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1.
Curr Biol ; 33(16): 3409-3422.e6, 2023 08 21.
Article de Anglais | MEDLINE | ID: mdl-37506702

RÉSUMÉ

Bees are the most significant pollinators of flowering plants. This partnership began ca. 120 million years ago, but the uncertainty of how and when bees spread across the planet has greatly obscured investigations of this key mutualism. We present a novel analysis of bee biogeography using extensive new genomic and fossil data to demonstrate that bees originated in Western Gondwana (Africa and South America). Bees likely originated in the Early Cretaceous, shortly before the breakup of Western Gondwana, and the early evolution of any major bee lineage is associated with either the South American or African land masses. Subsequently, bees colonized northern continents via a complex history of vicariance and dispersal. The notable early absences from large landmasses, particularly in Australia and India, have important implications for understanding the assembly of local floras and diverse modes of pollination. How bees spread around the world from their hypothesized Southern Hemisphere origin parallels the histories of numerous flowering plant clades, providing an essential step to studying the evolution of angiosperm pollination syndromes in space and time.


Sujet(s)
Fossiles , Magnoliopsida , Abeilles/génétique , Animaux , Phylogenèse , Génomique , Magnoliopsida/génétique , Amérique du Sud
2.
Am J Bot ; 108(5): 756-768, 2021 05.
Article de Anglais | MEDLINE | ID: mdl-33988869

RÉSUMÉ

PREMISE: A subset of parasitic plants bear extremely reduced features and grow nearly entirely within their hosts. Until recently, most of these endoparasites were thought to represent a single clade united by their reduced morphology. Current phylogenetic understanding contradicts this assumption and indicates these plants represent distantly related clades, thus offering an opportunity to examine convergence among plants with this life history. METHODS: We sampled species from Apodanthaceae, Cytinaceae, Mitrastemonaceae, and Rafflesiaceae spanning a range of developmental stages. To provide a broader comparative framework, Santalaceae mistletoes with a similar lifestyle were also analyzed. Microtomography and microscopy were used to analyze growth patterns and the ontogeny of host-parasite vascular connections. RESULTS: Apodanthaceae, Cytinaceae, Mitrastemonaceae, and Rafflesiaceae species demonstrated a common development characterized by late cell differentiation. These species were also observed to form direct connections to host vessels and to cause severe alterations of host xylem development. Apodanthaceae and Rafflesiaceae species were additionally observed to form sieve elements, which connect with the host phloem. Endophytic Santalaceae species demonstrated a dramatically different developmental pattern, featuring early cell differentiation and tissue organization, and little effect on host anatomy and cambial activity. CONCLUSIONS: Our results illuminate two distinct developmental trajectories in endoparasites. One involves the retention of embryonic characteristics and late connection with host vessels, as demonstrated in species of Apodanthaceae, Cytinaceae, Mitrastemonaceae, and Rafflesiaceae. The second involves tissue specialization and early connection with host xylem, as exemplified by Santalaceae species. These differences are hypothesized to be related to the absence/presence of photosynthesis in these plants.


Sujet(s)
Magnoliopsida , Gui , Phloème , Phylogenèse , Xylème
3.
Trends Psychiatry Psychother ; 42(1): 48-54, 2020.
Article de Anglais | MEDLINE | ID: mdl-32321084

RÉSUMÉ

INTRODUCTION: The opioid epidemic is a severe problem in the world, especially in the United States, where prescription opioid overdose accounts for a quarter of drug overdose deaths. OBJECTIVE: To describe psychiatrists' prescription of opioid, benzodiazepine, and buprenorphine in the United States. METHODS: We conducted a retrospective cross-sectional study of the 2016 Medicare Part D claims data and analyzed psychiatrists' prescriptions of: 1) opioids; 2) benzodiazepines, whose concurrent prescription with opioids can cause overdose death; 3) buprenorphine, a partial opioid agonist for treating opioid addiction; 4) and naltrexone microsphere, a once-monthly injectable opioid antagonist to prevent relapse to opioid dependence. Prescribers with 11 or more claims were included in the analysis. RESULTS: In Medicare Part D in 2016, there were a total of 1,131,550 prescribers accounting for 1,480,972,766 total prescriptions and 78,145,305 opioid prescriptions, including 25,528 psychiatrists (2.6% of all prescribers) accounting for 44,684,504 total prescriptions (3.0% of all prescriptions) and 131,115 opioid prescriptions (0.2% of all opioid prescriptions). Psychiatrists accounted for 17.3% of benzodiazepine, 16.3% of buprenorphine, and 33.4% of naltrexone microsphere prescriptions. The opioid prescription rate of psychiatrists was much lower than that of all prescribers (0.3 vs 5.3%). The buprenorphine prescription rate of psychiatrists was much higher than that of all prescribers (2.3 vs. 0.1%). There was a substantial geographical variation across the United States. CONCLUSIONS: The results show that, proportionally, psychiatrists have lower rates of opioid prescription and higher rates of benzodiazepine and buprenorphine prescription.


Sujet(s)
Analgésiques morphiniques/usage thérapeutique , Benzodiazépines/usage thérapeutique , Buprénorphine/usage thérapeutique , Ordonnances médicamenteuses/statistiques et données numériques , Medicare part D (USA)/statistiques et données numériques , Antagonistes narcotiques/usage thérapeutique , Types de pratiques des médecins/statistiques et données numériques , Psychiatrie/statistiques et données numériques , Adulte , Études transversales , Humains , Études rétrospectives , États-Unis
5.
Trends psychiatry psychother. (Impr.) ; 42(1): 48-54, Jan.-Mar. 2020. tab, graf
Article de Anglais | LILACS | ID: biblio-1099399

RÉSUMÉ

Abstract Introduction The opioid epidemic is a severe problem in the world, especially in the United States, where prescription opioid overdose accounts for a quarter of drug overdose deaths. Objective To describe psychiatrists' prescription of opioid, benzodiazepine, and buprenorphine in the United States. Methods We conducted a retrospective cross-sectional study of the 2016 Medicare Part D claims data and analyzed psychiatrists' prescriptions of: 1) opioids; 2) benzodiazepines, whose concurrent prescription with opioids can cause overdose death; 3) buprenorphine, a partial opioid agonist for treating opioid addiction; 4) and naltrexone microsphere, a once-monthly injectable opioid antagonist to prevent relapse to opioid dependence. Prescribers with 11 or more claims were included in the analysis. Results In Medicare Part D in 2016, there were a total of 1,131,550 prescribers accounting for 1,480,972,766 total prescriptions and 78,145,305 opioid prescriptions, including 25,528 psychiatrists (2.6% of all prescribers) accounting for 44,684,504 total prescriptions (3.0% of all prescriptions) and 131,115 opioid prescriptions (0.2% of all opioid prescriptions). Psychiatrists accounted for 17.3% of benzodiazepine, 16.3% of buprenorphine, and 33.4% of naltrexone microsphere prescriptions. The opioid prescription rate of psychiatrists was much lower than that of all prescribers (0.3 vs 5.3%). The buprenorphine prescription rate of psychiatrists was much higher than that of all prescribers (2.3 vs. 0.1%). There was a substantial geographical variation across the United States. Conclusions The results show that, proportionally, psychiatrists have lower rates of opioid prescription and higher rates of benzodiazepine and buprenorphine prescription.


Sujet(s)
Adulte , Humains , Ordonnances médicamenteuses/statistiques et données numériques , Psychiatrie/statistiques et données numériques , Benzodiazépines/usage thérapeutique , Types de pratiques des médecins/statistiques et données numériques , Buprénorphine/usage thérapeutique , Medicare part D (USA)/statistiques et données numériques , Analgésiques morphiniques/usage thérapeutique , Antagonistes narcotiques/usage thérapeutique , États-Unis , Études transversales , Études rétrospectives
6.
J Arthroplasty ; 35(6S): S37-S41, 2020 06.
Article de Anglais | MEDLINE | ID: mdl-32081502

RÉSUMÉ

BACKGROUND: In January 2018, the Center for Medicare and Medicaid Services (CMS) removed total knee arthroplasty (TKA) from the inpatient-only list. This impacted hospital reimbursement, Comprehensive Joint Replacement (CJR) bundle volumes, and bundle performance. We describe these impacts at an academic teaching hospital. METHODS: We reviewed CJR bundle data provided by CMS and internal databases to identify the shift in CJR TKA episode volume since January 2018, the impact on postacute care (PAC) utilization rates and readmissions, financial impact to the bundle, and impact on hospital reimbursement. We used data provided to CJR participants, internal hospital sources, and the Medicare Limited Data Set. RESULTS: Between 2017 and 2018, CJR TKA episodes decreased from 91 to 51 (44% reduction). Inpatient PAC utilization was significantly higher in 2018 (20% vs 8%). The 90-day readmission rates increased from 5.5% to 12.7%. Average variance to target dropped from 15% to 5%. Average CMS reimbursement for TKA at our institution in 2019 was $14,823 for inpatients and $9299 for outpatients. We experienced $930,463 in decreased reimbursement from January 2018 to September 2019 as a result of the shift from inpatient to outpatient. In addition, we expect $625,143 in decreased incentive payments as higher functioning and lower cost outpatient TKAs are excluded from CJR. CONCLUSION: Although CMS projected a minimal impact on CJR bundle participants, this has not been the case at our institution. We experienced reduced volumes, increased PAC utilization, and a substantial financial impact. We expect a similar outcome when CMS removes total hip arthroplasty from the inpatient-only list.


Sujet(s)
Arthroplastie prothétique de hanche , Arthroplastie prothétique de genou , Centres hospitaliers universitaires , Sujet âgé , Humains , Medicare (USA) , Patients en consultation externe , Soins de santé tertiaires , États-Unis
7.
J Phycol ; 54(6): 775-787, 2018 12.
Article de Anglais | MEDLINE | ID: mdl-29989670

RÉSUMÉ

Gracilariaceae has a worldwide distribution including numerous economically important species. We applied high-throughput sequencing to obtain organellar genomes (mitochondria and chloroplast) from 10 species of Gracilariaceae and, combined with published genomes, to infer phylogenies and compare genome architecture among species representing main lineages. We obtained similar topologies between chloroplast and mitochondrial genomes phylogenies. However, the chloroplast phylogeny was better resolved with full support. In this phylogeny, Melanthalia intermedia is sister to a monophyletic clade including Gracilaria and Gracilariopsis, which were both resolved as monophyletic genera. Mitochondrial and chloroplast genomes were highly conserved in gene synteny, and variation mainly occurred in regions where insertions of plasmid-derived sequences (PDS) were found. In mitochondrial genomes, PDS insertions were observed in two regions where the transcription direction changes: between the genes cob and trnL, and trnA and trnN. In chloroplast genomes, PDS insertions were in different positions, but generally found between psdD and rrs genes. Gracilariaceae is a good model system to study the impact of PDS in genome evolution due to the frequent presence of these insertions in organellar genomes. Furthermore, the bacterial leuC/leuD operon was found in chloroplast genomes of Gracilaria tenuistipitata, G. chilensis, and M. intermedia, and in extrachromosomal plasmid of G. vermiculophylla. Phylogenetic trees show two different origins of leuC/leuD: genes found in chloroplast and plasmid were placed with proteobacteria, and genes encoded in the nucleus were close to Viridiplantae and cyanobacteria.


Sujet(s)
Évolution moléculaire , Génome de chloroplaste/génétique , Génome mitochondrial/génétique , Rhodophyta/génétique , Phylogenèse , Analyse de séquence d'ADN
8.
J Arthroplasty ; 33(6): 1855-1860, 2018 06.
Article de Anglais | MEDLINE | ID: mdl-29555498

RÉSUMÉ

BACKGROUND: Acute and acute hematogenous prosthetic joint infections (PJIs) are often treated with open debridement and polyethylene exchange (ODPE) in an effort to save the prosthesis, decrease morbidity, and reduce costs. However, failure of ODPE may compromise a subsequent 2-stage treatment. The purpose of this study is to identify patient factors that impact the success of ODPE for acute and acute hematogenous PJIs. METHODS: A retrospective review examined comorbidities, preoperative laboratory values, and patient history for patients with successful and failed ODPE treatment for acute perioperative or acute hematogenous periprosthetic hip or knee joint infections. Successful treatment was defined as retaining a well-fixed implant without the need for additional surgery for a minimum of 6-month follow-up with or without lifelong oral maintenance antibiotics. RESULTS: Fifty-three of 72 patients (73.6%) underwent successful ODPE. Of the 19 failures, 14 completed 2-stage revision with one subsequent known failure for recurrent infection. Patients with a Staphylococcus aureus infection were more likely to fail ODPE (48.3% vs 11.6%, P = .0012, odds ratio 7.1, 95% confidence interval 2.3-25.3). Patients with a preoperative hematocrit ≤32.1 were also more likely to fail ODPE (55% vs 16%, P = .0013, odds ratio 6.7, 95% confidence interval 2.2-22.4). When neither risk factor was present, 97.1% of PJIs were successfully treated with ODPE. CONCLUSION: S aureus infection and preoperative hematocrit ≤32.1 are independent risk factors for ODPE failure. ODPE is a safe alternative to 2-stage revision in patients without preoperative anemia and without S aureus infection. Two-thirds of patients with a failed ODPE were successfully treated with a 2-stage reimplantation.


Sujet(s)
Anémie/complications , Arthrite infectieuse/chirurgie , Prothèse de hanche/effets indésirables , Prothèse de genou/effets indésirables , Infections dues aux prothèses/chirurgie , Sujet âgé , Antibactériens/administration et posologie , Arthrite infectieuse/complications , Arthrite infectieuse/microbiologie , Arthroplastie prothétique de genou/effets indésirables , Transfusion sanguine , Débridement , Femelle , Hématocrite , Humains , Articulation du genou/chirurgie , Mâle , Adulte d'âge moyen , Odds ratio , Polyéthylène , Infections dues aux prothèses/complications , Infections dues aux prothèses/microbiologie , Études rétrospectives , Appréciation des risques , Facteurs de risque , Infections à staphylocoques/étiologie , Staphylococcus aureus , Échec thérapeutique , Résultat thérapeutique
9.
J Phycol ; 52(6): 997-1017, 2016 12.
Article de Anglais | MEDLINE | ID: mdl-27485203

RÉSUMÉ

Species in the genus Gracilaria that display conspicuously flattened vegetative morphologies are a taxonomically challenging group of marine benthic red algae. This is a result of their species richness, morphological similarity, and broad phenotypic plasticity. Within this group, the Gracilaria domingensis complex is one of the most common, conspicuous, and morphologically variable species along the tropical western Atlantic Ocean. Previous research has identified that members of this complex belong to two distantly related clades. However, despite this increased phylogentic resolution, species delimitations within each of these clades remain unclear. Our study assessed the species diversity within this difficult complex using morphological and molecular data from three genetic markers (cox1, UPA, and rbcL). We additionally applied six single-marker species delimitation methods (SDM: ABGD, GMYCs, GMYCm, SPN, bPTP, and PTP) to rbcL, which were largely in agreement regarding species delimitation. These results, combined with our analysis of morphology, indicate that the G. domingensis complex includes seven distinct species, each of which are not all most closely related: G. cervicornis; a ressurected G. ferox; G. apiculata subsp. apiculata; a new species, Gracilaria baiana sp. nov.; G. intermedia subsp. intermedia; G. venezuelensis; and G. domingensis sensu stricto, which includes the later heterotypic synonym, G. yoneshigueana. Our study demonstrates the value of multipronged strategies, including the use of both molecular and morphological approaches, to decipher cryptic species of red algae.


Sujet(s)
Gracilaria/classification , Algue marine/classification , Protéines d'algue/génétique , Caraïbe , ADN des algues/génétique , Gracilaria/cytologie , Gracilaria/génétique , Amérique du Nord , Phylogenèse , ARN ribosomique 23S/génétique , Algue marine/cytologie , Algue marine/génétique , Analyse de séquence d'ADN , Amérique du Sud , Spécificité d'espèce
10.
New Phytol ; 210(4): 1430-42, 2016 06.
Article de Anglais | MEDLINE | ID: mdl-26990796

RÉSUMÉ

The tropical Andes of South America, the world's richest biodiversity hotspot, are home to many rapid radiations. While geological, climatic, and ecological processes collectively explain such radiations, their relative contributions are seldom examined within a single clade. We explore the contribution of these factors by applying a series of diversification models that incorporate mountain building, climate change, and trait evolution to the first dated phylogeny of Andean bellflowers (Campanulaceae: Lobelioideae). Our framework is novel for its direct incorporation of geological data on Andean uplift into a macroevolutionary model. We show that speciation and extinction are differentially influenced by abiotic factors: speciation rates rose concurrently with Andean elevation, while extinction rates decreased during global cooling. Pollination syndrome and fruit type, both biotic traits known to facilitate mutualisms, played an additional role in driving diversification. These abiotic and biotic factors resulted in one of the fastest radiations reported to date: the centropogonids, whose 550 species arose in the last 5 million yr. Our study represents a significant advance in our understanding of plant evolution in Andean cloud forests. It further highlights the power of combining phylogenetic and Earth science models to explore the interplay of geology, climate, and ecology in generating the world's biodiversity.


Sujet(s)
Biodiversité , Codonopsis/génétique , Évolution biologique , Climat , Changement climatique , Codonopsis/anatomie et histologie , Codonopsis/effets des radiations , Écologie , Fleurs/anatomie et histologie , Fleurs/génétique , Fleurs/effets des radiations , Géologie , Phylogenèse , Pollinisation , Amérique du Sud
12.
J Phycol ; 51(2): 356-66, 2015 Apr.
Article de Anglais | MEDLINE | ID: mdl-26986530

RÉSUMÉ

Gracilariaceae are mostly pantropical red algae and include ~230 species in seven genera. Infrafamilial classification of the group has long been based on reproductive characters, but previous phylogenies have shown that traditionally circumscribed groups are not monophyletic. We performed phylogenetic analyses using two plastid (universal plastid amplicon and rbcL) and one mitochondrial (cox1) loci from a greatly expanded number of taxa to better assess generic relationships and understand patterns of character distributions. Our analyses produce the most well-supported phylogeny of the family to date, and indicate that key characteristics of spermatangia and cystocarp type do not delineate genera as commonly suggested. Our results further indicate that Hydropuntia is not monophyletic. Given their morphological overlap with closely related members of Gracilaria, we propose that Hydropuntia be synonymized with the former. Our results additionally expand the known ranges of several Gracilariaceae species to include Brazil. Lastly, we demonstrate that the recently described Gracilaria yoneshigueana should be synonymized as G. domingensis based on morphological and molecular characters. These results demonstrate the utility of DNA barcoding for understanding poorly known and fragmentary materials of cryptic red algae.

13.
Front Genet ; 5: 433, 2014.
Article de Anglais | MEDLINE | ID: mdl-25566320

RÉSUMÉ

Biogeography and community ecology can mutually illuminate the formation of a regional species pool or biome. Here, we apply phylogenetic methods to a large and diverse plant clade, Malpighiaceae, to characterize the formation of its species pool in Mexico, and its occupancy of the seasonally dry tropical forest (SDTF) biome that occurs there. We find that the ~162 species of Mexican Malpighiaceae represent ~33 dispersals from South America beginning in the Eocene and continuing until the Pliocene (~46.4-3.8 Myr). Furthermore, dispersal rates between South America and Mexico show a significant six-fold increase during the mid-Miocene (~23.9 Myr). We hypothesize that this increase marked the availability of Central America as an important corridor for Neotropical plant migration. We additionally demonstrate that this high rate of dispersal contributed substantially more to the phylogenetic diversity of Malpighiaceae in Mexico than in situ diversification. Finally, we show that most lineages arrived in Mexico pre-adapted with regard to one key SDTF trait, total annual precipitation. In contrast, these lineages adapted to a second key trait, precipitation seasonality, in situ as mountain building in the region gave rise to the abiotic parameters of extant SDTF. The timing of this in situ adaptation to seasonal precipitation suggests that SDTF likely originated its modern characteristics by the late Oligocene, but was geographically more restricted until its expansion in the mid-Miocene. These results highlight the complex interplay of dispersal, adaptation, and in situ diversification in the formation of tropical biomes. Our results additionally demonstrate that these processes are not static, and their relevance can change markedly over evolutionary time. This has important implications for understanding the origin of SDTF in Mexico, but also for understanding the temporal and spatial origin of biomes and regional species pools more broadly.

14.
PLoS Pathog ; 9(10): e1003657, 2013.
Article de Anglais | MEDLINE | ID: mdl-24130481

RÉSUMÉ

Aquatic birds harbor diverse influenza A viruses and are a major viral reservoir in nature. The recent discovery of influenza viruses of a new H17N10 subtype in Central American fruit bats suggests that other New World species may similarly carry divergent influenza viruses. Using consensus degenerate RT-PCR, we identified a novel influenza A virus, designated as H18N11, in a flat-faced fruit bat (Artibeus planirostris) from Peru. Serologic studies with the recombinant H18 protein indicated that several Peruvian bat species were infected by this virus. Phylogenetic analyses demonstrate that, in some gene segments, New World bats harbor more influenza virus genetic diversity than all other mammalian and avian species combined, indicative of a long-standing host-virus association. Structural and functional analyses of the hemagglutinin and neuraminidase indicate that sialic acid is not a ligand for virus attachment nor a substrate for release, suggesting a unique mode of influenza A virus attachment and activation of membrane fusion for entry into host cells. Taken together, these findings indicate that bats constitute a potentially important and likely ancient reservoir for a diverse pool of influenza viruses.


Sujet(s)
Chiroptera/virologie , Réservoirs de maladies/virologie , Glycoprotéine hémagglutinine du virus influenza/génétique , Virus de la grippe A/génétique , Infections à Orthomyxoviridae/génétique , Phylogenèse , Animaux , Infections à Orthomyxoviridae/épidémiologie , Infections à Orthomyxoviridae/médecine vétérinaire , Pérou/épidémiologie
15.
Proc Natl Acad Sci U S A ; 109(11): 4269-74, 2012 Mar 13.
Article de Anglais | MEDLINE | ID: mdl-22371588

RÉSUMÉ

Influenza A virus reservoirs in animals have provided novel genetic elements leading to the emergence of global pandemics in humans. Most influenza A viruses circulate in waterfowl, but those that infect mammalian hosts are thought to pose the greatest risk for zoonotic spread to humans and the generation of pandemic or panzootic viruses. We have identified an influenza A virus from little yellow-shouldered bats captured at two locations in Guatemala. It is significantly divergent from known influenza A viruses. The HA of the bat virus was estimated to have diverged at roughly the same time as the known subtypes of HA and was designated as H17. The neuraminidase (NA) gene is highly divergent from all known influenza NAs, and the internal genes from the bat virus diverged from those of known influenza A viruses before the estimated divergence of the known influenza A internal gene lineages. Attempts to propagate this virus in cell cultures and chicken embryos were unsuccessful, suggesting distinct requirements compared with known influenza viruses. Despite its divergence from known influenza A viruses, the bat virus is compatible for genetic exchange with human influenza viruses in human cells, suggesting the potential capability for reassortment and contributions to new pandemic or panzootic influenza A viruses.


Sujet(s)
Chiroptera/virologie , Virus de la grippe A/génétique , Phylogenèse , Animaux , DNA-directed RNA polymerases/métabolisme , Gènes rapporteurs/génétique , Génome viral/génétique , Géographie , Guatemala , Glycoprotéine hémagglutinine du virus influenza/composition chimique , Glycoprotéine hémagglutinine du virus influenza/génétique , Humains , Données de séquences moléculaires , Sialidase/composition chimique , Sialidase/génétique , Analyse de séquence d'ADN
16.
Virology ; 396(1): 76-84, 2010 Jan 05.
Article de Anglais | MEDLINE | ID: mdl-19896684

RÉSUMÉ

A type A avian influenza (AI) virus was isolated from dead or severely ill red-winged tinamous (Rhynchotus rufescens) found in a hunting ground in April 2008 in Argentina. The subtype of A/red-winged tinamou/Argentina/MP1/2008 was determined as H1N1 by sequence analysis. The cleavage site of the viral hemagglutinin corresponded to a low pathogenic influenza virus, although the clinical presentation and pathological studies suggest that the virus was pathogenic for red-winged tinamous. Phylogenetic analysis of the viral genome suggested that while the hemagglutinin and neuraminidase genes were related to AIV from North America, the internal genes were most closely related to other South American isolates. These findings support the postulated South American phylogenetic lineage for AIV PB2, PB1, PA, M and NS genes, and suggest that the evolutionary pathways of HA and NA genes involve exchanges between the Northern and Southern hemispheres.


Sujet(s)
Oiseaux/virologie , Sous-type H1N1 du virus de la grippe A/isolement et purification , Animaux , Argentine , Séquence nucléotidique , Tests d'inhibition de l'hémagglutination , Glycoprotéine hémagglutinine du virus influenza/génétique , Sous-type H1N1 du virus de la grippe A/classification , Grippe chez les oiseaux/diagnostic , Grippe chez les oiseaux/anatomopathologie , Données de séquences moléculaires , Sialidase/génétique , Phylogenèse , RT-PCR
17.
Proc Natl Acad Sci U S A ; 99(10): 6833-7, 2002 May 14.
Article de Anglais | MEDLINE | ID: mdl-11983870

RÉSUMÉ

Explanations for biogeographic disjunctions involving South America and Africa typically invoke vicariance of western Gondwanan biotas or long distance dispersal. These hypotheses are problematical because many groups originated and diversified well after the last known connection between Africa and South America (approximately 105 million years ago), and it is unlikely that "sweepstakes" dispersal accounts for many of these disjunctions. Phylogenetic analyses of the angiosperm clade Malpighiaceae, combined with fossil evidence and molecular divergence-time estimates, suggest an alternative hypothesis to account for such distributions. We propose that Malpighiaceae originated in northern South America, and that members of several clades repeatedly migrated into North America and subsequently moved via North Atlantic land connections into the Old World during episodes starting in the Eocene, when climates supported tropical forests. This Laurasian migration route may explain many other extant lineages that exhibit western Gondwanan distributions.


Sujet(s)
Protéines d'Arabidopsis , Évolution moléculaire , Malpighiaceae/génétique , NADH dehydrogenase/génétique , Phytochrome/génétique , Protéines végétales , Séquence nucléotidique , ADN des plantes , Malpighiaceae/classification , Données de séquences moléculaires , Amérique du Nord , Phylogenèse , Amérique du Sud
18.
Buenos Aires; Panamericana; 1 ed; 1984. xxiii,972 p. ilus.
Monographie de Espagnol | BINACIS | ID: biblio-1186829
19.
Buenos Aires; Panamericana; 1984. xxv,1253 p. ilus.
Monographie de Espagnol | BINACIS | ID: biblio-1187126
20.
Buenos Aires; Panamericana; 1984. xxv,1253 p. ilus. (58473).
Monographie de Espagnol | BINACIS | ID: bin-58473
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