Rickettsial Infection in Ticks Collected from Road-Killed Wild Animals in Rio de Janeiro, Brazil

During 2008D2010, ticks were collected from road-killed wild animals within the Serra dos Orgaos National Park area in the state of Rio de Janeiro, Brazil. In total, 193 tick specimens were collected, including Amblyomma dubitatum Neumann and Amblyomma cajennense (F.) from four Hydrochoerus hydrochaeris (L.), Amblyomma calcaratum Neumann and A. cajennense from four Tamandua tetradactyla (L.), Amblyomma aureolatum (Pallas) and A. cajennense from five Cerdocyon thous L., Amblyomma longirostre (Koch) from one Sphiggurus villosus (Cuvier), Amblyomma varium Koch from three Bradypus variegatus Schinz, and A. cajennense from one Buteogallus meridionalis (Latham). Molecular analyses based on polymerase chain reaction targeting two rickettsial genes (gltA and ompA) on tick DNA extracts showed that 70.6% (12/17) of the A. dubitatum adult ticks, and all Amblyomma sp. nymphal pools collected from capybaras were shown to contain rickettsial DNA, which after DNA sequencing, revealed to be 100% identical to the recently identified Rickettsia sp. strain Pampulha from A. dubitatum ticks collected in the state of Minas Gerais, Brazil. Phylogenetic analysis with concatenated sequences (gltA-ompA) showed that our sequence from A. dubitatum ticks, referred to Rickettsia sp. strain Serra dos Orgaos, segregated under 99% bootstrap support in a same cluster with Old World rickettsiae, namely R. tamurae, R. monacensis, and Rickettsia sp. strain 774e. Because A. dubitatum is known to bite humans, the potential role of Rickettsia sp. strain Serra dos Orgaos as human pathogen must be taken into account, because both R. tamurae and R. monacencis have been reported infecting human beings.

Cutaneous and Mucocutaneous Leishmaniasis

Tegumentary leishmaniases are caused by approximately 15 species of protozoa of the genus Leishmania. They prevail in tropical and subtropical areas of the Old and New World but human mobility also makes them a medical problem in nonendemic areas. Clinical manifestations may comprise cutaneous and mucocutaneous forms that may be localized, disseminated, or diffuse in distribution and may differ in Old and New World leishmaniases. Diagnosis and treatment vary according to the clinical manifestations, geographic area, and Leishmania species involved. This article highlights the diversity and complexity of tegumentary leishmaniases, which are worsened by human immunodeficiency virus/Leishmania coinfection.

Polyphyly of the hawk genera Leucopternis and Buteogallus (Aves, Accipitridae): multiple habitat shifts during the Neotropical buteonine diversification

Abstract Background The family Accipitridae (hawks, eagles and Old World vultures) represents a large radiation of predatory birds with an almost global distribution, although most species of this family occur in the Neotropics. Despite great morphological and ecological diversity, the evolutionary relationships in the family have been poorly explored at all taxonomic levels. Using sequences from four mitochondrial genes (12S, ATP8, ATP6, and ND6), we reconstructed the phylogeny of the Neotropical forest hawk genus Leucopternis and most of the allied genera of Neotropical buteonines. Our goals were to infer the evolutionary relationships among species of Leucopternis, estimate their relationships to other buteonine genera, evaluate the phylogenetic significance of the white and black plumage patterns common to most Leucopternis species, and assess general patterns of diversification of the group with respect to species' affiliations with Neotropical regions and habitats. Results Our molecular phylogeny for the genus Leucopternis and its allies disagrees sharply with traditional taxonomic arrangements for the group, and we present new hypotheses of relationships for a number of species. The mtDNA phylogenetic trees derived from analysis of the combined data posit a polyphyletic relationship among species of Leucopternis, Buteogallus and Buteo. Three highly supported clades containing Leucopternis species were recovered in our phylogenetic reconstructions. The first clade consisted of the sister pairs L. lacernulatus and Buteogallus meridionalis, and Buteogallus urubitinga and Harpyhaliaetus coronatus, in addition to L. schistaceus and L. plumbeus. The second clade included the sister pair Leucopternis albicollis and L. occidentalis as well as L. polionotus. The third lineage comprised the sister pair L. melanops and L. kuhli, in addition to L. semiplumbeus and Buteo buteo. According to our results, the white and black plumage patterns have evolved at least twice in the group. Furthermore, species found to the east and west of the Andes (cis-Andean and trans-Andean, respectively) are not reciprocally monophyletic, nor are forest and non-forest species. Conclusion The polyphyly of Leucopternis, Buteogallus and Buteo establishes a lack of concordance of current Accipitridae taxonomy with the mtDNA phylogeny for the group, and points to the need for further phylogenetic analysis at all taxonomic levels in the family as also suggested by other recent analyses. Habitat shifts, as well as cis- and trans-Andean disjunctions, took place more than once during buteonine diversification in the Neotropical region. Overemphasis of the black and white plumage patterns has led to questionable conclusions regarding the relationships of Leucopternis species, and suggests more generally that plumage characters should be used with considerable caution in the taxonomic evaluation of the Accipitridae.

Strukturelle und funktionelle Untersuchungen zur Bedeutung der endogenen retroviralen Insertion HERV-K(C4) im C4-Gen des Menschen

Der Längenpolymorphismus des C4-Gens beruht auf der An- oder Abwesenheit einer 6.4 kb langen Insertion im Intron 9. Es handelt sich dabei um einen eigenständigen bisher noch nicht beschriebenen Virus-Typ, der alle Sequenzmerkmale der Familie der humanen endogenen Retroviren (HERV) trägt und zu den HERV-K Viren gehört. Der Provirus wurde als HERV-K(C4) bezeichnet. Die Orientierung dieses retroviralen Elements ist entgegengesetzt zu der Transkriptionsrichtung des C4-Gens. Mittels RT-PCR, RNase Protection Assays und Northern-Blot Analysen konnte der Nachweis von HERV-K(C4)-Antisense mRNA-Transkripten in verschiedenen humanen Zellinien und Geweben erbracht werden. Die retroviralen Transkripte schlossen am 5'- und 3'-Ende Sequenzen des C4-Exon 9 und Exon 10 ein, so daß diese wahrscheinlich "readthrough" Transkripte darstellen, die durch einen 5' des LTR2 gelegenen Promotor initiiert oder im Zusammenhang mit der C4-Expression transkribiert und reguliert werden. Weiterhin konnten insgesamt 4 HERV-K(C4)-mRNA Spezies, einschließlich einer Vollängen-RNA detektiert werden. Die drei subgenomischen mRNAs werden vermutlich durch einfaches und mehrfaches Spleißen generiert. Die quantitative Analyse in verschiedenen humanen Zellinien ergab, daß HERV-K(C4) durchschnittlich mit einer Kopienanzahl zwischen ca.1 bis 100 Transkripten in einer Zelle vorkommt, so daß es sich um low abundance mRNAs handelt. Mittels eines Reportergen-System konnte eine Aktivität des LTR2-Promotors in der Sense-Orientierung des Retrovirus nachgewiesen werden, die nach Stimulation mit IFN- signifikant abnahm. Ein humanes Modell-Systems wurde etabliert, um die Theorie einer Antisense-Abwehr gegen exogene Retroviren in HepG2-Zellen zu überprüfen. Die Theorie basiert auf dem Nachweis von HERV-K(C4)-Antisense-Transkripten, die über eine Heteroduplexbildung mit der Sense-mRNA von verwandten, infektiösen Retroviren eine mögliche Blockierung deren Translation erwirken könnten. Es konnte eine signifikante Abnahme der retroviralen Expression von bis zu 45% nach steigenden Dosen an IFN- in HepG2-Zellen nachgewiesen werden. Der funktionell aktive 3'-LTR-Sense Promotor sowie der Nachweis von HERV-K(C4)-Antisense Transkripten sprechen für die bedeutende Rolle von HERV-K(C4) bei der Genregulation und Schutz gegen exogene Retroviren, wodurch eine Selektion stattgefunden hat.

Ornithophily in the genus Salvia L. (Lamiaceae)

This dissertation presents for the first time a survey of bird pollinated (ornithophilous) Salvia species. Within the approximately 1000 species of the worldwide distributed genus roughly 20% (186 spp.) are bird pollinated. Excepting four species in the Old World (South Africa and Madagascar), ornithophilous species are restricted to the New World where they represent about one third of the species. They occur mainly in higher altitudes (1500-3000m) and usually grow as shrubs or perennial herbs (97%). The bilabiate to tubular flowers are often red (at least 49%), averaging 35mm (7-130mm) in length and produce a large to medium volume of nectar with rather low sugar concentration. Pollination by sunbirds and white-eyes is documented in a South African species, and that by hummingbirds in 16 species of the New World (USA, Mexico, Guatemala and Bolivia). Beside pollinator observations, the functionality of the staminal levers, the process of pollen transfer and the fitting between flowers and birds are tested by inserting museum skins and metal rods into fresh flowers. The most surprising result is the finding of two different main pollen transfer mechanisms. In at least 54% of the species an active staminal lever mechanism enables pollen deposition on the birds body. This is illustrated in detail in the South African S. lanceolata at which birds were observed to release the lever mechanism and became dusted with pollen. In contrast, the lever mechanism in about 35% of the New World species is reduced in different ways. Pollen transfer by inactive ‘levers’ is demonstrated in detail in S. haenkei in Bolivia, at which four pollinating hummingbird species could be observed. The tubular corolla forced the birds in a specific position, thereby causing pollen transfer from the exserted pollen-sacs to the birds body. With respect to the floral diversity and systematic affiliation of the species, parallel evolution of ornithophily and lever reduction is likely. Considering that bird pollinated species might have derived from bee pollinated species and that the staminal levers have become secondarily inactive, it is concluded that the shift in pollinators induced phenotypic changes even disabling such a sophisticated structure as the staminal lever mechanism.

Vergleichende computergestützte funktionsmorphologische Analyse an Molaren cercopithecoider Primaten

Die Analyse funktioneller Zusammenhänge zwischen Ernährung und Zahnmorphologie ist ein wichtiger Aspekt primatologischer und paläontologischer Forschung. Als überdauernder Teil des Verdauungssystems geben Zähne die bestmöglichen Hinweise auf die Ernährungsstrategien (ausgestorbener) Arten und eine Fülle weiterer Informationen. Aufgrund dessen ist es für die wissenschaftliche Arbeit von größter Bedeutung, die Zähne so detailliert und exakt wie möglich in ihrer gesamten Struktur zu erfassen. Bisher wurden zumeist zweidimensionale Parameter verwendet, um die komplexe Kronenmorphologie von Primatenmolaren vergleichend zu untersuchen. Die vorliegende Arbeit hatte das Ziel, Zähne verschiedener Arten von Altweltaffen mittels computerbasierter Methoden dreidimensional zu erfassen und neue Parameter zu definieren, mit denen die Form dieser Zähne objektiv erfasst und funktionell interpretiert werden kann. Mit einem Oberflächen-Scanner wurden die Gebisse einer Stichprobe von insgesamt 48 Primaten von fünf verschiedenen Arten eingescannt und mit Bildverarbeitungsmethoden so bearbeitet, dass dreidimensionale digitale Modelle einzelner Backenzähne zur Analyse vorlagen. Es wurden dabei sowohl Arten ausgewählt, die eine für ihre Gattung typische Ernährungsweise besitzen - also Frugivorie bei den Cercopithecinen und Folivorie bei den Colobinen - als auch solche, die eine davon abweichende Alimentation bevorzugen. Alle Altweltaffen haben sehr ähnliche Molaren. Colobinen haben jedoch höhere und spitzere Zahnhöcker, dünneren Zahnschmelz und scheinen ihre Zähne weniger stark abzukauen als die Meerkatzen. Diese Beobachtungen konnten mit Hilfe der neuen Parameter quantifiziert werden. Aus der 3D-Oberfläche und der Grundfläche der Zähne wurde ein Index gebildet, der die Stärke des Oberflächenreliefs angibt. Dieser Index hat bei Colobinen deutlich höhere Werte als bei Cercopithecinen, auch bei Zähnen, die schon stark abgekaut sind. Die Steilheit der Höcker und ihre Ausrichtung wurden außerdem gemessen. Auch diese Winkelmessungen bestätigten das Bild. Je höher der Blätteranteil an der Ernährung ist, desto höher sind die Indexwerte und umso steiler sind die Höcker. Besonders wichtig war es, dies auch für abgekaute Zähne zu bestätigen, die bisher nicht in funktionelle Analysen miteinbezogen wurden. Die Ausrichtung der Höckerseiten gibt Hinweise auf die Kaubewegung, die zum effizienten Zerkleinern der Nahrung notwendig ist. Die Ausrichtung der Höcker der Colobinen deutet darauf hin, dass diese Primaten flache, gleitende Kaubewegungen machen, bei denen die hohen Höcker aneinander vorbei scheren. Dies ist sinnvoll zum Zerschneiden von faserreicher Nahrung wie Blättern. Cercopithecinen scheinen ihre Backenzähne eher wie Mörser und Stößel zu verwenden, um Früchte und Samen zu zerquetschen und zu zermahlen. Je nachdem, was neben der hauptsächlichen Nahrung noch gekaut wird, unterscheiden sich die Arten graduell. Anders als bisher vermutet wurde, konnte gezeigt werden, dass Colobinen trotz des dünnen Zahnschmelzes ihre Zähne weniger stark abkauen und weniger Dentin freigelegt wird. Dies gibt eindeutige Hinweise auf die Unterschiede in der mechanischen Belastung, die während des Kauvorgangs auf die Zähne wirkt, und lässt sich gut mit der Ernährung der Arten in Zusammenhang bringen. Anhand dieser modellhaften Beobachtungen können in Zukunft ausgestorbene Arten hinsichtlich ihrer Ernährungsweise mit 3D-Techniken untersucht werden.

Comparative genomics and phylogenetics of the vertebrate CYP3 family

CYP3A verstoffwechselt mehr als 50% aller gegenwärtig in der Therapie eingesetzten Wirkstoffe, die häufig an klinisch relevanten Arzneimitttel-Wechselwirkungen beteiligt sind. Das Verständnis über die Bedeutung und die Regulation von einzelnen CYP3A Genen in der Pharmakologie und Physiologie ist unvollständig. Wir untersuchten die Evolution des CYP3 Genlokus über einen Zeitraum von 450 Millionen Jahre mittels genomischer Sequenzen von 16 Tierarten. Neue CYP3 Unterfamilien (CYP3B, C und D) entstanden über eine beschleunigte Evolution aus CYP3A Vorstufen von Clupeocephala Spezies. Ausgeprägte funktionelle Unterschiede traten zwischen CYP3A in Säugern und Clupeocephala CYP3 auf. Alle amnioten CYP3A Gene entwickelten sich aus zwei CYP3A Urgenen. Aufgrund der Entstehung von Säugern mit Plazenta ging eines von ihnen verloren während das andere eine neue genomische Umgebung infolge einer Translokation erlangte. In Primaten unterzog sich CYP3A mit mehreren Genduplikationen, Deletionen, Pseudogenisierung und Genkonversionen einer raschen evolutionären Veränderung. Die Entwicklung von CYP3A in Schmalnasenaffen (Alte Welt Affen, große Menschenaffen und Menschen) unterschieden sich wesentlich von Neue Welt Primaten (z.B. gewöhnlichen Krallenaffen) und Feuchtnasenaffen (z.B. Galago). Stellvertretend für die CYP3A Protein-codierende Sequenz entdeckten wir zwei frühe Episoden von besonders starker positiver Selektion: (1) auf CYP3A7 in der frühen hominoiden Evolution, welche im fetalen Zeitraum von einer Einschränkung der hepatischen Expression begleitet war, und (2) auf humanes CYP3A4 im Anschluss an die Teilung der Abstammungslinie in Schimpansen und Mensch. In Übereinstimmung mit diesen Befunden beeinflussen drei von vier positiv ausgewählten Aminosäuren, die in früheren biochemischen CYP3A Studien untersucht wurden, die Aktivität und Regioselektivität. Es ist somit naheliegend, dass CYP3A7 und CYP3A4 katalytische Funktionen erworben haben können, die besonders wichtig waren für die Evolution von Hominoiden und Menschen. Die Charakterisierung von CYP3A Promotoren in Primaten zeigte eine Anreicherung von ER6 Elementen in CYP3A Promotoren von Primaten und einen Trend in Richtung Erhöhung der ER6 Enstehung entlang den Abstammungslinien, die zu humanen und Schimpansen CYP3A4 führten. Die steigende Anzahl an ER6 Elementen kann durch die ausgeprägte CYP3A4 Induzierbarkeit und Expressionsvariabilität im Menschen verursacht sein.

An autochthonous case of cutaneous bovine leishmaniasis in Switzerland

The present case report describes a novel etiological agent of cutaneous leishmaniasis that appears for the first time in a cow. A similar agent had recently been described as causing autochthonous infections in horses of Germany and Switzerland. The infection in the cow was initially diagnosed upon clinical and immunohistological findings. Subsequent comparative sequence analysis of diagnostic PCR products from the internal transcribed spacer 1 (ITS1) of ssrRNA classified the respective isolate as neither Old World nor New World Leishmania species, but yielded complete identity of the analysed sequence with the above mentioned horse cases and 98% identity to Leishmania sp. siamensis, an organism recently identified in a visceral leishmaniasis patient from Thailand. The potential transmitting vectors for all these cases have not yet been identified. Future investigations will have to elucidate the veterinary-epidemiological relevance of this etiological agent, as well as biological parameters such as transmission mode and geographical origin and distribution.

Brown Capuchins (Cebus apella) Exhibit Self-Control on a Delay of Gratification Food Exchange Task When Food Options Differ Qualitatively

Self-control allows an individual to obtain a more preferred outcome by forgoing an immediate interest. Self-control is an advanced cognitive process because it involves the ability to weigh the costs and benefits of impulsive versus restrained behavior, determine the consequences of such behavior, and make decisions based on the most advantageous course of action. Self-control has been thoroughly explored in Old World primates, but less so in New World monkeys. There are many ways to test self-control abilities in non-human primates, including exchange tasks in which an animal must forgo an immediate, less preferred reward to receive a delayed, more preferred reward. I examined the self-control abilities of six capuchin monkeys using a task in which a monkey was given a less preferred food and was required to wait a delay interval to trade the fully intact less preferred food for a qualitatively higher, more preferred food. Partially eaten pieces of the less preferred food were not rewarded, and delay intervals increased on an individual basis based on performance. All six monkeys were successful in inhibiting impulsivity and trading a less preferred food for a more preferred food at the end of a delay interval. The maximum duration each subject postponed gratification instead of responding impulsively was considered their delay tolerance. This study was the first to show that monkeys could inhibit impulsivity in a delay of gratification food exchange task in which the immediate and delayed food options differed qualitatively and a partially eaten less preferred food was not rewarded with the more preferred food at the end of a delay interval. These results show that New World monkeys possess advanced cognitive abilities similar to those of Old World primates.

The evolutionary diversification of parrots supports a taxon pulse model with multiple trans-oceanic dispersal events and local radiations

Vicariance is thought to have played a major role in the evolution of modern parrots. However, as the relationships especially of the African taxa remained mostly unresolved, it has been difficult to draw firm conclusions about the roles of dispersal and vicariance. Our analyses using the broadest taxon sampling of old world parrots ever based on 3219 bp of three nuclear genes revealed well-resolved and congruent phylogenetic hypotheses. Agapornis of Africa and Madagascar was found to be the sister group to Loriculus of Australasia and Indo-Malayasia and together they clustered with the Australasian Loriinae, Cyclopsittacini and Melopsittacus. Poicephalus and Psittacus from mainland Africa formed the sister group Of the Neotropical Arini and Coracopsis from Madagascar and adjacent islands may be the closest relative of Psittrichas from New Guinea. These biogeographic relationships are best explained by independent colonization of the African continent via trans-oceanic dispersal from Australasia and Antarctica in the Paleogene following what may have been vicariance events in the late Cretaceous and/or early Paleogene. Our data support a taxon pulse model for the diversification of parrots whereby trans-oceanic dispersal played a more important role than previously thought and was the prerequisite for range expansion into new continents. (C) 2009 Elsevier Inc. All rights reserved

Occurrence of Leishmania sp. in cutaneous lesions of horses in Central Europe

The present report describes a novel etiological agent of cutaneous leishmaniasis in horses that, at least for some cases, sporadically appeared as autochthonous infections in geographically distant regions of Germany and Switzerland. The infection was initially diagnosed upon clinical and immunohistological findings. Subsequent comparative sequence analysis of diagnostic PCR products from the internal transcribed spacer 1 (ITS1) of ssrRNA classified the respective isolates as neither Old World nor New World Leishmania species. However, four isolates subjected to molecular analyses all exhibited a close phylogenetic relationship to Leishmania sp. siamensis, an organism recently identified in a visceral leishmaniasis patient from Thailand. Future investigations will demonstrate if this form of leishmaniasis represents an emerging, and perhaps zoonotic, disease of European, or even global, importance.

Histamine reduces flash sensitivity of on ganglion cells in the primate retina.

PURPOSE. In Old World primates, the retina receives input from histaminergic neurons in the posterior hypothalamus. They are a subset of the neurons that project throughout the central nervous system and fire maximally during the day. The contribution of these neurons to vision, was examined by applying histamine to a dark-adapted, superfused baboon eye cup preparation while making extracellular recordings from peripheral retinal ganglion cells. METHODS. The stimuli were 5-ms, 560-nm, weak, full-field flashes in the low scotopic range. Ganglion cells with sustained and transient ON responses and two cell types with OFF responses were distinguished; their responses were recorded with a 16-channel microelectrode array. RESULTS. Low micromolar doses of histamine decreased the rate of maintained firing and the light sensitivity of ON ganglion cells. Both sustained and transient ON cells responded similarly to histamine. There were no statistically significant effects of histamine in a more limited study of OFF ganglion cells. The response latencies of ON cells were approximately 5 ms slower, on average, when histamine was present. Histamine also reduced the signal-to-noise ratio of ON cells, particularly in those cells with a histamine-induced increase in maintained activity. CONCLUSIONS. A major action of histamine released from retinopetal axons under dark-adapted conditions, when rod signals dominate the response, is to reduce the sensitivity of ON ganglion cells to light flashes. These findings may relate to reports that humans are less sensitive to light stimuli in the scotopic range during the day, when histamine release in the retina is expected to be at its maximum.

Is paromomycin an effective and safe treatment against cutaneous leishmaniasis? A meta-analysis of 14 randomized controlled trials.

BACKGROUND: High cost, poor compliance, and systemic toxicity have limited the use of pentavalent antimony compounds (SbV), the treatment of choice for cutaneous leishmaniasis (CL). Paromomycin (PR) has been developed as an alternative to SbV, but existing data are conflicting. METHODOLOGY/PRINCIPAL FINDINGS: We searched PubMed, Scopus, and Cochrane Central Register of Controlled Trials, without language restriction, through August 2007, to identify randomized controlled trials that compared the efficacy or safety between PR and placebo or SbV. Primary outcome was clinical cure, defined as complete healing, disappearance, or reepithelialization of all lesions. Data were extracted independently by two investigators, and pooled using a random-effects model. Fourteen trials including 1,221 patients were included. In placebo-controlled trials, topical PR appeared to have therapeutic activity against the old world and new world CL, with increased local reactions, when used with methylbenzethonium chloride (MBCL) compared to when used alone (risk ratio [RR] for clinical cure, 2.58 versus 1.01: RR for local reactions, 1.60 versus 1.07). In SbV-controlled trials, the efficacy of topical PR was not significantly different from that of intralesional SbV in the old world CL (RR, 0.70; 95% confidence interval, 0.26-1.89), whereas topical PR was inferior to parenteral SbV in treating the new world CL (0.67; 0.54-0.82). No significant difference in efficacy was found between parenteral PR and parenteral SbV in the new world CL (0.88; 0.56-1.38). Systemic side effects were fewer with topical or parenteral PR than parenteral SbV. CONCLUSIONS/SIGNIFICANCE: Topical PR with MBCL could be a therapeutic alternative to SbV in selected cases of the old world CL. Development of new formulations with better efficacy and tolerability remains to be an area of future research.

Molecular Phylogenetics of Mole Crabs (Hippidae : Emerita)

Mole crabs of the genus Emerita (Family Hippidae) inhabit many of the temperate and tropical sandy beaches of the world. The nine described species of this genus are rarely sympatric, and most are endemic to broad biogeographic regions. The phylogenetic relationships among the species have not yet been investigated. Based on presumed morphological synapomorphics, it has been suggested that the species inhabiting the New World constitute a monophyletic group, as do the species inhabiting the Old World, The relationships within the New World species were previously studied using sequence data from Cytochrome Oxidase I and 16S rRNA mitochondrial genes; the results strongly suggested that one of the species, Emerita analoga, was very divergent from the other taxa examined. This observation prompted uncertainty about monophyly of the New World species. The goal of the present study was to elucidate the relationships among the species within the genus Emerita. Partial sequences for the mitochondrial COI and 16S rRNA genes for all nine species of the genus (and several outgroups) were examined. Phylogenetic analyses suggest that E. analoga is closer to the Old World taxa than to the other New World species; thus the New World Emerita species do not constitute a monophyletic group.

Long distance dispersal shaped patterns of human genetic diversity in Eurasia

Most previous attempts at reconstructing the past history of human populations did not explicitly take geography into account, or considered very simple scenarios of migration and ignored environmental information. However, it is likely that the Last Glacial Maximum (LGM) affected the demography and the range of many species, including our own. Moreover, long-distance dispersal (LDD) may have been an important component of human migrations, allowing fast colonization of new territories and preserving high levels of genetic diversity. Here, we use a high-quality microsatellite dataset genotyped in 22 populations to estimate the posterior probabilities of several scenarios for the settlement of the Old World by modern humans. We considered models ranging from a simple spatial expansion to others including LDD and a LGM-induced range contraction, as well as Neolithic demographic expansions. We find that scenarios with LDD are much better supported by data than models without LDD. Nevertheless, we show evidence that LDD events to empty habitats were strongly prevented during the settlement of Eurasia. This unexpected absence of LDD ahead of the colonization wave front could have been caused by an Allee effect, either due to intrinsic causes such as an inbreeding depression built during the expansion, or to extrinsic causes such as direct competition with archaic humans. Overall, our results suggest only a relatively limited effect of the LGM-contraction on current patterns of human diversity. This is in clear contrast with the major role of LDD migrations, which have potentially contributed to the intermingled genetic structure of Eurasian populations.