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1.
Zootaxa ; 4564(1): zootaxa.4564.1.7, 2019 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-31716520

RESUMO

Adopting the name Canis dingo for the Dingo to explicitly denote a species-level taxon separate from other canids was suggested by Crowther et al.  (2014) as a means to eliminate taxonomic instability and contention. However, Jackson et al.  (2017), using standard taxonomic and nomenclatural approaches and principles, called instead for continued use of the nomen C. familiaris for all domestic dogs and their derivatives, including the Dingo. (This name, C. familiaris, is applied to all dogs that derive from the domesticated version of the Gray Wolf, Canis lupus, based on nomenclatural convention.) The primary reasons for this call by Jackson et al.  (2017) were: (1) a lack of evidence to show that recognizing multiple species amongst the dog, including the Dingo and New Guinea Singing Dog, was necessary taxonomically, and (2) the principle of nomenclatural priority (the name familiaris Linnaeus, 1758, antedates dingo Meyer, 1793). Overwhelming current evidence from archaeology and genomics indicates that the Dingo is of recent origin in Australia and shares immediate ancestry with other domestic dogs as evidenced by patterns of genetic and morphological variation. Accordingly, for Smith et al.  (2019) to recognise Canis dingo as a distinct species, the onus was on them to overturn current interpretations of available archaeological, genomic, and morphological datasets and instead show that Dingoes have a deeply divergent evolutionary history that distinguishes them from other named forms of Canis (including C. lupus and its domesticated version, C. familiaris). A recent paper by Koepfli et al.  (2015) demonstrates exactly how this can be done in a compelling way within the genus Canis-by demonstrating deep evolutionary divergence between taxa, on the order of hundreds of thousands of years, using data from multiple genetic systems. Smith et al.  (2019) have not done this; instead they have misrepresented the content and conclusions of Jackson et al.  (2017), and contributed extraneous arguments that are not relevant to taxonomic decisions. Here we dissect Smith et al.  (2019), identifying misrepresentations, to show that ecological, behavioural and morphological evidence is insufficient to recognise Dingoes as a separate species from other domestic dogs. We reiterate: the correct binomial name for the taxon derived from Gray Wolves (C. lupus) by passive and active domestication, including Dingoes and other domestic dogs, is Canis familiaris. We are strongly sympathetic to arguments about the historical, ecological, cultural, or other significance of the Dingo, but these are issues that will have to be considered outside of the more narrow scope of taxonomy and nomenclature.


Assuntos
Lobos , Animais , Austrália , Cães , Nova Guiné
2.
Proc Natl Acad Sci U S A ; 116(38): 19019-19024, 2019 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-31481609

RESUMO

A recent study of mammoth subfossil remains has demonstrated the potential of using relatively low-coverage high-throughput DNA sequencing to genetically sex specimens, revealing a strong male-biased sex ratio [P. Pecnerová et al., Curr. Biol. 27, 3505-3510.e3 (2017)]. Similar patterns were predicted for steppe bison, based on their analogous female herd-based structure. We genetically sexed subfossil remains of 186 Holarctic bison (Bison spp.), and also 91 brown bears (Ursus arctos), which are not female herd-based, and found that ∼75% of both groups were male, very close to the ratio observed in mammoths (72%). This large deviation from a 1:1 ratio was unexpected, but we found no evidence for sex differences with respect to DNA preservation, sample age, material type, or overall spatial distribution. We further examined ratios of male and female specimens from 4 large museum mammal collections and found a strong male bias, observable in almost all mammalian orders. We suggest that, in mammals at least, 1) wider male geographic ranges can lead to considerably increased chances of detection in fossil studies, and 2) sexual dimorphic behavior or appearance can facilitate a considerable sex bias in fossil and modern collections, on a previously unacknowledged scale. This finding has major implications for a wide range of studies of fossil and museum material.

3.
Proc Natl Acad Sci U S A ; 116(31): 15327-15332, 2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-31300536

RESUMO

The dispersal of anatomically modern human populations out of Africa and across much of the rest of the world around 55 to 50 thousand years before present (ka) is recorded genetically by the multiple hominin groups they met and interbred with along the way, including the Neandertals and Denisovans. The signatures of these introgression events remain preserved in the genomes of modern-day populations, and provide a powerful record of the sequence and timing of these early migrations, with Asia proving a particularly complex area. At least 3 different hominin groups appear to have been involved in Asia, of which only the Denisovans are currently known. Several interbreeding events are inferred to have taken place east of Wallace's Line, consistent with archaeological evidence of widespread and early hominin presence in the area. However, archaeological and fossil evidence indicates archaic hominins had not spread as far as the Sahul continent (New Guinea, Australia, and Tasmania), where recent genetic evidence remains enigmatic.

4.
Biosci Rep ; 39(7)2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31273060

RESUMO

Intracellular lipid-binding proteins (iLBPs) of the fatty acid-binding protein (FABP) family of animals transport, mainly fatty acids or retinoids, are confined to the cytosol and have highly similar 3D structures. In contrast, nematodes possess fatty acid-binding proteins (nemFABPs) that are secreted into the perivitelline fluid surrounding their developing embryos. We report structures of As-p18, a nemFABP of the large intestinal roundworm Ascaris suum, with ligand bound, determined using X-ray crystallography and nuclear magnetic resonance spectroscopy. In common with other FABPs, As-p18 comprises a ten ß-strand barrel capped by two short α-helices, with the carboxylate head group of oleate tethered in the interior of the protein. However, As-p18 exhibits two distinctive longer loops amongst ß-strands not previously seen in a FABP. One of these is adjacent to the presumed ligand entry portal, so it may help to target the protein for efficient loading or unloading of ligand. The second, larger loop is at the opposite end of the molecule and has no equivalent in any iLBP structure yet determined. As-p18 preferentially binds a single 18-carbon fatty acid ligand in its central cavity but in an orientation that differs from iLBPs. The unusual structural features of nemFABPs may relate to resourcing of developing embryos of nematodes.

5.
Elife ; 82019 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-31223116

RESUMO

Modern microorganisms growing in fossils provide major challenges for researchers trying to detect ancient molecules in the same fossils.

6.
Mol Ecol Resour ; 19(4): 982-996, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30887686

RESUMO

Bacteria are not only ubiquitous on earth but can also be incredibly diverse within clean laboratories and reagents. The presence of both living and dead bacteria in laboratory environments and reagents is especially problematic when examining samples with low endogenous content (e.g., skin swabs, tissue biopsies, ice, water, degraded forensic samples or ancient material), where contaminants can outnumber endogenous microorganisms within samples. The contribution of contaminants within high-throughput studies remains poorly understood because of the relatively low number of contaminant surveys. Here, we examined 144 negative control samples (extraction blank and no-template amplification controls) collected in both typical molecular laboratories and an ultraclean ancient DNA laboratory over 5 years to characterize long-term contaminant diversity. We additionally compared the contaminant content within a home-made silica-based extraction method, commonly used to analyse low endogenous content samples, with a widely used commercial DNA extraction kit. The contaminant taxonomic profile of the ultraclean ancient DNA laboratory was unique compared to modern molecular biology laboratories, and changed over time according to researcher, month and season. The commercial kit also contained higher microbial diversity and several human-associated taxa in comparison to the home-made silica extraction protocol. We recommend a minimum of two strategies to reduce the impacts of laboratory contaminants within low-biomass metagenomic studies: (a) extraction blank controls should be included and sequenced with every batch of extractions and (b) the contributions of laboratory contamination should be assessed and reported in each high-throughput metagenomic study.


Assuntos
Contaminação por DNA , Erros de Diagnóstico , Metagenômica/métodos , Biologia Molecular/métodos
7.
Mol Ecol ; 28(10): 2476-2485, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30793442

RESUMO

Microalgal bloom events can cause major ecosystem disturbances, devastate local marine economies, and endanger public health. Therefore, detecting and monitoring harmful microalgal taxa is essential to ensure effective risk management in waterways used for fisheries, aquaculture, recreational activity, and shipping. To fully understand the current status and future direction of algal bloom distributions, we need to know how populations and ecosystems have changed over time. This baseline knowledge is critical for predicting ecosystem responses to future anthropogenic change and will assist in the future management of coastal ecosystems. We explore a NGS metabarcoding approach to rapidly identify potentially harmful microalgal taxa in 63 historic and modern Australian marine port and ballast tank sediment samples. The results provide a record of past microalgal distribution and important baseline data that can be used to assess the efficacy of shipping guidelines, nutrient pollution mitigation, and predict the impact of climate change. Critically, eDNA surveys of archived sediments were able to detect harmful algal taxa that do not produce microscopic fossils, such as Chattonella, Heterosigma, Karlodinium, and Noctiluca. Our data suggest a potential increase in Australian harmful microalgal taxa over the past 30 years, and confirm ship ballast tanks as key dispersal vectors. These molecular mapping tools will assist in the creation of policies aimed at reducing the global increase and spread of harmful algal taxa and help prevent economic and public-health problems caused by harmful algal blooms.

8.
Mol Biol Evol ; 36(4): 784-797, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30722030

RESUMO

The emergence of islands has been linked to spectacular radiations of diverse organisms. Although penguins spend much of their lives at sea, they rely on land for nesting, and a high proportion of extant species are endemic to geologically young islands. Islands may thus have been crucial to the evolutionary diversification of penguins. We test this hypothesis using a fossil-calibrated phylogeny of mitochondrial genomes (mitogenomes) from all extant and recently extinct penguin taxa. Our temporal analysis demonstrates that numerous recent island-endemic penguin taxa diverged following the formation of their islands during the Plio-Pleistocene, including the Galápagos (Galápagos Islands), northern rockhopper (Gough Island), erect-crested (Antipodes Islands), Snares crested (Snares) and royal (Macquarie Island) penguins. Our analysis also reveals two new recently extinct island-endemic penguin taxa from New Zealand's Chatham Islands: Eudyptes warhami sp. nov. and a dwarf subspecies of the yellow-eyed penguin, Megadyptes antipodes richdalei ssp. nov. Eudyptes warhami diverged from the Antipodes Islands erect-crested penguin between 1.1 and 2.5 Ma, shortly after the emergence of the Chatham Islands (∼3 Ma). This new finding of recently evolved taxa on this young archipelago provides further evidence that the radiation of penguins over the last 5 Ma has been linked to island emergence. Mitogenomic analyses of all penguin species, and the discovery of two new extinct penguin taxa, highlight the importance of island formation in the diversification of penguins, as well as the extent to which anthropogenic extinctions have affected island-endemic taxa across the Southern Hemisphere's isolated archipelagos.


Assuntos
Especiação Genética , Genoma Mitocondrial , Ilhas , Spheniscidae/genética , Animais , Fósseis , Nova Zelândia , Filogeografia
9.
Mol Ecol ; 28(10): 2636-2652, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30723959

RESUMO

Marine environments face acute pressures from human impacts, often resulting in substantial changes in community structure. On the inshore Great Barrier Reef (GBR), palaeoecological studies show the collapse of the previously dominant coral Acropora from the impacts of degraded water quality associated with European colonization. Even more dramatic impacts can result in the replacement of corals by fleshy macroalgae on modern reefs, but their past distribution is unknown because they leave no fossil record. Here, we apply DNA metabarcoding and high-throughput sequencing of the 18S rDNA gene on palaeoenvironmental DNA (aeDNA) derived from sediment cores at two sites on Pandora Reef (GBR), to enhance palaeoecological studies by incorporating key soft-bodied taxa, including macroalgae. We compared temporal trends in this aeDNA record with those of coral genera derived from macrofossils. Multivariate analysis of 12 eukaryotic groups from the aeDNA community showed wide variability over the past 750 years. The occurrence of brown macroalgae was negatively correlated only with the dominant coral at both sites. The occurrence of coralline and green macroalgae was positively correlated with only the dominant coral at one of the sites, where we also observed a significant association between the whole coral community and the occurrence of each of the three macroalgae groups. Our results demonstrate that reef sediments can provide a valuable archive for understanding the past distribution and occurrence of important soft-bodied reef dwellers. Combining information from fossils and aeDNA provides an enhanced understanding of temporal changes of reefs ecosystems at decadal to millennial timescales.

10.
PLoS One ; 14(2): e0209499, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30716066

RESUMO

Hybridization capture with in-solution oligonucleotide probes has quickly become the preferred method for enriching specific DNA loci from degraded or ancient samples prior to high-throughput sequencing (HTS). Several companies synthesize sets of probes for in-solution hybridization capture, but these commercial reagents are usually expensive. Methods for economical in-house probe synthesis have been described, but they do not directly address one of the major advantages of commercially synthesised probes: that probe sequences matching many species can be synthesised in parallel and pooled. The ability to make "phylogenetically diverse" probes increases the cost-effectiveness of commercial probe sets, as they can be used across multiple projects (or for projects involving multiple species). However, it is labour-intensive to replicate this with in-house methods, as template molecules must first be generated for each species of interest. While it has been observed that probes can be used to enrich for phylogenetically distant targets, the ability of this effect to compensate for the lack of phylogenetically diverse probes in in-house synthesised probe sets has not been tested. In this study, we present a refined protocol for in-house RNA probe synthesis and evaluated the ability of probes generated using this method from a single species to successfully enrich for the target locus in phylogenetically distant species. We demonstrated that probes synthesized using long-range PCR products from a placental mammal mitochondrion (Bison spp.) could be used to enrich for mitochondrial DNA in birds and marsupials (but not plants). Importantly, our results were obtained for approximately a third of the cost of similar commercially available reagents.

12.
Nat Ecol Evol ; 3(1): 31-38, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30478308

RESUMO

Understanding extinction events requires an unbiased record of the chronology and ecology of victims and survivors. The rhinoceros Elasmotherium sibiricum, known as the 'Siberian unicorn', was believed to have gone extinct around 200,000 years ago-well before the late Quaternary megafaunal extinction event. However, no absolute dating, genetic analysis or quantitative ecological assessment of this species has been undertaken. Here, we show, by accelerator mass spectrometry radiocarbon dating of 23 individuals, including cross-validation by compound-specific analysis, that E. sibiricum survived in Eastern Europe and Central Asia until at least 39,000 years ago, corroborating a wave of megafaunal turnover before the Last Glacial Maximum in Eurasia, in addition to the better-known late-glacial event. Stable isotope data indicate a dry steppe niche for E. sibiricum and, together with morphology, a highly specialized diet that probably contributed to its extinction. We further demonstrate, with DNA sequencing data, a very deep phylogenetic split between the subfamilies Elasmotheriinae and Rhinocerotinae that includes all the living rhinoceroses, settling a debate based on fossil evidence and confirming that the two lineages had diverged by the Eocene. As the last surviving member of the Elasmotheriinae, the demise of the 'Siberian unicorn' marked the extinction of this subfamily.


Assuntos
Extinção Biológica , Perissodáctilos , Animais , Osso e Ossos/química , Isótopos de Carbono/análise , DNA/análise , Evolução Molecular , Isótopos de Nitrogênio/análise , Perissodáctilos/genética , Filogenia
13.
Syst Biol ; 68(3): 520-537, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30481358

RESUMO

Combined "total evidence" analysis of molecular and morphological data offers the opportunity to objectively merge fossils into the tree of life, and challenges the primacy of solely DNA based phylogenetic and dating inference, even among modern taxa. To investigate the relative utility of DNA, morphology, and total evidence for evolutionary inference, we sequenced the first near-complete mitochondrial genomes from extinct Australian megafauna: a 40-50 thousand year old giant short-faced kangaroo (Simosthenurus occidentalis) and giant wallaby (Protemnodon anak). We analyzed the ancient DNA and fossil data alongside comparable data from extant species to infer phylogeny, divergence times, and ancestral body mass among macropods (kangaroos and wallabies). Our results confirm a close relationship between Protemnodon and the iconic kangaroo genus complex "Macropus", and unite the giant Simothenurus with the hare-sized Lagostrophus fasciatus (banded hare-wallaby), suggesting that the latter is the closest living link to the once diverse sthenurine kangaroo radiation. We find that large body size evolved multiple times among kangaroos, coincident with expansion of open woodland habitats beginning in the Late Miocene. In addition, our results suggest that morphological data mislead macropod phylogeny reconstruction and in turn can distort total evidence estimation of divergence dates. However, a novel result with potentially broad application is that the accuracy and precision of reconstructing ancestral body mass was improved by tracing body mass on morphological branch lengths. This is likely due to positive allometric correlation between morphological and body size variation-a relationship that may be masked or even misleadingly inverted with the temporal or molecular branch lengths that typically underpin ancestral body size reconstruction. Our study supports complementary roles for DNA and morphology in evolutionary inference, and opens a new window into the evolution of Australia's unique marsupial fauna.


Assuntos
DNA/genética , Fósseis/anatomia & histologia , Macropodidae/classificação , Filogenia , Animais , Classificação , DNA Antigo , Macropodidae/anatomia & histologia , Macropodidae/genética
14.
Trends Microbiol ; 27(2): 105-117, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30497919

RESUMO

Next-generation sequencing approaches in microbiome research have allowed surveys of microbial communities, their genomes, and their functions with higher sensitivity than ever before. However, this sensitivity is a double-edged sword because these tools also efficiently detect contaminant DNA and cross-contamination, which can confound the interpretation of microbiome data. Therefore, there is an urgent need to integrate key controls into microbiome research to improve the integrity of microbiome studies. Here, we review how contaminant DNA and cross-contamination arise within microbiome studies and discuss their negative impacts, especially during the analysis of low microbial biomass samples. We then identify several key measures that researchers can implement to reduce the impact of contaminant DNA and cross-contamination during microbiome research. We put forward a set of minimal experimental criteria, the 'RIDE' checklist, to improve the validity of future low microbial biomass research.


Assuntos
Biomassa , Contaminação por DNA , Microbiota/genética , DNA Bacteriano/análise , DNA Bacteriano/genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Metagenômica , Técnicas Microbiológicas/métodos , Técnicas Microbiológicas/normas , Reprodutibilidade dos Testes , Manejo de Espécimes
15.
Cell ; 175(5): 1185-1197.e22, 2018 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-30415837

RESUMO

We report genome-wide ancient DNA from 49 individuals forming four parallel time transects in Belize, Brazil, the Central Andes, and the Southern Cone, each dating to at least ∼9,000 years ago. The common ancestral population radiated rapidly from just one of the two early branches that contributed to Native Americans today. We document two previously unappreciated streams of gene flow between North and South America. One affected the Central Andes by ∼4,200 years ago, while the other explains an affinity between the oldest North American genome associated with the Clovis culture and the oldest Central and South Americans from Chile, Brazil, and Belize. However, this was not the primary source for later South Americans, as the other ancient individuals derive from lineages without specific affinity to the Clovis-associated genome, suggesting a population replacement that began at least 9,000 years ago and was followed by substantial population continuity in multiple regions.


Assuntos
Genética Populacional/história , Genoma Humano , América Central , DNA Antigo/análise , DNA Mitocondrial/genética , Fluxo Gênico , História Antiga , Humanos , Modelos Teóricos , América do Sul
16.
Mol Phylogenet Evol ; 129: 70-76, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30121342

RESUMO

The musk ox (Ovibos moschatus) is the only surviving member of a group of Pleistocene North American musk ox genera (Praeovibos, Ovibos, Bootherium, Euceratherium, and Soergelia) whose taxonomy is uncertain. The helmeted musk ox (Bootherium bombifrons) and the woodland musk ox (Symbos cavifrons) have been synonymised as male and female forms of a single Nearctic species found from Alaska, in the north, to Texas, in the south. However, this reclassification has not been tested using molecular data, despite the potential to use ancient DNA to examine these late Pleistocene taxa. In the present study, we sequenced mitochondrial genomes from seven subfossil musk ox specimens (originally identified as Bootherium and/or Symbos), allowing us to evaluate the identity of these muskoxen, explore their phylogeography, and estimate the timeline for their evolution. We also used nuclear genomic data to determine the sex of six of our seven samples. Ultimately, our molecular data support the synonymisation of the North American muskoxen Bootherium and Symbos.


Assuntos
Fósseis , Ruminantes/anatomia & histologia , Ruminantes/genética , Alaska , Animais , Teorema de Bayes , DNA Antigo , DNA Mitocondrial/genética , Feminino , Genoma Mitocondrial , Masculino , Filogenia , Texas
17.
Proc Natl Acad Sci U S A ; 115(34): 8482-8490, 2018 08 21.
Artigo em Inglês | MEDLINE | ID: mdl-30082377

RESUMO

Anatomically modern humans (Homo sapiens, AMH) began spreading across Eurasia from Africa and adjacent Southwest Asia about 50,000-55,000 years ago (ca 50-55 ka). Some have argued that human genetic, fossil, and archaeological data indicate one or more prior dispersals, possibly as early as 120 ka. A recently reported age estimate of 65 ka for Madjedbebe, an archaeological site in northern Sahul (Pleistocene Australia-New Guinea), if correct, offers what might be the strongest support yet presented for a pre-55-ka African AMH exodus. We review evidence for AMH arrival on an arc spanning South China through Sahul and then evaluate data from Madjedbebe. We find that an age estimate of >50 ka for this site is unlikely to be valid. While AMH may have moved far beyond Africa well before 50-55 ka, data from the region of interest offered in support of this idea are not compelling.


Assuntos
Migração Humana/história , África , Arqueologia , Ásia , História Antiga , Humanos
18.
Am J Phys Anthropol ; 167(2): 423-437, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30159882

RESUMO

Nearly all Indigenous populations today suffer from worse health than their non-Indigenous counterparts, and despite interventions against known factors, this health "gap" has not improved. The human microbiome-the beneficial, diverse microbial communities that live on and within the human body-is a crucial component in developing and maintaining normal physiological health. Disrupting this ecosystem has repercussions for microbial functionality, and thus, human health. In this article, we propose that modern-day Indigenous population health may suffer from disrupted microbial ecosystems as a consequence of historical colonialism. Colonialism may have interrupted the established relationships between the environment, traditional lifeways, and microbiomes, altering the Indigenous microbiome with detrimental health consequences.


Assuntos
Colonialismo , Disbiose/etnologia , Índios Norte-Americanos/etnologia , Microbiota/fisiologia , Saúde Pública , Dieta/etnologia , Humanos , Mudança Social
19.
ACS Med Chem Lett ; 9(7): 761-767, 2018 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-30034615

RESUMO

The emergence and evolution of new immunological cancer therapies has sparked a rapidly growing interest in discovering novel pathways to treat cancer. Toward this aim, a novel series of pyrrolidine derivatives (compound 5) were identified as potent inhibitors of ERK1/2 with excellent kinase selectivity and dual mechanism of action but suffered from poor pharmacokinetics (PK). The challenge of PK was overcome by the discovery of a novel 3(S)-thiomethyl pyrrolidine analog 7. Lead optimization through focused structure-activity relationship led to the discovery of a clinical candidate MK-8353 suitable for twice daily oral dosing as a potential new cancer therapeutic.

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