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Highly conserved D-loop-like nuclear mitochondrial sequences (Numts) in tiger (Panthera tigris).

Using oligonucleotide primers designed to match hypervariable segments I (HVS-1) of Panthera tigris mitochondrial DNA (mtDNA), we amplified two different PCR products (500 bp and 287 bp) in the tiger (Panthera tigris), but got only one PCR product (287 bp) in the leopard (Panthera pardus). Sequence analyses indicated that the sequence of 287 bp was a D-loop-like nuclear mitochondrial sequence (Numts), indicating a nuclear transfer that occurred approximately 4.8-17 million years ago in the tiger and 4.6-16 million years ago in the leopard. Although the mtDNA D-loop sequence has a rapid rate of evolution, the 287-bp Numts are highly conserved; they are nearly identical in tiger subspecies and only 1.742% different between tiger and leopard. Thus, such sequences represent molecular 'fossils' that can shed light on evolution of the mitochondrial genome and may be the most appropriate outgroup for phylogenetic analysis. This is also proved by comparing the phylogenetic trees reconstructed using the D-loop sequence of snow leopard and the 287-bp Numts as outgroup.

Animals↗

Genomic blot hybridization as a tool of phylogenetic analysis: evolutionary divergence in the genus Drosophila.

Comparative, quantitative Southern analysis of genomic DNA, using single-copy sequence probes, potentially is valuable for phylogenetic analysis. We have examined 27 Drosophila species, belonging to two subgenera, seven species groups, and ten subgroups, using a variety of cloned and characterized probes: twelve cloned sequences from D. melanogaster, two from D. pseudoobscura, and two from D. grimshawi. The data are generally congruent with accepted phylogenetic relationships in Drosophila, and confirm or clarify some previously uncertain relationships. The potential and limitations of the method are discussed.

Animals↗

Comparative analysis of chloroplast genomes in ten holly (Ilex) species: insights into phylogenetics and genome evolution.

In order to clarify the chloroplast genomes and structural features of ten Ilex species and provide insights into the phylogeny and genome evolution of the genus Ilex, we conducted a comparative analysis of chloroplast genomes using bioinformatics methods. The chloroplast genomes of ten Ilex species were obtained, and their structural features and variations were compared. The results indicated that all chloroplast genomes in the genus Ilex exhibit a double-stranded circular structure, with sizes ranging from 157,356 to 158,018 bp, showing minimal differences in size. The chloroplast genomes of the ten Ilex species have a relatively conservative gene count, with a total of 134 to 135 genes, including 88 or 89 protein-coding genes, and a conserved number of 8 rRNA genes. Each chloroplast genome contains 3 to 123 SSR (Simple Sequence Repeat) sites, predominantly composed of mononucleotide and trinucleotide repeats, with no detection of pentanucleotide or hexanucleotide repeats. The variation in dispersed repeat sequences among Ilex species is minimal, with a total repeat sequence number ranging from 1 to 14, concentrated in the length range of 30 to 42 base pairs. The expansion and contraction of chloroplast genome boundaries among Ilex species are relatively stable, with only minor variations observed in individual species. Variations in non-coding regions are more pronounced than those in coding regions, with the variability in the Large Single Copy region (LSC) being the highest, while the variability in the Inverted Repeat region A (IRa) is the lowest. The divergence time among Ilex species was estimated using the MCMC-tree module, revealing the evolutionary relationships among these species, their common ancestors, and their differentiation throughout the evolutionary process. The research findings provide a valuable reference for the systematic study and molecular marker development of Ilex plants.

Genome, Chloroplast↗

A phylogenetic analysis of the family Dermatophilaceae.

The comparative analysis of the 16S ribosomal ribonucleic acid (rRNA) of Geodermatophilus obscurus DSM 43060 and Dermatophilus congolensis DSM 43037 revealed that these members of the family Dermatophilaceae were only remotely related. While G. obscurus represented an individual and separate line of descent within the phylogenetically defined order Actinomycetales, D. congolensis was closely related to representatives of Arthrobacter, Micrococcus, Cellulomonas, Brevibacterium, Promicromonospora and Microbacterium.

Actinomycetales↗

Comparative 16S rRNA analysis of lake bacterioplankton reveals globally distributed phylogenetic clusters including an abundant group of actinobacteria.

In a search for cosmopolitan phylogenetic clusters of freshwater bacteria, we recovered a total of 190 full and partial 16S ribosomal DNA (rDNA) sequences from three different lakes (Lake Gossenköllesee, Austria; Lake Fuchskuhle, Germany; and Lake Baikal, Russia). The phylogenetic comparison with the currently available rDNA data set showed that our sequences fall into 16 clusters, which otherwise include bacterial rDNA sequences of primarily freshwater and soil, but not marine, origin. Six of the clusters were affiliated with the alpha, four were affiliated with the beta, and one was affiliated with the gamma subclass of the Proteobacteria; four were affiliated with the Cytophaga-Flavobacterium-Bacteroides group; and one was affiliated with the class Actinobacteria (formerly known as the high-G+C gram-positive bacteria). The latter cluster (hgcI) is monophyletic and so far includes only sequences directly retrieved from aquatic environments. Fluorescence in situ hybridization (FISH) with probes specific for the hgcI cluster showed abundances of up to 1.7 x 10(5) cells ml(-1) in Lake Gossenköllesee, with strong seasonal fluctuations, and high abundances in the two other lakes investigated. Cell size measurements revealed that Actinobacteria in Lake Gossenköllesee can account for up to 63% of the bacterioplankton biomass. A combination of phylogenetic analysis and FISH was used to reveal 16 globally distributed sequence clusters and to confirm the broad distribution, abundance, and high biomass of members of the class Actinobacteria in freshwater ecosystems.

Actinobacteria↗

Comparative analysis of seeded and vegetative biotype buffalograsses based on phylogenetic relationship using ISSRs, SSRs, RAPDs, and SRAPs.

Buffalograss [ Buchloe dactyloides (Nutt.) Englem.] is the only native grass that is being used extensively as a turfgrass in the Great Plains region. Its low-growth habit, drought resistance, and low-maintenance requirement make it attractive as a turfgrass species. Our objective was to obtain an overview on the genetic relatedness among and within seeded and vegetative biotype buffalograsses using inter-simple sequence repeats (ISSRs), random amplified polymorphic DNA (RAPDs), sequence-related amplified polymorphisms (SRAPs), and simple sequence repeats (SSRs) markers that were derived from related species (maize, pearl millet, sorghum, and sugarcane). Twenty individuals per cultivar were genotyped using 30 markers from each marker system. All buffalograss cultivars were uniquely fingerprinted by all four marker systems. Mean genetic similarities were estimated at 0.52, 0.51, 0.62, and 0.57 using SSRs, ISSRs, SRAPs, and RAPDs, respectively. Two main clusters separating the seeded-biotype from the vegetative-biotype cultivars were produced using UPGMA analysis. Further subgroupings were unequivocal. The Mantel test resulted in a very good fit (SRAP=0.92, ISSR=0.90) to good fit (RAPD=0.86, SSR=0.88) of cophenetic values. Comparing the four marker systems to each other, RAPD and SRAP similarity indices were highly correlated ( r=0.73), while Spearman's rank correlation coefficient between RAPDs and SSRs was r=0.24 and between ISSRs and SSRs was r=0.66. A genotype-assignment analytical approach might be useful for cultivar identification and property rights protection. Polymorphic SRAPs were abundant and demonstrated genetic diversity among closely related cultivars.

Analysis of Variance↗

Phylogenetic placement of the Spirosomaceae.

Comparative analysis of 16S rRNA sequences shows that the family Spirosomaceae belongs within the eubacterial phylum defined by the flavobacteria and bacteriodes. Its constituent genera, Spirosoma, Flectobacillus, and Runella form a monophyletic grouping therein. The phylogenetic assignment is based not only upon evolutionary distance analysis, but also upon sequence signatures and higher order structural synapomorphies in 16S rRNA. Another genus peripherally associated with the Spirosomaceae, Ancylobacter ("Microcyclus"), does not cluster with the flavobacteria and their relatives, but rather belongs to the alpha subdivision of the purple bacteria.

Bacteria↗

The rice kinase database. A phylogenomic database for the rice kinome.

The rice (Oryza sativa) genome contains 1,429 protein kinases, the vast majority of which have unknown functions. We created a phylogenomic database (http://rkd.ucdavis.edu) to facilitate functional analysis of this large gene family. Sequence and genomic data, including gene expression data and protein-protein interaction maps, can be displayed for each selected kinase in the context of a phylogenetic tree allowing for comparative analysis both within and between large kinase subfamilies. Interaction maps are easily accessed through links and displayed using Cytoscape, an open source software platform. Chromosomal distribution of all rice kinases can also be explored via an interactive interface.

Amino Acid Motifs↗

The chloroplast genome of Phalaenopsis aphrodite (Orchidaceae): comparative analysis of evolutionary rate with that of grasses and its phylogenetic implications.

Whether the Amborella/Amborella-Nymphaeales or the grass lineage diverged first within the angiosperms has recently been debated. Central to this issue has been focused on the artifacts that might result from sampling only grasses within the monocots. We therefore sequenced the entire chloroplast genome (cpDNA) of Phalaenopsis aphrodite, Taiwan moth orchid. The cpDNA is a circular molecule of 148,964 bp with a comparatively short single-copy region (11,543 bp) due to the unusual loss and truncation/scattered deletion of certain ndh subunits. An open reading frame, orf91, located in the complementary strand of the rrn23 was reported for the first time. A comparison of nucleotide substitutions between P. aphrodite and the grasses indicates that only the plastid expression genes have a strong positive correlation between nonsynonymous (Ka) and synonymous (Ks) substitutions per site, providing evidence for a generation time effect, mainly across these genes. Among the intron-containing protein-coding genes of the sampled monocots, the Ks of the genes are significantly correlated to transitional substitutions of their introns. We compiled a concatenated 61 protein-coding gene alignment for the available 20 cpDNAs of vascular plants and analyzed the data set using Bayesian inference, maximum parsimony, and neighbor-joining (NJ) methods. The analyses yielded robust support for the Amborella/Amborella-Nymphaeales-basal hypothesis and for the orchid and grasses together being a monophyletic group nested within the remaining angiosperms. However, the NJ analysis using Ka, the first two codon positions, or amino acid sequences, respectively, supports the monocots-basal hypothesis. We demonstrated that these conflicting angiosperm phylogenies are most probably linked to the transitional sites at all codon positions, especially at the third one where the strong base-composition bias and saturation effect take place.

DNA, Chloroplast↗

Phylogenetic approaches in comparative physiology.

Over the past two decades, comparative biological analyses have undergone profound changes with the incorporation of rigorous evolutionary perspectives and phylogenetic information. This change followed in large part from the realization that traditional methods of statistical analysis tacitly assumed independence of all observations, when in fact biological groups such as species are differentially related to each other according to their evolutionary history. New phylogenetically based analytical methods were then rapidly developed, incorporated into ;the comparative method', and applied to many physiological, biochemical, morphological and behavioral investigations. We now review the rationale for including phylogenetic information in comparative studies and briefly discuss three methods for doing this (independent contrasts, generalized least-squares models, and Monte Carlo computer simulations). We discuss when and how to use phylogenetic information in comparative studies and provide several examples in which it has been helpful, or even crucial, to a comparative analysis. We also consider some difficulties with phylogenetically based statistical methods, and of comparative approaches in general, both practical and theoretical. It is our personal opinion that the incorporation of phylogeny information into comparative studies has been highly beneficial, not only because it can improve the reliability of statistical inferences, but also because it continually emphasizes the potential importance of past evolutionary history in determining current form and function.

Computer Simulation↗

Polytene chromosome maps in four species of tsetse flies Glossina austeni, G. pallidipes, G. morsitans morsitans and G. m. submorsitans (Diptera: Glossinidae): a comparative analysis.

Photographic polytene chromosome maps from pupal trichogen cells of four tsetse species, Glossina austeni, G. pallidipes, G. morsitans morsitans and G. m. submorsitans were constructed and compared. The homology of chromosomal elements between the species was achieved by comparing banding patterns. The telomeric and subtelomeric chromosome regions were found to be identical in all species. The pericentromeric regions were found to be similar in the X chromosome and the left arm of L1 chromosome (L1L) but different in L2 chromosome and the right arm of L1 chromosome (L1R). The L2 chromosome differs by a pericentric inversion that is fixed in the three species, G. pallidipes, G. morsitans morsitans and G. m. submorsitans. Moreover, the two morsitans subspecies appeared to be homosequential and differ only by two paracentric inversions on XL and L2L arm. Although a degree of similarity was observed across the homologous chromosomes in the four species, the relative position of specific chromosome regions was different due to chromosome inversions established during their phylogeny. However, there are regions that show no apparent homology between the species, an observation that may be attributed to the considerable intra--chromosomal rearrangements that have occurred following the species divergence. The results of this comparative analysis support the current phylogenetic relationships of the genus Glossina.

Animals↗

Comparative analysis of mt LSU rRNA secondary structures of Odonates: structural variability and phylogenetic signal.

Secondary structures of the most conserved part of the mt 16S rRNA gene, domains IV and V, have been recently analysed in a comparative study. However, full secondary structures of the mt LSU rRNA molecule are published for only a few insect species. The present study presents full secondary structures of domains I, II, IV and V of Odonates and one representative of mayflies, Ephemera sp. The reconstructions are based on a comparative approach and minimal consensus structures derived from sequence alignments. The inferred structures exhibit remarkable similarities to the published Drosophila melanogaster model, which increases confidence in these structures. Structural variance within Odonates is homoplastic, and neighbour-joining trees based on tree edit distances do not correspond to any of the phylogenetically expected patterns. However, despite homoplastic quantitative structural variation, many similarities between Odonates and Ephemera sp. suggest promising character sets for higher order insect systematics that merit further investigations.

Animals↗

mILD: a tool for constructing and analyzing matrices of pairwise phylogenetic character incongruence tests.

SUMMARY: Pairwise comparisons of disagreement in phylogenetic datasets offer a powerful tool for isolating historical incongruence for closer analysis. Statistically significant phylogenetic character incongruence may reflect important differences in evolutionary history, such as horizontal gene transfer. Such testing can also be used to specify possible combinations of datasets for further phylogenetic analysis. The process of comparing multiple datasets can be very time consuming, and it is sometimes unclear how to combine data partitions given the observed patterns of incongruence. Here we present an application that automates the process of making pairwise comparisons between large numbers of phylogenetic datasets using the Incongruence Length Difference (ILD) test. The application also implements strategies for data combination based on the patterns of incongruence observed in pairwise comparisons.

Algorithms↗

A molecular genetic analysis of Eragrostis tef (Zucc.) Trotter: non-coding regions of chloroplast DNA, 18S rDNA and the transcription factor VP1.

The non-coding chloroplast DNA sequences of the trnL (UAA) intron and the trnL-trnF (GAA) intergeneric spacer (IGS), the coding sequences of nuclear 18S rDNA, and the transcription factor Vp1 of the cereal tef (Eragrostis tef (Zucc.) Trotter) were studied. No intraspecific variation was found among the 6 studied tef varieties. However, the study displayed that Eragrostis tef has a number of unique traits compared to other grasses. Phylogenetic analysis of the chloroplast DNA gave three grass clades, joining Eragrostis with sorghum and maize in one. In the analysis of the 18S rDNA sequences, the three grass species were joined in a monophyletic trichotomy in the cladogram, in which maize is the most divergent, rice the least and tef intermediate. The Vp1 is highly conserved. The Vp1 phylogeny showed that the tef Vp1-sequence is the hitherto most divergent Vp1-sequence reported from a grass.

Amino Acid Sequence↗

Phylogenetic relationships within terrestrial mites (Acari: Prostigmata, Parasitengona) inferred from comparative DNA sequence analysis of the mitochondrial cytochrome oxidase subunit I gene.

Partial DNA and amino acid sequences translated from the mitochondrial cytochrome subunit I gene (408 bp) of 17 mite species have been used for analyzing the phylogenetic relationships within the terrestrial Parasitengona (Trombidia). Due to mutational saturation of the third codon position, only first and second codon positions and amino acid sequences were analyzed, applying neighbor-joining, maximum-parsimony, and maximum-likelihood tree-building methods. The reconstructed trees revealed similar topologies of taxa; however, the phylogenetic relationships could be convincingly resolved only within several trombidioid taxa. The proposed basic relationships within the Parasitengona, in particular those of Calyptostomatoidea, Smarididae, and Erythraeidae, were poorly supported in bootstrap tests. A comparison of the presented gene tree with a phylogenetic tree based upon traditional characters revealed only few contradictions in nodes only weakly supported by morphological data. The most astonishing result is the proposed early derivative position of Microtrombidiidae within the terrestrial Parasitengona.

Animals↗

Isolation and characterization of the genomic region from Drosophila kuntzei containing the Adh and Adhr genes.

The nucleotide sequences of the Adh and Adhr genes of Drosophila kuntzei were derived from combined overlapping sequences of clones isolated from a genomic library and from cloned PCR and inverse-PCR fragments. Only a proximal promoter was detected upstream of the Adh gene, indicating that D. kuntzei Adh is regulated by a one-promoter system. Further upstream of the Adh structural gene, an adult enhancer region (AAE) was found that contains most of the regulatory sequences described for AAEs of other Drosophila species. Analysis of the ADH protein showed an amino acid change from valine to threonine in the active site at position 189 which is also found in D. funebris but is otherwise unique among Drosophila. This difference alone may be responsible for the very low ADH activity found in this species and may cause a difference in substrate usage pattern. Codon bias in Adh and Adhr was comparable and found to be very low compared with other species. Phylogenetic analysis showed that D. kuntzei is closest related to D. funebris and D. immigrans. The time of divergence between D. kuntzei and D. funebris was estimated to be 14.2-20.2 Myr and that between D. kuntzei-D. funebris and D. immigrans to be 30.8-44.0 Myr. An analysis of the genetic variation in the Adh gene and upstream sequences of four European strains showed that this gene was highly variable. Overall nucleotide diversity (pi) was 0.0139, which is two times higher than that in D. melanogaster.

Alcohol Dehydrogenase↗

A fatal case of babesiosis in Missouri: identification of another piroplasm that infects humans.

OBJECTIVE: To characterize the etiologic agents (MO1) of the first reported case of babesiosis acquired in Missouri. DESIGN: Case report, serologic testing, animal inoculations, and molecular studies. SETTING: Southeastern Missouri. PATIENT: A 73-year-old man who had had a splenectomy and had a fatal case of babesiosis. MEASUREMENTS: Serum specimens from the patient were assayed by indirect immunofluorescent antibody testing and immunoprecipitation for reactivity with antigens from various Babesia species. Whole blood obtained from the patient before treatment was inoculated into hamsters and jirds and into calves and bighorn sheep that had had splenectomy and were immunosuppressed with dexamethasone. Piroplasm-specific nuclear small-subunit ribosomal DNA was recovered from the patient's blood by using broad-range amplification with the polymerase chain reaction; a 144 base-pair region of the amplification product was sequenced; and phylogenetic analysis was done to compare MO1 with various Babesia species. RESULTS: Indirect immunofluorescent antibody testing showed that the patient's serum had strong reactivity with Babesia divergens, which causes babesiosis in cattle and humans in Europe, but that it had minimal reactivity with B. microti and WA1, which are the piroplasms previously known to cause zoonotic babesiosis in the United States. Immunoprecipitations showed that MO1 is more closely related to B. divergens than to B. canis (a canine parasite). None of the experimentally inoculated animals became demonstrably parasitemic. Phylogenetic analyses, after DNA sequencing, showed that MO1 is most closely related to B. divergens (100% similarity). CONCLUSIONS: Although MO1 is probably distinct from B. divergens, the two share morphologic, antigenic, and genetic characteristics; MO1 probably represents a Babesia species not previously recognized to have infected humans. Medical personnel should be aware that patients in the United States can have life-threatening babesiosis even though they are seronegative to B. microti and WA1 antigen.

Aged↗

Succinispira mobilis gen. nov., sp. nov., a succinate-decarboxylating anaerobic bacterium.

A succinate-decarboxylating anaerobic bacterium, designated strain 19gly1T, was previously isolated from a mixed culture growing with glycolate. The almost complete sequence of the 16S rRNA gene (1495 nt) was determined for this strain. On the basis of 16S rRNA gene sequence homology, strain 19gly1T was identified as a member of the Sporomusa sub-branch of the 'low G+C' Gram-positive bacteria. Phylogenetic analysis showed that strain 19gly1T was most closely related to Succiniclasticum ruminis, Phascolarctobacterium faecium and Acidaminococcus fermentans. The use of different algorithms, such as least-squares or neighbour-joining analyses of Jukes-Cantor pairwise distances, or maximum-parsimony or maximum-likelihood analyses of the aligned sequence data, revealed that strain 19gly1T grouped as the most deeply branching lineage of the strain 19gly1T-Succiniclasticum- Acidaminococcus-Phascolarctobacterium cluster. The phenotypic characteristics of strain 19gly1T distinguish it from members of the genera Succiniclasticum, Phascolarctobacterium and Acidaminococcus, and the phylogenetic distances inferred from comparative analysis of the 16S rDNA sequences suggest that strain 19gly1T is a representative of a new genus. Accordingly, strain 19gly1T (= DSM 6222T) is proposed as the type strain of a new species within a new genus, Succinispira mobilis gen. nov., sp. nov.

Bacteria, Anaerobic↗