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1.
Carolyn J. Lawrence Russell L. Malmberg Michael G. Muszynski R. Kelly Dawe 《Journal of molecular evolution》2002,54(1):42-53
We have reconstructed the evolution of the anciently derived kinesin superfamily using various alignment and tree-building
methods. In addition to classifying previously described kinesins from protists, fungi, and animals, we analyzed a variety
of kinesin sequences from the plant kingdom including 12 from Zea mays and 29 from Arabidopsis thaliana. Also included in our data set were four sequences from the anciently diverged amitochondriate protist Giardia lamblia. The overall topology of the best tree we found is more likely than previously reported topologies and allows us to make the
following new observations: (1) kinesins involved in chromosome movement including MCAK, chromokinesin, and CENP-E may be
descended from a single ancestor; (2) kinesins that form complex oligomers are limited to a monophyletic group of families;
(3) kinesins that crosslink antiparallel microtubules at the spindle midzone including BIMC, MKLP, and CENP-E are closely
related; (4) Drosophila NOD and human KID group with other characterized chromokinesins; and (5) Saccharomyces SMY1 groups with kinesin-I sequences, forming a family of kinesins capable of class V myosin interactions. In addition, we
found that one monophyletic clade composed exclusively of sequences with a C-terminal motor domain contains all known minus
end-directed kinesins.
Received: 20 February 2001 / Accepted: 5 June 2001 相似文献
2.
Jennifer Pastorini Michael R.J. Forstner Robert D. Martin Don J. Melnick 《Journal of molecular evolution》1998,47(1):32-41
The New World monkeys are divided into two main groups, Callitrichidae and Cebidae. Callimico goeldii shares traits with both the Cebidae and the Callitrichidae. Recent morphological phyletic studies generally place Callimico as the most basal member of the Callitrichidae. In contrast, genetic studies (immunological, restriction fragment, and sequence
data) have consistently placed Callimico somewhere within the Callitrichidae, not basal to this clade. A DNA sequence data set from the terminal 236 codons of the
mitochondrial ND4 gene and the tRNAHis, tRNASer, and tRNALeu genes was generated to clarify the position of Callimico. The sequences of 887 base pairs were analyzed by maximum-parsimony, neighbor-joining, and maximum-likelihood methods. The
results of these various methods are generally congruent and place Callimico within the Callitrichidae between the marmosets (Callithrix and Cebuella) and the tamarins (Saguinus and Leontopithecus). Combined analyses of all suitable nuclear and mitochondrial gene sequences confirm the position of Callimico between the marmosets and the tamarins. As available molecular evidence indicates that Callimico is more closely related to the marmosets than to the tamarins, a reconsideration of the morphological evidence in light of
the consensus tree from DNA sequence analyses is warranted. The marmosets and tamarins share four morphological characters
(loss of the third molar, loss of the hypocone, reduced body size, reproductive twinning). Dwarfism may have evolved repeatedly
among the Callitrichidae. It is well-known that the loss of a character can occur many times independently. The reproduction
of marmosets and tamarins is extremely specialized and it is difficult to imagine that this complex and unique twinning system
evolved separately in marmosets and tamarins. However, it is possible that a secondary reversal to single offspring took place
in Callimico.
Received: 20 March 1997 / Accepted: 17 December 1997 相似文献
3.
Gilles Bena Marie-France Jubier Isabelle Olivieri Bernard Lejeune 《Journal of molecular evolution》1998,46(3):299-306
We have estimated the potential phylogenetic utility of the ribosomal external transcribed spacer (ETS) from the nuclear
ribosomal region. The ETS was sequenced from 13 annual Medicago (Fabaceae) species upstream a highly conserved motive which was found among many different organisms. In the genus Medicago, the ETS was found to evolve 1.5 times faster than the internal transcribed spacer and to be 1.5 times more informative. Reduced
ribosomal maturation process constraints on ETS are proposed to explain the different evolutionary rates between the two spacers.
Maximal phylogenetic resolution and support was obtained when the two spacers were analyzed together. No incongruence between
the two spacers was found and ETS appears to be a valuable source of information for solidifying ITS plant phylogeny. The
phylogeny obtained in Medicago suggests that none of the three subsections included in the study is monophyletic.
Received: 15 April 1997 / Accepted: 29 July 1997 相似文献
4.
Marie Claude Leclerc Véronique Barriel Guillaume Lecointre Bruno de Reviers 《Journal of molecular evolution》1998,46(1):115-120
Sequences from the two ribosomal DNA internal transcribed spacers (ITS1 and ITS2) were compared among five species of Fucus. Based on the present taxon sampling, parsimony analysis showed that Fucus serratus is the sister-group of the remaining Fucus species when Ascophyllum nodosum was used as an outgroup. The topology of the tree was (Fucus serratus (F. lutarius (F. vesiculosus (F. spiralis+F. ceranoides)))). The extremely low variation observed suggests a very recent radiation of the genus which supports the view widely accepted
that the Fucales are among the most evolutionarily advanced of the brown algae. We further note that sequence differences
between Fucus and Ascophyllum were 28%: this does not rule out the utility of ITS sequences within the Fucaceae. The very low number of informative positions
allows to demonstrate empirically that distance matrix methods group on the basis of symplesiomorphies.
Received: 17 February 1997 / Accepted: 17 April 1997 相似文献
5.
A Phylogenetic Study of the Origin of the Domestic Pig Estimated from the Near-Complete mtDNA Genome 总被引:18,自引:0,他引:18
The near-complete pig mtDNA genome sequence (15,997 bp) was determined from two domestic pigs (one Chinese Meishan and one
Swedish Landrace) and two European wild boars. The sequences were analyzed together with a previously published sequence representing
a Swedish domestic pig. The sequences formed three distinct clades, denoted A, E1, and E2, with considerable sequence divergence
between them (0.8–1.2%). The results confirm our previous study (based on the sequence of the cytochrome B gene and the control
region only) and provide compelling evidence that domestication of pigs must have occurred from both an Asian and a European
subspecies of the wild boar. We estimated the time since the divergence of clade A (found in Chinese Meishan pigs) and E1
(found in European domestic pigs) at about 900,000 years before present, long before domestication about 9000 years ago. The
pattern of nucleotide substitutions among the sequences was in good agreement with previous interspecific comparisons of mammalian
mtDNA; the lowest substitution rates were observed at nonsynonymous sites in protein-coding genes, in the tRNA and rRNA genes,
while the highest rates were observed at synonymous sites and in the control region. The presence of Asian clade A in some
major European breeds (Large White and Landrace) most likely reflects the documented introgression of Asian germplasm into
European stocks during the 18th and 19th centuries. The coexistence of such divergent mtDNA haplotypes for 100+ generations
is expected to lead to the presence of recombinant haplotypes if paternal transmission and recombination occur at a low frequency.
We found no evidence of such recombination events in the limited sample studied so far.
Received: 19 April 2000; Accepted: 15 November 2000 相似文献
6.
D. Hepperle H. Nozaki S. Hohenberger V.A.R. Huss E. Morita L. Krienitz 《Journal of molecular evolution》1998,47(4):420-430
Four genera of the Phacotaceae (Phacotus, Pteromonas, Wislouchiella, Dysmorphococcus), a family of loricated green algal flagellates within the Volvocales, were investigated by means of transmission electron
microscopy and analysis of the nuclear encoded small-subunit ribosomal RNA (18S rRNA) genes and the plastid-encoded rbcL genes.
Additionally, the 18S rDNA of Haematococcus pluvialis and the rbcL sequences of Chlorogonium elongatum, C. euchlorum, Dunaliella parva, Chloromonas serbinowii, Chlamydomonas radiata, and C. tetragama were determined. Analysis of ultrastructural data justified the separation of the Phacotaceae into two groups. Phacotus, Pteromonas, and Wislouchiella generally shared the following characters: egg-shaped protoplasts, a single pyrenoid with planar thylakoid double-lamellae,
three-layered lorica, flagellar channels as part of the central lorica layer, mitochondria located in the central cytoplasm,
lorica development that occurs in mucilaginous zoosporangia that are to be lysed, and no acid-resistant cell walls. Dysmorphococcus was clearly different in each of the characters mentioned. Direct comparison of sequences of Phacotus lenticularis, Pteromonas sp., Pteromonas protracta, and Wislouchiella planctonica revealed DNA sequence homologies of ≥98.0% within the 18S gene and 93.9% within the rbcL gene. D. globosus was quite different from these species, with a maximum of 92.9% homology in the 18S rRNA and ≤86.6% in the rbcL gene. It
showed major similarities to the 18S rDNA of Dunaliella salina, with 95.3%, and to the rbcL sequence of Chlamydomonas tetragama, with 90.3% sequence homology. Additionally, the Phacotaceae sensu stricto exclusively shared 10 (rbcL: 4) characters which were present neither in other Chlamydomonadales nor in Dysmorphococcus globosus. Different phylogenetic analysis methods confirmed the hypothesis that the Phacotaceae are polyphyletic. The Phacotaceae sensu stricto form a stable cluster with affinities to the Dunaliellaes and possibly Haematococcus pluvialis. Dysmorphococcus globosus represented an independent lineage that is possibly related to Chlamydomonas moewusii and C. tetragama.
Received: 9 June 1997 / Accepted: 17 October 1997 相似文献
7.
Among Bacteria the carA and carB genes encoding the small (CarA) and large (CarB) subunits of carbamoylphosphate synthase (CPS) have been lost in certain
symbionts (Haemophylus influenzae) and in most obligate intracellular parasites (Chlamydiae, Spirochaetes, Mycoplasmatales, Rickettsiae) having genome sizes in the 0.7- to 1.1-Mb range. Compared to Bacteria, Archaea exhibit a more varied pattern of CPS gene
losses and an unusual propensity to incorporate CPS genes derived from both Bacteria and other Archaea. Schematically they
fall into three groups. Group 1 taxa (the crenarchaeon Aeropyrum pernix and the euryarchaea Pyrococcus horikoshi and Pyrococcus abyssii) lack CPS genes altogether. Group 2 taxa (comprising Halobacteriales, Thermoplasmales, Methanococcales, Methanomicrobiales,
Archaeoglobales) harbor CPS genes whose encoded CarB and CarA subunit proteins are ostensibly bacterial in origin; that is,
they are intermixed with bacterial homologues on a phylogeny of concatenated CarA and CarB sequences and are not distinguishable
from bacterial sequences after searching for domain-specific amino acid residue positions. Group 3 taxa (the crenarchaea Pyrobaculum aerophilum, Sulfolobus solfataricus, and Sulfolobus tokodaii and the euryarchaeon Pyrococcus furiosus) harbor CPS genes whose encoded proteins appear to be archaeal: consistent with an archaeal origin, the CarA and CarB sequences
in this group possess both unique signatures and signatures affiliating them to Eukarya. Based on the topology of the clade
comprising the four Group 3 taxa, we argue that CPS genes of P. furiosus (a euryarchaeon) and those of the crenarchaea P. aerophilum, S. solfataricus, and S. tokodaii are of a single type, resulting from the two genes being laterally transferred from a crenarchaeon to P. furiosus. 相似文献
8.
The members of the PKA regulatory subunit family (PKA-R family) were analyzed by multiple sequence alignment and clustering
based on phylogenetic tree construction. According to the phylogenetic trees generated from multiple sequence alignment of
the complete sequences, the PKA-R family was divided into four subfamilies (types I to IV). Members of each subfamily were
exclusively from animals (types I and II), fungi (type III), and alveolates (type IV). Application of the same methodology
to the cAMP-binding domains, and subsequently to the region delimited by β-strands 6 and 7 of the crystal structures of bovine
RIα and rat RIIβ (the phosphate-binding cassette; PBC), proved that this highly conserved region was enough to classify unequivocally
the members of the PKA-R family. A single signature sequence, F–G–E–[LIV]–A–L–[LIMV]–x(3)–[PV]–R–[ANQV]–A, corresponding to
the PBC was identified which is characteristic of the PKA-R family and is sufficient to distinguish it from other members
of the cyclic nucleotide-binding protein superfamily. Specific determinants for the A and B domains of each R-subunit type
were also identified. Conserved residues defining the signature motif are important for interaction with cAMP or for positioning
the residues that directly interact with cAMP. Conversely, residues that define subfamilies or domain types are not conserved
and are mostly located on the loop that connects α-helix B′ and β strand 7.
Received: 2 November 2000/Accepted: 14 June 2001 相似文献
9.
Christine P. Piotte Airlie K. Hunter Craig J. Marshall Murray R. Grigor 《Journal of molecular evolution》1998,46(3):361-369
Three proteins have been identified in the milk of the common brush tail possum, Trichosurus vulpecula that from sequence analysis are members of the lipocalin family. They include β-lactoglobulin, which appears to have two
forms; a homologue to the late-lactation protein found in tammar, Macropus eugenii; milk; and a novel protein termed trichosurin. Whereas β-lactoglobulin and trichosurin are both expressed throughout lactation, the late-lactation protein is not detected
in samples taken before days 100–110 of lactation. The cDNAs encoding each of these proteins have been isolated from cDNA
libraries prepared using possum mammary mRNA and sequenced. Phylogenetic analysis showed that the T. vulpeculaβ-lactoglobulin, along with two other macropod β-lactoglobulins, forms a subclass of β-lactoglobulins distinct from those
for eutherian mammals; both marsupial late-lactation proteins appear to have similarities to a family of odorant-binding proteins,
whereas trichosurin has similarities to the major urinary proteins of rodents.
Received: 28 October 1996 / Accepted: 19 May 1997 相似文献
10.
We analyzed the phylogenetic relationship between the species of Lordiphosa and other Drosophilidae using alcohol dehydrogenase (Adh) gene sequences. The phylogenetic trees consistently show that the four species Drosophila kurokawai, D. collinella, D. stackelbergi, and D. clarofinis, which include three species groups of Lordiphosa, form a monophyletic clade. This clade is placed as a sister group to the willistoni and saltans groups of Sophophora. On the other hand, three species of Lordiphosa, D. tenuicauda, D. pseudotenuicauda, and D. acutissima, all of which belong to the tenuicauda group, are not shown to be related to the major Lordiphosa lineage. In the phylogenetic trees, these species are included into the clade comprised of Drosophila and Hirtodrosophila, although it remains uncertain whether the tenuicauda group is a monophyletic group or not. These results indicate that Lordiphosa is polyphyletic and that most of the members of the subgenus have a close relationship to the neotropical groups of Sophophora. The above conclusion is compatible with the hypothesis of Okada (Mushi [1963] 37:79–100) and Lastovka and Máca (Acta Ent Bohemoslov [1978] 75:404–420) that Lordiphosa is most closely related to Sophophora; in contrast, our results contradict the hypothesis of Grimaldi (Bull Am Mus Nat Hist [1990] 197:1–139) that Lordiphosa is a sister group to the genus Scaptomyza.
Received: 12 May 1999 / Accepted: 14 April 2000 相似文献
11.
Yuji Inagaki Yasuko Hayashi-Ishimaru Megumi Ehara Ikuo Igarashi Takeshi Ohama 《Journal of molecular evolution》1997,45(3):295-300
The chloroplasts of euglenophytes and dinoflagellates have been suggested to be the vestiges of endosymbiotic algae acquired
during the process of evolution. However, the evolutionary positions of these organisms are still inconclusive, and they have
been tentatively classified as both algae and protozoa. A representative gene of the mitochondrial genome, cytochrome oxidase
subunit I (coxI), was chosen and sequenced to clarify the phylogenetic positions of four dinoflagellates, two euglenophytes and one apicomplexan
protist. This is the first report of mitochondrial DNA sequences for dinoflagellates and euglenophytes. Our COXI tree shows clearly that dinoflagellates are closely linked to apicomplexan parasites but not with algae. Euglenophytes and
algae appear to be only remotely related, with euglenophytes sharing a possible evolutionary link with kinetoplastids. The
COXI tree is in general agreement with the tree based on the nuclear encoded small subunit of ribosomal RNA (SSU rRNA) genes,
but conflicts with that based on plastid genes. These results support the interpretation that chloroplasts present in euglenophytes
and dinoflagellates were captured from algae through endosymbioses, while their mitochondria were inherited from the host
cell. We suggest that dinoflagellates and euglenophytes were originally heterotrophic protists and that their chloroplasts
are remnants of endosymbiotic algae.
Received: 24 March 1997 / Accepted: 21 April 1997 相似文献
12.
A 314-bp fragment of the mitochondrial 12S rRNA gene from 21 cestodes species of eight families was synthesized by PCR with
specially designed primers. These allowed amplification of parasite DNA without concomitant synthesis of host DNA. Phylogenetic
trees were inferred from the sequence data using three methods (maximum parsimony, maximum likelihood, and Fitch–Margoliash).
At the major nodes all three trees were similar. For the first time the genus Mesocestoides could be arranged into the Cyclophyllidea and a narrow relationship between the Mesocestoididae, Taeniidae, Hymenolepididae,
Anoplocephalidae, and Dipylidiidae was shown. Members of the families Catenotaeniidae and a cluster of two families (Hymenolepididae
and Dilepididae) form two monophyletic groups which derive prior to the remaining families of this phylogenetic study. A third
and a fourth clear monophyletic group were formed by the Taeniidae and by the Mesocestoididae. A high degree of variation
within the examined 304-bp fragment was observed between two isolates of Taenia taeniaeformis, supporting often discussed genetic heterogeneity within this species. In contrast, only one nucleotide exchange was found
in 23 isolates of Echinococcus multilocularis of various geographic origin, indicating that this species is genetically homogenous.
Received: 1 October 1997 / Accepted: 4 December 1997 相似文献
13.
Analysis of the 18S rDNA sequences of five species of the family Dugesiidae (phylum Platyhelminthes, suborder Tricladida,
infraorder Paludicola) and eight species belonging to families Dendrocoelidae and Planaridae and to the infraorder Maricola
showed that members of the family Dugesiidae have two types of 18S rDNA genes, while the rest of the species have only one.
The duplication event also affected the ITS-1, 5.8S, ITS-2 region and probably the 28S gene. The mean divergence value between
the type I and the type II sequences is 9% and type II 18S rDNA genes are evolving 2.3 times more rapidly than type I. The
evolutionary rates of type I and type II genes were calibrated from biogeographical data, and an approximate date for the
duplication event of 80–120 million years ago was calculated. The type II gene was shown, by RT-PCR, to be transcribed in
adult individuals of Schmidtea polychroa, though at very low levels. This result, together with the fact that most of the functionally important positions for small-subunit
rRNA in prokaryotes have been conserved, indicates that the type II gene is probably functional.
Received: 24 March 1998 / Accepted: 17 March 1999 相似文献
14.
Thomas A. Gorr Barbara K. Mable Traute Kleinschmidt 《Journal of molecular evolution》1998,47(4):471-485
Phylogenetic relationships among reptiles were examined using previously published and newly determined hemoglobin sequences.
Trees reconstructed from these sequences using maximum-parsimony, neighbor-joining, and maximum-likelihood algorithms were
compared with a phylogenetic tree of Amniota, which was assembled on the basis of published morphological data. All analyses differentiated α chains into αA and αD types, which are present in all reptiles except crocodiles, where only αA chains are expressed. The occurrence of the αD chain in squamates (lizards and snakes only in this study) appears to be a general characteristic of these species. Lizards
and snakes also express two types of β chains (βI and βII), while only one type of β chain is present in birds and crocodiles.
Reconstructed hemoglobin trees for both α and β sequences did not yield the monophyletic Archosauria (i.e., crocodilians + birds) and Lepidosauria (i.e., Sphenodon+ squamates) groups defined by the morphology tree. This discrepancy, as well as some other poorly resolved nodes, might be
due to substantial heterogeneity in evolutionary rates among single hemoglobin lineages. Estimation of branch lengths based
on uncorrected amino acid substitutions and on distances corrected for multiple substitutions (PAM distances) revealed that
relative rates for squamate αA and αD chains and crocodilian β chains are at least twice as high as those of the rest of the chains considered. In contrast to
these rate inequalities between reptilian orders, little variation was found within squamates, which allowed determination
of absolute evolutionary rates for this subset of hemoglobins. Rate estimates for hemoglobins of lizards and snakes yielded
1.7 (αA) and 3.3 (β) million years/PAM when calibrated with published divergence time vs. PAM distance correlates for several speciation
events within snakes and for the squamate ↔ sphenodontid split. This suggests that hemoglobin chains of squamate reptiles
evolved ∼3.5 (αA) or ∼1.7 times (β) faster than their mammalian equivalents. These data also were used to obtain a first estimate of some
intrasquamate divergence times.
Received: 15 September 1997 / Accepted: 4 February 1998 相似文献
15.
Cristina Torti Ludvik M. Gomulski Anna R. Malacrida Pierre Capy Giuliano Gasperi 《Journal of molecular evolution》1998,46(3):288-298
Mariner elements were amplified using the polymerase chain reaction from two species of tephritid flies, Ceratitis rosa and Trirhithrum coffeae. The sequences were ∼1.3 kb in length. None of these elements appeared to be functional, as in every case the open reading
frame (ORF) was disrupted by the presence of frameshifts or stop codons. These elements, Crmar1 and Tcmar1, are very similar to the Ccmar1 element previously amplified from the closely related tephritid species C. capitata and are members of the mellifera subfamily of mariner elements. The phylogeny and pattern of divergence of these elements were examined in relation to the phylogeny of the host
species. It is highly probable that the elements were present in the ancestral lineage prior to the divergence of the three
species. The copy numbers of the elements within each species are very different, ranging from about 10 in T. coffeae to 5,000 in C. rosa. The possible mechanisms which determine the copy number of an element in the host genome are discussed.
Received: 25 April 1997 / Accepted: 31 July 1997 相似文献
16.
Molecular analyses have been used recently to refine our knowledge of phylogenetic relationships within the ciliated protozoa
(phylum Ciliophora). A current Hennigian phylogeny of the orders in the class Colpodea, based on light and electron microscopic
analyses, makes three important assumptions with regard to apomorphic character states, namely, (1) that the kreyellid silver
line evolved early in colpodean phylogeny, separating bryometopids, such as Bryometopus, from all other colpodeans; (2) that the macro–micronuclear complex is an autapomorphy of the cyrtolophosidids, such as Platyophrya; and (3) that merotelokinetal stomatogenesis is an apomorphic character of colpodids, such as Colpoda, Bresslaua, and Pseudoplatyophrya. These predictions of relationships within the class Colpodea were investigated by determining the complete small subunit
rRNA gene sequences for the colpodid Bresslaua vorax, the grossglockneriid Pseudoplatyophrya nana, and the cyrtolophosidid Platyophrya vorax and a partial sequence for the bryometopid Bryometopus sphagni. These sequences were combined with the previously published complete SSrRNA sequences for the colpodid Colpoda inflata and the bursariomorphid Bursaria truncatella. The affiliations were assessed using both distance matrix and maximum-parsimony analyses. The tree topologies for the class
Colpodea were identical in all analyses, with bootstrap support for bifurcations always exceeding 60%. The results suggest
the following. (1) Since the clade including Bryometopus and its sister taxon, Bursaria, is never basal, the kreyellid silver-line system evolved later in colpodean phylogeny and does not separate bryometopids
from all other colpodeans. (2) Since Platyophrya is always the sister taxon to the other five genera, there is a fundamental phylogenetic significance for its macro–micronuclear
complex. (3) Since the colpodids, Colpoda, Bresslaua, and Pseudoplatyophrya, always group in one clade, merotelokinetal stomatogenesis appears to be a derived character state.
Received: 30 June 1998 / Accepted: 3 December 1998 相似文献
17.
Phylogenetic relationships of annelids,molluscs, and arthropods evidenced from molecules and morphology 总被引:10,自引:0,他引:10
Chang Bae Kim Seung Yeo Moon Stuart R. Gelder Won Kim 《Journal of molecular evolution》1996,43(3):207-215
Annelids and arthropods have long been considered each other's closest relatives, as evidenced by similarities in their segmented
body plans. An alternative view, more recently advocated by investigators who have examined partial 18S ribosomal RNA data,
proposes that annelids, molluscs, and certain other minor phyla with trochophore larva stages share a more recent common ancestor
with one another than any do with arthropods. The two hypotheses are mutually exclusive in explaining spiralian relationships.
Cladistic analysis of morphological data does not reveal phylogentic relationships among major spiralian taxa but does suggest
monophyly for both the annelids and molluscs. Distance and maximum-likelihood analyses of 18S rRNA gene sequences from major
spiralian taxa suggest a sister relationship between annelids and molluscs and provide a clear resolution within the major
groups of the spiralians. The parsimonious tree based on molecular data, however, indicates a sister relationship of the Annelida
and Bivalvia, and an earlier divergence of the Gastropoda than the Annelida–Bivalvia clade. To test further hypotheses on
the phylogenetic relationships among annelids, molluscs, and arthropods, and the ingroup relationships within the major spiralian
taxa, we combine the molecular and morphological data sets and subject the combined data matrix to parsimony analysis. The
resulting tree suggests that the molluscs and annelids form a monophyletic lineage and unites the molluscan taxa to a monophyletic
group. Therefore, the result supports the Eutrochozoa hypothesis and the monophyly of molluscs, and indicates early acquisition
of segmented body plans in arthropods.
Received: 25 September 1995 / Accepted: 15 March 1996 相似文献
18.
Satoshi Yamagishi Masanao Honda Kazuhiro Eguchi Russel Thorstrom 《Journal of molecular evolution》2001,53(1):39-46
Phylogenetic relationships of the family Vangidae and representatives of several other passeriform families were inferred
from 882 base positions of mitochondrial DNA sequences of 12S and 16S rRNA genes. Results indicated the monophyly of the Vangidae,
which includes the genus Tylas, hitherto often placed in the family Pycnonotidae. Our results also revealed the Malagasy endemic Newtonia, a genus never previously assigned to the Vangidae, to be a member of this family. These results suggest the occurrence of
an extensive in situ radiation of this family within Madagascar, and that the extant high diversity of this family is not the result of multiple
colonizations from outside. The extremely high morphological and ecological diversification of the family seems to have been
enhanced through the use and ultimate occupancy of vacant niches in this island.
Received: 8 September 2000 / Accepted: 13 February 2001 相似文献
19.
Eukaryotic vesicular transport requires the recognition of membranes through specific protein complexes. The heterotetrameric
adaptor protein complexes 1, 2, and 3 (AP1/2/3) are composed of two large, one small, and one medium adaptin subunit. We isolated
and characterized the cDNA for Arabidopsisγ-adaptin and performed a phylogenetic analysis of all adaptin subunits (proteins) in the context of all known homologous
proteins. This analysis revealed (i) that the large subunits of AP1/2/3 are homologous and (ii) two subunits of the heptameric
coatomer I (COPI) complex belong to this gene family. In addition, all small subunits and the aminoterminal domain of the
medium subunits of the heterotetramers are homologous to each other; this also holds for two corresponding subunits of the
COPI complex. AP1/2/3 and a substructure (heterotetrameric, F-COPI subcomplex) of the heptameric COPI had a common ancestral
complex (called pre-F-COPI). Since all large and all small/medium subunits share sequence similarity, the ancestor of this
complex is inferred to have been a heterodimer composed of one large and one small subunit. The situation encountered today
is the result of successive rounds of coordinated gene duplications of both the large and the small/medium subunits, with
F-COPI being the first that separated from the ancestral pre-F-COPI.
Received: 1 October 1998 / Accepted: 4 January 1999 相似文献
20.
基于28S rDNA序列的鞘藻目系统发育研究 总被引:3,自引:3,他引:0
作者进行了较广泛的样品采集,通过实验分离纯化培养得到多个鞘藻目种类的株系,并采用PCR技术新获得鞘藻目2属8个种类的部分28S rDNA序列,连同GenBank中的另两条序列,分析的物种涵盖了鞘藻目中的每个属。通过比较分析绿藻纲中包括此10条序列的共36个种类的同一基因序列,并选取Trebouxiophyceae中的椭圆小球藻(Chlorella ellipsoidea)和Fusochloris perforata作外类群,运用多种方法构建分子系统树,包括邻接法(Neighbor-Joining)、最大简约法(Maximum Parsimony)和Bayesian方法。3种方法所得的结果非常相似,在形态上就在整个绿藻中界限分明的鞘藻目从分子水平上再次证明为单系起源的类群;构建的系统发育树还在一定程度上表明毛鞘藻属处于鞘藻目内三个属中较分离的位置,而枝鞘藻属与鞘藻属植物并无明显界限。 相似文献