Growth form and population genetic structure ofAzorella selagoon sub-Antarctic Marion Island

2008 ◽  
Vol 20 (4) ◽  
pp. 381-390 ◽  
Author(s):  
Elizabeth Mortimer ◽  
Melodie A. McGeoch ◽  
Savel R. Daniels ◽  
Bettine Jansen van Vuuren
Keyword(s):  
Sequence Variation ◽  
Growth Form ◽  
Fragment Length Polymorphism ◽  
Sequence Data ◽  
Plant Cover ◽  
Keystone Species ◽  
Growth Dynamics ◽  
Marion Island ◽  
Genetic Studies ◽  
Cushion Plant

AbstractSeven community complexes have been described across sub-Antarctic Marion Island, amongst these fellfield that comprise low plant cover dominated byAzorella selagoHook. f.Azorellais considered a keystone species since it forms nutrient rich environments for microarthropod communities and epiphytic plants. Two distinct growth forms typifyAzorella, namely discrete cushions and continuous mats. Whether these continuous mats normally consist of a single large cushion individual, or whether several individual plants merge, interdigitating to form a continuous area, remains unclear. As such, it is important to obtain some measure ofAzorellagrowth dynamics before embarking on phylogeographic studies. Previous genetic studies indicated that several microarthropod species are significantly substructured across Marion Island, but it remains unclear whether similar subdivisions characterizeAzorella. We used chloroplast sequence data (trnH-psbA) and amplified fragment length polymorphism (AFLP) to investigate these questions. No sequence variation characterized thetrnH-psbA region inAzorellaacross Marion Island. In contrast, the AFLP results indicated that anA. selagomat comprises multiple individuals. We argue that mats can be formed through at least two processes namely fragmentation, where parts of the cushion plant die off creating open areas for the establishment of different individuals and/or high density of interdigitating individuals merging to form the mat. Fragment data further indicated significant substructure forAzorellaacross Marion Island (FST = 0.101,P = 0.01) and we attribute this to past vicariance.

scholarly journals mtDNAcombine: tools to combine sequences from multiple studies

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Eleanor F. Miller ◽  
Andrea Manica
Keyword(s):  
Sequence Data ◽  
Data Extraction ◽  
Bayesian Skyline Plot ◽  
Model Organisms ◽  
Data Sets ◽  
Data Handling ◽  
Online Database ◽  
Genetic Studies ◽  
Wide Range ◽  
Existing Data

Abstract Background Today an unprecedented amount of genetic sequence data is stored in publicly available repositories. For decades now, mitochondrial DNA (mtDNA) has been the workhorse of genetic studies, and as a result, there is a large volume of mtDNA data available in these repositories for a wide range of species. Indeed, whilst whole genome sequencing is an exciting prospect for the future, for most non-model organisms’ classical markers such as mtDNA remain widely used. By compiling existing data from multiple original studies, it is possible to build powerful new datasets capable of exploring many questions in ecology, evolution and conservation biology. One key question that these data can help inform is what happened in a species’ demographic past. However, compiling data in this manner is not trivial, there are many complexities associated with data extraction, data quality and data handling. Results Here we present the mtDNAcombine package, a collection of tools developed to manage some of the major decisions associated with handling multi-study sequence data with a particular focus on preparing sequence data for Bayesian skyline plot demographic reconstructions. Conclusions There is now more genetic information available than ever before and large meta-data sets offer great opportunities to explore new and exciting avenues of research. However, compiling multi-study datasets still remains a technically challenging prospect. The mtDNAcombine package provides a pipeline to streamline the process of downloading, curating, and analysing sequence data, guiding the process of compiling data sets from the online database GenBank.

A variable minisatellite sequence in the chloroplast genome of Sorbus L. (Rosaceae: Maloideae)

Genome ◽  
2002 ◽  
Vol 45 (3) ◽  
pp. 570-576 ◽  
Author(s):  
R Andrew King ◽  
Colin Ferris
Keyword(s):  
Restriction Fragment Length Polymorphism ◽  
Chloroplast Genome ◽  
Length Polymorphism ◽  
Sequence Variation ◽  
Fragment Length Polymorphism ◽  
Rflp Analysis ◽  
Chloroplast Microsatellites ◽  
Sorbus Aucuparia ◽  
Pcr Product ◽  
Restriction Fragment Length

The chloroplast genome is now known to be more variable than was once thought. Reports of RFLP (restriction fragment length polymorphism) and sequence variation, as well as variation in chloroplast microsatellites, are common. Here, data are presented on the variability of a minisatellite sequence in the chloroplast genome of Sorbus species. RFLP analysis of a PCR product comprising the region between the trnM and rbcL genes of nine Sorbus species identified seven size variants. Sequencing revealed the observed size polymorphism to be due to differences in the number of copies of an imperfect 9-bp motif. A more intensive survey of the variability of the minisatellite was undertaken in populations of Sorbus aucuparia. The potential uses of such regions in chloroplast DNA are discussed and a possible mechanism for the evolution of the minisatellite is presented.Key words: atpE, homoplasy, microsatellite, rowan, VNTR.

scholarly journals Multi-Omics Study of Keystone Species in a Cystic Fibrosis Microbiome

2021 ◽  
Vol 22 (21) ◽  
pp. 12050
Author(s):  
Cynthia B. Silveira ◽  
Ana G. Cobián-Güemes ◽  
Carla Uranga ◽  
Jonathon L. Baker ◽  
Anna Edlund ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Lung Function ◽  
Sequence Data ◽  
Anaerobic Bacteria ◽  
Keystone Species ◽  
Clinical Diagnostics ◽  
Epifluorescence Microscopy ◽  
Fermentation Products ◽  
Degrading Bacteria

Ecological networking and in vitro studies predict that anaerobic, mucus-degrading bacteria are keystone species in cystic fibrosis (CF) microbiomes. The metabolic byproducts from these bacteria facilitate the colonization and growth of CF pathogens like Pseudomonas aeruginosa. Here, a multi-omics study informed the control of putative anaerobic keystone species during a transition in antibiotic therapy of a CF patient. A quantitative metagenomics approach combining sequence data with epifluorescence microscopy showed that during periods of rapid lung function loss, the patient’s lung microbiome was dominated by the anaerobic, mucus-degrading bacteria belonging to Streptococcus, Veillonella, and Prevotella genera. Untargeted metabolomics and community cultures identified high rates of fermentation in these sputa, with the accumulation of lactic acid, citric acid, and acetic acid. P. aeruginosa utilized these fermentation products for growth, as indicated by quantitative transcriptomics data. Transcription levels of P. aeruginosa genes for the utilization of fermentation products were proportional to the abundance of anaerobic bacteria. Clindamycin therapy targeting Gram-positive anaerobes rapidly suppressed anaerobic bacteria and the accumulation of fermentation products. Clindamycin also lowered the abundance and transcription of P. aeruginosa, even though this patient’s strain was resistant to this antibiotic. The treatment stabilized the patient’s lung function and improved respiratory health for two months, lengthening by a factor of four the between-hospitalization time for this patient. Killing anaerobes indirectly limited the growth of P. aeruginosa by disrupting the cross-feeding of fermentation products. This case study supports the hypothesis that facultative anaerobes operated as keystone species in this CF microbiome. Personalized multi-omics may become a viable approach for routine clinical diagnostics in the future, providing critical information to inform treatment decisions.

scholarly journals Temporal signal and the phylodynamic threshold of SARS-CoV-2

2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Sebastian Duchene ◽  
Leo Featherstone ◽  
Melina Haritopoulou-Sinanidou ◽  
Andrew Rambaut ◽  
Philippe Lemey ◽  
...  
Keyword(s):  
Time Scales ◽  
Sequence Variation ◽  
Evolutionary Rate ◽  
Sequence Data ◽  
Genomic Variation ◽  
Evolutionary Rates ◽  
Data Sets ◽  
Genome Sequences ◽  
First Time ◽  
Time Of Origin

Abstract The ongoing SARS-CoV-2 outbreak marks the first time that large amounts of genome sequence data have been generated and made publicly available in near real time. Early analyses of these data revealed low sequence variation, a finding that is consistent with a recently emerging outbreak, but which raises the question of whether such data are sufficiently informative for phylogenetic inferences of evolutionary rates and time scales. The phylodynamic threshold is a key concept that refers to the point in time at which sufficient molecular evolutionary change has accumulated in available genome samples to obtain robust phylodynamic estimates. For example, before the phylodynamic threshold is reached, genomic variation is so low that even large amounts of genome sequences may be insufficient to estimate the virus’s evolutionary rate and the time scale of an outbreak. We collected genome sequences of SARS-CoV-2 from public databases at eight different points in time and conducted a range of tests of temporal signal to determine if and when the phylodynamic threshold was reached, and the range of inferences that could be reliably drawn from these data. Our results indicate that by 2 February 2020, estimates of evolutionary rates and time scales had become possible. Analyses of subsequent data sets, that included between 47 and 122 genomes, converged at an evolutionary rate of about 1.1 × 10−3 subs/site/year and a time of origin of around late November 2019. Our study provides guidelines to assess the phylodynamic threshold and demonstrates that establishing this threshold constitutes a fundamental step for understanding the power and limitations of early data in outbreak genome surveillance.

scholarly journals Population Genetic Analysis of a Global Collection of Pyrenophora tritici-repentis, Causal Agent of Tan Spot of Wheat

2005 ◽  
Vol 95 (10) ◽  
pp. 1144-1150 ◽  
Author(s):  
T. L. Friesen ◽  
S. Ali ◽  
K. K. Klein ◽  
J. B. Rasmussen
Keyword(s):  
Fragment Length Polymorphism ◽  
Sequence Data ◽  
Geographic Location ◽  
Tan Spot ◽  
Grass Species ◽  
Internal Transcribed Spacer Region ◽  
Population Genetic Analysis ◽  
Pyrenophora Tritici Repentis ◽  
Worldwide Population ◽  
America South

The work presented here is the first major study to analyze the genetic diversity within the worldwide population of the economically important wheat pathogen Pyrenophora tritici-repentis. The genetic structure of field populations of P. tritici-repentis was determined using amplified fragment length polymorphism markers along with sequence data from the internal transcribed spacer region of the ribosomal DNA. Ninetyseven fungal isolates were collected from naturally infected wheat and wild grass species. The collection of 97 P. tritici-repentis isolates included races 1, 2, 3, 4, 5, ND7, and ND8 and was collected from North America, South America, and Europe. Results show no genetic grouping of fungal races nor do results indicate grouping based on geographic location indicating that the population is preferentially outcrossing in nature and that the introduction and spread of this population is either relatively recent or that there has been a constant worldwide flow of this fungus possibly by seed movement between continents.

Amplified fragment length polymorphism and mitochondrial sequence data detect genetic differentiation and relationships in endangered southwestern U.S.A. ambersnails (Oxyloma spp.)

2000 ◽  
Vol 78 (10) ◽  
pp. 1845-1854 ◽  
Author(s):  
Mark P Miller ◽  
Larry E Stevens ◽  
Joseph D Busch ◽  
Jeff A Sorensen ◽  
Paul Keim
Keyword(s):  
Length Polymorphism ◽  
Fragment Length ◽  
Population Genetic ◽  
Fragment Length Polymorphism ◽  
Sequence Data ◽  
Amplified Fragment Length Polymorphism ◽  
Group Method ◽  
Exact Test ◽  
Additional Information ◽  
Pair Group

The Kanab ambersnail (Oxyloma haydeni kanabensis) is a federally endangered mollusc currently known to reside in two locations in the southwestern U.S.A. To determine the extent of within- and between-population genetic variation of this taxon, the amplified fragment length polymorphism (AFLP) technique was used to generate 110 genetic markers among individuals sampled from the two Kanab ambersnail populations and from the only two known southwestern populations of the Niobrara ambersnail (Oxyloma haydeni haydeni) in Utah and northern Arizona. Additional information was obtained from sequence data of cytochrome b and cytochrome oxidase I gene fragments. Results suggest high levels of differentiation among populations, as evidenced through the application of UPGMA (unweighted pair-group method with arthimetic averaging) clustering, F statistics, and Fisher's exact test. Various levels of within-population genetic diversity were observed among populations. Expected heterozygosities ranged from 0.239 to 0.086 under a model assuming Hardy-Weinberg genotypic proportions and ranged from 0.205 to 0.061 under an obligate-selfing completely homozygous model. Results from cluster analyses showed that one Kanab ambersnail population and one Niobrara ambersnail population were more similar than the two Kanab ambersnail populations studied (supported by >80% of bootstrap replicates). These findings were further supported through the phylogenetic analysis of both mito chondrial gene fragments. The data suggest that taxonomic designations need revision, an act that will likely affect the protected status of some of the populations.

scholarly journals Sequence Variation inToxoplasma gondii rop17Gene among Strains from Different Hosts and Geographical Locations

2014 ◽  
Vol 2014 ◽  
pp. 1-4
Author(s):  
Nian-Zhang Zhang ◽  
Ying Xu ◽  
Si-Yang Huang ◽  
Dong-Hui Zhou ◽  
Rui-Ai Wang ◽  
...  
Keyword(s):  
Sequence Variation ◽  
High Ratio ◽  
Type I ◽  
Gene Sequences ◽  
Genetic Studies ◽  
Sequence Variations ◽  
Geographical Regions ◽  
Gene Data ◽  
Geographical Locations ◽  
Rhoptry Protein

Genetic diversity ofT. gondiiis a concern of many studies, due to the biological and epidemiological diversity of this parasite. The present study examined sequence variation in rhoptry protein 17 (ROP17) gene amongT. gondiiisolates from different hosts and geographical regions. Therop17gene was amplified and sequenced from 10T. gondiistrains, and phylogenetic relationship among theseT. gondiistrains was reconstructed using maximum parsimony (MP), neighbor-joining (NJ), and maximum likelihood (ML) analyses. The partialrop17gene sequences were 1375 bp in length and A+T contents varied from 49.45% to 50.11% among all examinedT. gondiistrains. Sequence analysis identified 33 variable nucleotide positions (2.1%), 16 of which were identified as transitions. Phylogeny reconstruction based onrop17gene data revealed two major clusters which could readily distinguish Type I and Type II strains. Analyses of sequence variations in nucleotides and amino acids among these strains revealed high ratio of nonsynonymous to synonymous polymorphisms (>1), indicating thatrop17shows signs of positive selection. This study demonstrated the existence of slightly high sequence variability in therop17gene sequences amongT. gondiistrains from different hosts and geographical regions, suggesting thatrop17gene may represent a new genetic marker for population genetic studies ofT. gondiiisolates.

Phylogeny of the genus Bryoria

2011 ◽  
Vol 43 (6) ◽  
pp. 617-638 ◽  
Author(s):  
Leena MYLLYS ◽  
Saara VELMALA ◽  
Håkon HOLIEN ◽  
Pekka HALONEN ◽  
Li-Song WANG ◽  
...  
Keyword(s):  
Growth Form ◽  
Sequence Data ◽  
Molecular Study ◽  
Morphological Characters ◽  
Ssu Rdna ◽  
Species Status ◽  
Infrageneric Classification ◽  
Rdna Sequence Data ◽  
Cladistic Analyses ◽  
Current Species

AbstractThe phylogenetic relationships of the genus Bryoria were examined using ITS, partial glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and mitochondrial SSU rDNA sequence data in addition to 20 chemical and morphological characters. This first comprehensive molecular study to assess Bryoria phylogeny includes representatives from all the traditionally recognized four sections. Combined cladistic analyses of 88 Bryoria specimens representing at least 25 species resulted in highly resolved phylogenies. Based on the results, a new infrageneric classification for the genus is proposed. Five sections are recognized, largely corresponding to the existing classification, with the addition of section Americanae. The study shows that while most species with an erect growth-form are clearly monophyletic, current species status of many pendent taxa can be questioned.

scholarly journals Speciation and Domestication in Maize and Its Wild Relatives: Evidence From the Globulin-1 Gene

Genetics ◽  
1998 ◽  
Vol 150 (2) ◽  
pp. 863-872 ◽  
Author(s):  
Holly Hilton ◽  
Brandon S Gaut
Keyword(s):  
Dna Sequences ◽  
Sequence Variation ◽  
Common Ancestor ◽  
Seed Storage Protein ◽  
Sequence Data ◽  
Seed Storage ◽  
Neutral Evolution ◽  
Recent Event ◽  
Intermediate Size ◽  
Founder Event

Abstract The grass genus Zea contains the domesticate maize and several wild taxa indigenous to Central and South America. Here we study the genetic consequences of speciation and domestication in this group by sampling DNA sequences from four taxa—maize (Zea mays ssp. mays), its wild progenitor (Z. mays ssp. parviglumis), a more distant species within the genus (Z. luxurians), and a representative of the sister genus (Tripsacum dactyloides). We sampled a total of 26 sequences from the glb1 locus, which encodes a nonessential seed storage protein. Within the Zea taxa sampled, the progenitor to maize contains the most sequence diversity. Maize contains 60% of the level of genetic diversity of its progenitor, and Z. luxurians contains even less diversity (32% of the level of diversity of Z. mays ssp. parviglumis). Sequence variation within the glb1 locus is consistent with neutral evolution in all four taxa. The glb1 data were combined with adh1 data from a previous study to make inferences about the population genetic histories of these taxa. Comparisons of sequence data between the two morphologically similar wild Zea taxa indicate that the species diverged ∼700,000 years ago from a common ancestor of intermediate size to their present populations. Conversely, the domestication of maize was a recent event that could have been based on a very small number of founding individuals. Maize retained a substantial proportion of the genetic variation of its progenitor through this founder event, but diverged rapidly in morphology.

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