我们测定了此亚群中能饲养存活的6个种的ipi,并用O’Farrell双向电泳方法及杂交实验研究了它们之间的亲缘关系。在近缘种D.takahashii和D.lutescens之间,D.takahashii和D.paralutea之间,D.lutescens和D.paralutea之间,其求爱歌的ipi值,不论平均数或众数都相差甚远。而D.paralutea和D.prostipennis是2个亲缘关系较远的种,两者不能杂交,但其ipi的平均数在统计学上无差异,众数亦很相近。本实验可导出这样的见解:ipi值在不同果蝇种群或亚群的SMRS中的作用可能并不相同。在D.takahashii亚群中ipi值对于杂交成败似乎不起支配性作用。     

中国海毛颚类物种多样性的研究

中国海已记录毛颚类有37种,可分为3个生态类群,即暖水性、暖温性和深水类群。种数是由北往南、由近岸向外海递增。中国海毛颚类可划分暖温带区系、热带- 暖温带混合区系和热带大洋区系。大多数种类广泛分布于印度洋、大西洋和太平洋等水域。     

Basal relationships in the Drosophila melanogaster species group

The Drosophila melanogaster species group is a popular model for evolutionary studies due to its morphological and ecological diversity and its inclusion of the model species D. melanogaster. However, phylogenetic relationships among major lineages within this species group remain controversial. In this report, the phylogeny of 10 species representing each of the well-supported monophyletic clades in the melanogaster group was studied using the sequences of 14 loci that together comprise 9493 nucleotide positions. Combined Bayesian analysis using gene-specific substitution models produced a 100% credible set of two trees. In the strict consensus of these trees, the ananassae subgroup branches first in the melanogaster species group, followed by the montium subgroup. The remaining lineages form a monophyletic clade in which D. ficusphila and D. elegans branch first, followed by D. biarmipes, D. eugracilis, and the melanogaster subgroup. This strongly supported phylogeny resolves most basal relationships in the melanogaster species group, and provides a framework that can be extended in the future to encompass more species.