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1.
Proc Natl Acad Sci U S A ; 121(6): e2220392121, 2024 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-38305758

RESUMEN

Germline colonization by retroviruses results in the formation of endogenous retroviruses (ERVs). Most colonization's occurred millions of years ago. However, in the Australo-Papuan region (Australia and New Guinea), several recent germline colonization events have been discovered. The Wallace Line separates much of Southeast Asia from the Australo-Papuan region restricting faunal and pathogen dispersion. West of the Wallace Line, gibbon ape leukemia viruses (GALVs) have been isolated from captive gibbons. Two microbat species from China appear to have been infected naturally. East of Wallace's Line, the woolly monkey virus (a GALV) and the closely related koala retrovirus (KoRV) have been detected in eutherians and marsupials in the Australo-Papuan region, often vertically transmitted. The detected vertically transmitted GALV-like viruses in Australo-Papuan fauna compared to sporadic horizontal transmission in Southeast Asia and China suggest the GALV-KoRV clade originates in the former region and further models of early-stage genome colonization may be found. We screened 278 samples, seven bat and one rodent family endemic to the Australo-Papuan region and bat and rodent species found on both sides of the Wallace Line. We identified two rodents (Melomys) from Australia and Papua New Guinea and no bat species harboring GALV-like retroviruses. Melomys leucogaster from New Guinea harbored a genomically complete replication-competent retrovirus with a shared integration site among individuals. The integration was only present in some individuals of the species indicating this retrovirus is at the earliest stages of germline colonization of the Melomys genome, providing a new small wild mammal model of early-stage genome colonization.


Asunto(s)
Quirópteros , Retrovirus Endógenos , Gammaretrovirus , Marsupiales , Animales , Virus de la Leucemia del Gibón/genética , Nueva Guinea , Gammaretrovirus/genética , Murinae/genética , Marsupiales/genética , Células Germinativas
2.
Syst Biol ; 2023 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-37527840

RESUMEN

The Australian continent's size and isolation make it an ideal place for studying the accumulation and evolution of biodiversity. Long separated from the ancient supercontinent Gondwana, most of Australia's plants and animals are unique and endemic, including the continent's frogs. Australian frogs comprise a remarkable ecological and morphological diversity categorized into a small number of distantly related radiations. We present a phylogenomic hypothesis based on an exon-capture dataset that spans the main clades of Australian myobatrachoid, pelodryadid hyloid, and microhylid frogs. Our time-calibrated phylogenomic-scale phylogeny identifies great disparity in the relative ages of these groups which vary from Gondwanan relics to recent immigrants from Asia and include arguably the continent's oldest living vertebrate radiation. This age stratification provides insight into the colonization of⁠, and diversification on, the Australian continent through deep time, during periods of dramatic climatic and community changes. Contemporary Australian frog diversity highlights the adaptive capacity of anurans, particularly in response to heat and aridity, and explains why they are one of the continent's most visible faunas.

3.
PLoS Biol ; 19(6): e3001210, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-34061821

RESUMEN

Global biodiversity loss is a profound consequence of human activity. Disturbingly, biodiversity loss is greater than realized because of the unknown number of undocumented species. Conservation fundamentally relies on taxonomic recognition of species, but only a fraction of biodiversity is described. Here, we provide a new quantitative approach for prioritizing rigorous taxonomic research for conservation. We implement this approach in a highly diverse vertebrate group-Australian lizards and snakes. Of 870 species assessed, we identified 282 (32.4%) with taxonomic uncertainty, of which 17.6% likely comprise undescribed species of conservation concern. We identify 24 species in need of immediate taxonomic attention to facilitate conservation. Using a broadly applicable return-on-investment framework, we demonstrate the importance of prioritizing the fundamental work of identifying species before they are lost.


Asunto(s)
Biodiversidad , Clasificación , Investigación , Animales , Australia , Lagartos/clasificación , Serpientes/clasificación
4.
Mol Biol Evol ; 39(4)2022 04 10.
Artículo en Inglés | MEDLINE | ID: mdl-35417559

RESUMEN

Horizontal transfer (HT) of genes between multicellular animals, once thought to be extremely rare, is being more commonly detected, but its global geographic trend and transfer mechanism have not been investigated. We discovered a unique HT pattern of Bovine-B (BovB) LINE retrotransposons in vertebrates, with a bizarre transfer direction from predators (snakes) to their prey (frogs). At least 54 instances of BovB HT were detected, which we estimate to have occurred across time between 85 and 1.3 Ma. Using comprehensive transcontinental sampling, our study demonstrates that BovB HT is highly prevalent in one geographical region, Madagascar, suggesting important regional differences in the occurrence of HTs. We discovered parasite vectors that may plausibly transmit BovB and found that the proportion of BovB-positive parasites is also high in Madagascar where BovB thus might be physically transported by parasites to diverse vertebrates, potentially including humans. Remarkably, in two frog lineages, BovB HT occurred after migration from a non-HT area (Africa) to the HT hotspot (Madagascar). These results provide a novel perspective on how the prevalence of parasites influences the occurrence of HT in a region, similar to pathogens and their vectors in some endemic diseases.


Asunto(s)
Transferencia de Gen Horizontal , Parásitos , Animales , Bovinos , Geografía , Parásitos/genética , Filogenia , Conducta Predatoria , Retroelementos , Vertebrados/genética
5.
Mol Phylogenet Evol ; 189: 107934, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37769826

RESUMEN

Paleo-climatic fluctuations have driven episodic changes in species distributions, providing opportunities for populations to diverge in isolation and hybridise following secondary contact. Studies of phylogeographic diversity and patterns of gene flow across hybrid zones can provide insight into contemporary species boundaries and help to inform taxonomic and conservation inferences. Here we explore geographic diversity within the acoustically divergent yet morphologically conserved south-eastern Australian smooth frog complex and assess gene flow across a narrow hybrid zone using mitochondrial nucleotide sequences and nuclear genome-wide single nucleotide polymorphisms. Our analyses reveal the presence of an evolutionarily distinct taxon restricted to the Otway Plains and Ranges, Victoria, which forms a narrow (9-30 km wide), spatiotemporally stable (>50 years) hybrid zone with Geocrinia laevis, which we describe herein as a new species.


Asunto(s)
Anuros , ADN Mitocondrial , Animales , Filogeografía , Filogenia , Anuros/genética , Australia , Secuencia de Bases , ADN Mitocondrial/genética
6.
PLoS Genet ; 16(5): e1008769, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-32392206

RESUMEN

Polyploidy has played an important role in evolution across the tree of life but it is still unclear how polyploid lineages may persist after their initial formation. While both common and well-studied in plants, polyploidy is rare in animals and generally less understood. The Australian burrowing frog genus Neobatrachus is comprised of six diploid and three polyploid species and offers a powerful animal polyploid model system. We generated exome-capture sequence data from 87 individuals representing all nine species of Neobatrachus to investigate species-level relationships, the origin and inheritance mode of polyploid species, and the population genomic effects of polyploidy on genus-wide demography. We describe rapid speciation of diploid Neobatrachus species and show that the three independently originated polyploid species have tetrasomic or mixed inheritance. We document higher genetic diversity in tetraploids, resulting from widespread gene flow between the tetraploids, asymmetric inter-ploidy gene flow directed from sympatric diploids to tetraploids, and isolation of diploid species from each other. We also constructed models of ecologically suitable areas for each species to investigate the impact of climate on differing ploidy levels. These models suggest substantial change in suitable areas compared to past climate, which correspond to population genomic estimates of demographic histories. We propose that Neobatrachus diploids may be suffering the early genomic impacts of climate-induced habitat loss, while tetraploids appear to be avoiding this fate, possibly due to widespread gene flow. Finally, we demonstrate that Neobatrachus is an attractive model to study the effects of ploidy on the evolution of adaptation in animals.


Asunto(s)
Anuros/clasificación , Anuros/genética , Secuenciación del Exoma/métodos , Poliploidía , Animales , Australia , Ecosistema , Evolución Molecular , Flujo Génico , Especiación Genética , Filogenia , Simpatría
7.
Am Nat ; 199(2): E57-E75, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-35077279

RESUMEN

AbstractSpecies vary extensively in geographic range size and climatic niche breadth. If range limits are primarily determined by climatic factors, species with broad climatic tolerances and those that track geographically widespread climates should have large ranges. However, large ranges might increase the probability of population fragmentation and adaptive divergence, potentially decoupling climatic niche breadth and range size. Conversely, ecological generalism in large-ranged species might lead to higher gene flow across climatic transitions, increasing species' cohesion and thus decreasing genetic isolation by distance (IBD). Focusing on Australia's iconic Ctenotus lizard radiation, we ask whether species range size scales with climatic niche breadth and the degree of population isolation. To this end, we infer independently evolving operational taxonomic units (OTUs), their geographic and climatic ranges, and the strength of IBD within OTUs based on genome-wide loci from 722 individuals spanning 75 taxa. Large-ranged OTUs were common and had broader climatic niches than small-ranged OTUs; thus, large ranges do not appear to simply result from passive tracking of widespread climatic zones. OTUs with larger ranges and broader climatic niches showed relatively weaker IBD, suggesting that large-ranged species might possess intrinsic attributes that facilitate genetic cohesion across large distances and varied climates. By influencing population divergence and persistence, traits that affect species cohesion may play a central role in large-scale patterns of diversification and species richness.


Asunto(s)
Lagartos , Animales , Australia , Ecosistema , Flujo Génico , Humanos , Lagartos/genética , Filogenia
8.
Mol Phylogenet Evol ; 173: 107516, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35577290

RESUMEN

Genomic data are a powerful tool for the elucidation of evolutionary patterns at the population level and above. The combined analysis of genomic and morphological data can result in species delimitation hypotheses that reflect evolutionary history better than traditional taxonomy or any individual source of evidence. Here, we used thousands of single nucleotide polymorphisms, mitochondrial sequences, and comprehensive morphological data to characterize the evolutionary history of the ridge-tailed monitors in the Varanus acanthurus complex (V. acanthurus, V. baritji, and V. storri), a group of saxicolous lizards with a wide distribution in Australia, the driest vegetated continent. We found substantial genetic structure in the group and identify nine geographically clustered populations. Based on admixture patterns and species delimitation analyses we propose a taxonomic scheme that differs from current taxonomy. We consider V. acanthurus as monotypic, synonymize V. baritji with V. a. insulanicus (as a redefined V. insulanicus), elevate the subspecies of V. storri to full species (V. storri and V. ocreatus), and describe a new species from a previously identified center of endemism. The relationships among the species remain unresolved, likely as a result of fast speciation. Our study highlights the capability of large datasets to illuminate admixture patterns, biogeographic history, and species limits, even when phylogeny is not completely resolved. Furthermore, our results highlight the impact that the Cenozoic aridification of Australia had on saxicolous taxa and the role of mesic rocky escarpments as refugia. These habitats apparently allowed the persistence of lineages that became sources of colonization for arid environments.


Asunto(s)
Lagartos , Animales , Evolución Biológica , Ecosistema , Genoma , Filogenia
9.
Syst Biol ; 70(1): 120-132, 2021 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-32521014

RESUMEN

Organismal interactions drive the accumulation of diversity by influencing species ranges, morphology, and behavior. Interactions vary from agonistic to cooperative and should result in predictable patterns in trait and range evolution. However, despite a conceptual understanding of these processes, they have been difficult to model, particularly on macroevolutionary timescales and across broad geographic spaces. Here, we investigate the influence of biotic interactions on trait evolution and community assembly in monitor lizards (Varanus). Monitors are an iconic radiation with a cosmopolitan distribution and the greatest size disparity of any living terrestrial vertebrate genus. Between the colossal Komodo dragon Varanus komodoensis and the smallest Australian dwarf goannas, Varanus length and mass vary by multiple orders of magnitude. To test the hypothesis that size variation in this genus was driven by character displacement, we extended existing phylogenetic comparative methods which consider lineage interactions to account for dynamic biogeographic history and apply these methods to Australian monitors and marsupial predators. Incorporating both exon-capture molecular and morphological data sets we use a combined evidence approach to estimate the relationships among living and extinct varaniform lizards. Our results suggest that communities of Australian Varanus show high functional diversity as a result of continent-wide interspecific competition among monitors but not with faunivorous marsupials. We demonstrate that patterns of trait evolution resulting from character displacement on continental scales are recoverable from comparative data and highlight that these macroevolutionary patterns may develop in parallel across widely distributed sympatric groups.[Character displacement; comparative methods; phylogenetics; trait evolution; Varanus.].


Asunto(s)
Lagartos , Animales , Australia , Tamaño Corporal , Lagartos/genética , Fenotipo , Filogenia
10.
Syst Biol ; 70(1): 49-66, 2021 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-32359157

RESUMEN

Molecular phylogenies have yielded strong support for many parts of the amphibian Tree of Life, but poor support for the resolution of deeper nodes, including relationships among families and orders. To clarify these relationships, we provide a phylogenomic perspective on amphibian relationships by developing a taxon-specific Anchored Hybrid Enrichment protocol targeting hundreds of conserved exons which are effective across the class. After obtaining data from 220 loci for 286 species (representing 94% of the families and 44% of the genera), we estimate a phylogeny for extant amphibians and identify gene tree-species tree conflict across the deepest branches of the amphibian phylogeny. We perform locus-by-locus genealogical interrogation of alternative topological hypotheses for amphibian monophyly, focusing on interordinal relationships. We find that phylogenetic signal deep in the amphibian phylogeny varies greatly across loci in a manner that is consistent with incomplete lineage sorting in the ancestral lineage of extant amphibians. Our results overwhelmingly support amphibian monophyly and a sister relationship between frogs and salamanders, consistent with the Batrachia hypothesis. Species tree analyses converge on a small set of topological hypotheses for the relationships among extant amphibian families. These results clarify several contentious portions of the amphibian Tree of Life, which in conjunction with a set of vetted fossil calibrations, support a surprisingly younger timescale for crown and ordinal amphibian diversification than previously reported. More broadly, our study provides insight into the sources, magnitudes, and heterogeneity of support across loci in phylogenomic data sets.[AIC; Amphibia; Batrachia; Phylogeny; gene tree-species tree discordance; genomics; information theory.].


Asunto(s)
Fósiles , Genómica , Animales , Anuros , Humanos , Filogenia
11.
Mol Phylogenet Evol ; 161: 107181, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-33892100

RESUMEN

Advances from empirical studies in phylogeography, systematics and species delimitation highlight the importance of integrative approaches for quantifying taxonomic diversity. Genomic data have greatly improved our ability to discern both systematic diversity and evolutionary history. Here we combine analyses of mitochondrial DNA sequences, thousands of genome-wide SNPs and linear and geometric morphometrics on Antaresia, a clade of four currently recognised dwarf pythons from Australia and New Guinea (Antaresia childreni, A. stimsoni, A. maculosa and A. perthensis). Our integrative analyses of phylogenetics, population structure, species delimitation, historical demography and morphometrics revealed that the true evolutionary diversity is not well reflected in the current appraisal of the diversity of the group. We find that Antaresia childreni and A. stimsoni comprise a widespread network of populations connected by gene flow and without evidence of species-level divergence among them. However, A. maculosa shows considerable genetic structuring which leads us to recognise two subspecies in northeastern Australia and a new species in Torres Strait and New Guinea. These two contrasting cases of over and under estimation of diversity, respectively, illustrate the power of thorough integrative approaches into understanding evolution of biodiversity. Furthermore, our analyses of historical demographic patterns highlight the importance of the Kimberley, Pilbara and Cape York as origins of biodiversity in Australia.


Asunto(s)
Boidae/clasificación , Boidae/genética , Filogenia , Filogeografía , Animales , Tamaño Corporal , Boidae/anatomía & histología , ADN Mitocondrial/genética , Flujo Génico/genética
12.
Mol Phylogenet Evol ; 133: 107-119, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30553880

RESUMEN

Palaeoclimatic events and biogeographical processes since the mid-Tertiary have played an important role in shaping the evolution and distribution of Australian fauna. However, their impacts on fauna in southern and arid zone regions of Australia are not well understood. Here we investigate the phylogeography of an Australian scincid lizard, Tiliqua rugosa, across southern Australia using mitochondrial DNA (mtDNA) and 11 nuclear DNA markers (nuDNA), including nine anonymous nuclear loci. Phylogenetic analyses revealed three major mtDNA lineages within T. rugosa, geographically localised north and south of the Murray River in southern Australia, and west of the Nullarbor Plain. Molecular variance and population analyses of both mtDNA and nuDNA haplotypes revealed significant variation among the three populations, although potential introgression of nuDNA markers was also detected for the Northern and Southern population. Coalescent times for major mtDNA lineages coincide with an aridification phase, which commenced after the early Pliocene and increased in intensity during the Late Pliocene-Pleistocene. Species distribution modelling and a phylogeographic diffusion model suggest that the range of T. rugosa may have contracted during the Last Glacial Maximum and the locations of optimal habitat appear to coincide with the geographic origin of several distinct mtDNA lineages. Overall, our analyses suggest that Plio-Pleistocene climatic changes and biogeographic barriers associated with the Nullarbor Plain and Murray River have played a key role in shaping the present-day distribution of genetic diversity in T. rugosa and many additional ground-dwelling animals distributed across southern Australia.


Asunto(s)
Lagartos/clasificación , Animales , Australia , ADN Mitocondrial/química , Clima Desértico , Ecosistema , Haplotipos , Lagartos/genética , Filogenia , Filogeografía , Análisis de Secuencia de ADN , Australia del Sur
13.
Mol Phylogenet Evol ; 141: 106605, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31479732

RESUMEN

The origin of the mammalian order Eulipotyphla has been debated intensively with arguments around whether they began diversifying before or after the Cretaceous-Palaeogene (K-Pg) boundary at 66 Ma. Here, we used an in-solution nucleotide capture method and next generation DNA sequencing to determine the sequence of hundreds of ultra-conserved elements (UCEs), and conducted phylogenomic and molecular dating analyses for the four extant eulipotyphlan lineages-Erinaceidae, Solenodontidae, Soricidae, and Talpidae. Concatenated maximum-likelihood analyses with single or partitioned models and a coalescent species-tree analysis showed that divergences among the four major eulipotyphlan lineages occurred within a short period of evolutionary time, but did not resolve the interrelationships among them. Alternative suboptimal phylogenetic hypotheses received consistently the same amount of support from different UCE loci, and were not significantly different from the maximum likelihood tree topology, suggesting the prevalence of stochastic lineage sorting. Molecular dating analyses that incorporated among-lineage evolutionary rate differences supported a scenario where the four eulipotyphlan families diversified between 57.8 and 63.2 Ma. Given short branch lengths with low support values, traces of rampant genome-wide stochastic lineage sorting, and post K-Pg diversification, we concluded that the crown eulipotyphlan lineages arose through a rapid diversification after the K-Pg boundary when novel niches were created by the mass extinction of species.


Asunto(s)
Secuencia Conservada , Mamíferos/clasificación , Mamíferos/genética , Filogenia , Animales , Composición de Base/genética , Calibración , Secuencia Conservada/genética , Variación Genética , Funciones de Verosimilitud , Factores de Tiempo
14.
Mol Phylogenet Evol ; 136: 119-127, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-30981810

RESUMEN

With just a handful of documented cases of hybridisation in cartilaginous fishes, shark hybridisation remains poorly investigated. Small amounts of admixture have been detected between Galapagos (Carcharhinus galapagensis) and dusky (Carcharhinus obscurus) sharks previously, generating a hypothesis of ongoing hybridisation. We sampled a large number of individuals from areas where the species co-occur (contact zones) across the Pacific Ocean and used both mitochondrial and nuclear-encoded SNPs to examine genetic admixture and introgression between the two species. Using empirical analytical approaches and simulations, we first developed a set of 1873 highly informative SNPs for these two species to evaluate the degree of admixture between them. Overall, results indicate a high discriminatory power of nuclear SNPs (FST = 0.47, p < 0.05) between the two species, unlike mitochondrial DNA (ΦST = 0.00 p > 0.05), which failed to differentiate these species. We identified four hybrid individuals (∼1%) and detected bi-directional introgression between C. galapagensis and C. obscurus in the Gulf of California along the east Pacific coast of the Americas. We emphasize the importance of including a combination of mtDNA and diagnostic nuclear markers to properly assess species identification, detect patterns of hybridisation, and better inform management and conservation of these sharks, especially given the morphological similarities within the genus Carcharhinus.


Asunto(s)
Hibridación Genética , Tiburones/genética , Animales , Teorema de Bayes , California , Simulación por Computador , ADN Mitocondrial/genética , Geografía , Mitocondrias/genética , Océano Pacífico , Filogenia , Polimorfismo de Nucleótido Simple/genética , Tamaño de la Muestra
15.
Am Nat ; 192(4): 432-447, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-30205030

RESUMEN

Population divergence is the first step in allopatric speciation, as has long been recognized in both theoretical models of speciation and empirical explorations of natural systems. All else being equal, lineages with substantial population differentiation should form new species more quickly than lineages that maintain range-wide genetic cohesion through high levels of gene flow. However, there have been few direct tests of the extent to which population differentiation predicts speciation rates as measured on phylogenetic trees. Here, we explicitly test the links between organismal traits, population-level processes, and phylogenetic speciation rates across a diverse clade of Australian lizards that shows remarkable variation in speciation rate. Using genome-wide double digest restriction site-associated DNA data from 892 individuals, we generated a comparative data set on isolation by distance and population differentiation across 104 putative species-level lineages (operational taxonomic units). We find that species show substantial variation in the extent of population differentiation, and this variation is predicted by organismal traits that are thought to be proxies for dispersal and deme size. However, variation in population structure does not predict variation in speciation rate. Our results suggest that population differentiation is not the rate-limiting step in species formation and that other ecological and historical factors are primary determinants of speciation rates at macroevolutionary scales.


Asunto(s)
Especiación Genética , Lagartos/clasificación , Lagartos/genética , Filogenia , Animales , Australia , Flujo Génico , Estudio de Asociación del Genoma Completo , Geografía , Análisis de Secuencia de ADN
16.
Proc Biol Sci ; 284(1854)2017 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-28469025

RESUMEN

Genetic diversity is a fundamental characteristic of species and is affected by many factors, including mutation rate, population size, life history and demography. To better understand the processes that influence levels of genetic diversity across taxa, we collected genome-wide restriction-associated DNA data from more than 500 individuals spanning 76 nominal species of Australian scincid lizards in the genus Ctenotus To avoid potential biases associated with variation in taxonomic practice across the group, we used coalescent-based species delimitation to delineate 83 species-level lineages within the genus for downstream analyses. We then used these genetic data to infer levels of within-population genetic diversity. Using a phylogenetically informed approach, we tested whether variation in genetic diversity could be explained by population size, environmental heterogeneity or historical demography. We find that the strongest predictor of genetic diversity is a novel proxy for census population size: the number of vouchered occurrences in museum databases. However, museum occurrences only explain a limited proportion of the variance in genetic diversity, suggesting that genetic diversity might be difficult to predict at shallower phylogenetic scales.


Asunto(s)
Variación Genética , Genética de Población , Lagartos/genética , Filogenia , Animales , Australia , Lagartos/clasificación , Museos , Densidad de Población , Análisis de Secuencia de ADN
17.
Mol Biol Evol ; 31(9): 2322-30, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24881050

RESUMEN

Marsupials exhibit great diversity in ecology and morphology. However, compared with their sister group, the placental mammals, our understanding of many aspects of marsupial evolution remains limited. We use 101 mitochondrial genomes and data from 26 nuclear loci to reconstruct a dated phylogeny including 97% of extant genera and 58% of modern marsupial species. This tree allows us to analyze the evolution of habitat preference and geographic distributions of marsupial species through time. We found a pattern of mesic-adapted lineages evolving to use more arid and open habitats, which is broadly consistent with regional climate and environmental change. However, contrary to the general trend, several lineages subsequently appear to have reverted from drier to more mesic habitats. Biogeographic reconstructions suggest that current views on the connectivity between Australia and New Guinea/Wallacea during the Miocene and Pliocene need to be revised. The antiquity of several endemic New Guinean clades strongly suggests a substantially older period of connection stretching back to the Middle Miocene and implies that New Guinea was colonized by multiple clades almost immediately after its principal formation.


Asunto(s)
Evolución Biológica , Biología Computacional/métodos , Ecosistema , Marsupiales/genética , Adaptación Biológica , Animales , ADN Mitocondrial/análisis , Evolución Molecular , Marsupiales/clasificación , Filogenia , Filogeografía , Análisis de Secuencia de ADN
18.
Syst Biol ; 63(4): 610-27, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24682412

RESUMEN

The correlation between species diversification and morphological evolution has long been of interest in evolutionary biology. We investigated the relationship between these processes during the radiation of 250+scincid lizards that constitute Australia's most species-rich clade of terrestrial vertebrates. We generated a time-calibrated phylogenetic tree for the group that was more than 85% complete at the species level and collected multivariate morphometric data for 183 species. We reconstructed the dynamics of species diversification and trait evolution using a Bayesian statistical framework (BAMM) that simultaneously accounts for variation in evolutionary rates through time and among lineages. We extended the BAMM model to accommodate time-dependent phenotypic evolution, and we describe several new methods for summarizing and visualizing macroevolutionary rate heterogeneity on phylogenetic trees. Two major clades (Lerista, Ctenotus; >90 spp. each) are associated with high rates of species diversification relative to the background rate across Australian sphenomorphine skinks. The Lerista clade is characterized by relatively high lability of body form and has undergone repeated instances of limb reduction, but Ctenotus is characterized by an extreme deceleration in the rate of body shape evolution. We estimate that rates of phenotypic evolution decreased by more than an order of magnitude in the common ancestor of the Ctenotus clade. These results provide evidence for a modal shift in phenotypic evolutionary dynamics and demonstrate that major axes of morphological variation can be decoupled from species diversification. More generally, the Bayesian framework described here can be used to identify and characterize complex mixtures of dynamic processes on phylogenetic trees. [Bayesian; diversification; evolvability; lizard; macroevolution, punctuated equilibrium, speciation.].


Asunto(s)
Simulación por Computador , Especiación Genética , Lagartos/clasificación , Filogenia , Animales , Biodiversidad , Lagartos/anatomía & histología , Lagartos/genética , Modelos Teóricos
19.
Parasitology ; 142(8): 1066-79, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25877339

RESUMEN

Dicyemids, poorly known parasites of benthic cephalopods, are one of the few phyla in which mitochondrial (mt) genome architecture departs from the typical ~16 kb circular metazoan genome. In addition to a putative circular genome, a series of mt minicircles that each comprises the mt encoded units (I-III) of the cytochrome c oxidase complex have been reported. Whether the structure of the mt minicircles is a consistent feature among dicyemid species is unknown. Here we analyse the complete cytochrome c oxidase subunit I (COI) minicircle molecule, containing the COI gene and an associated non-coding region (NCR), for ten dicyemid species, allowing for first time comparisons between species of minicircle architecture, NCR function and inferences of minicircle replication. Divergence in COI nucleotide sequences between dicyemid species was high (average net divergence = 31.6%) while within species diversity was lower (average net divergence = 0.2%). The NCR and putative 5' section of the COI gene were highly divergent between dicyemid species (average net nucleotide divergence of putative 5' COI section = 61.1%). No tRNA genes were found in the NCR, although palindrome sequences with the potential to form stem-loop structures were identified in some species, which may play a role in transcription or other biological processes.


Asunto(s)
Cefalópodos/parasitología , Variación Genética , Genoma Mitocondrial/genética , Invertebrados/clasificación , Animales , Secuencia de Bases , ADN Mitocondrial/genética , Complejo IV de Transporte de Electrones/genética , Invertebrados/enzimología , Invertebrados/genética , Mitocondrias/enzimología , Mitocondrias/genética , Datos de Secuencia Molecular , Filogenia , ARN no Traducido/genética , Alineación de Secuencia/veterinaria , Análisis de Secuencia de ADN/veterinaria , Especificidad de la Especie
20.
Zootaxa ; 3981(3): 367-84, 2015 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-26250000

RESUMEN

The Magpie Fiddler ray, Trygonorrhina melaleuca Scott 1954, is presently South Australia's (SA) rarest fish, represented by only three museum specimens collected near Adelaide over the past 60 years and listed as Endangered in the IUCN Red List of Threatened Species. However, there is some doubt as to whether the Magpie Fiddler Ray is a different species from the widespread and common Southern Fiddler Ray, Trygonorrhina dumerilii (Castelnau 1873), resulting in two very contrasting scenarios for marine conservation. If the Magpie Fiddler Ray is a black and white patterned variant of the Southern Fiddler Ray then it will be removed from the Red List and appear as a synonym of T. dumerilii. Conversely, if it proves to be a different species then it remains SA's rarest fish species and highly data deficient. We analysed mtDNA and the largest ever nuclear gene dataset (>4,000 loci) applied to chondrichthyan species level systematics from the most recently collected Magpie Fiddler Ray specimens and a geographically representative selection of Southern Fiddler Rays to determine the species status of this enigmatic ray. We found that the Magpie Fiddler Rays share a mitochondrial haplotype with 23 Southern Fiddler Rays and are not differentiated from 35 Southern Fiddler Rays at more than 4000 SNPs derived from DArTseq data. The morphological trait values that are putatively diagnostic for the Magpie Fiddler Ray fall within the range of variation observed among Southern Fiddler Rays. Our analyses are consistent with the notion that the Magpie Fiddler Ray is a rare colour and pattern variant of the widespread and abundant Southern Fiddler Ray. We also identified two hybrids between the Eastern and Southern Fiddler Rays, only the third time that hybrids have been identified in nature in chondrichthyans. Our results provide critical guidance in the assessment of its conservation status and an ending to a 60 year old conundrum for marine conservation.


Asunto(s)
Escarabajos/clasificación , Rajidae/clasificación , Distribución Animal , Estructuras Animales/anatomía & histología , Estructuras Animales/crecimiento & desarrollo , Animales , Australia , Tamaño Corporal , Escarabajos/anatomía & histología , Escarabajos/crecimiento & desarrollo , Color , Ecosistema , Femenino , Masculino , Tamaño de los Órganos , Filogenia , Rajidae/anatomía & histología , Rajidae/genética , Rajidae/crecimiento & desarrollo
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