The Neotropical Phyllomedusa burmeisteri treefrog group includes four diploid (P. bahiana, P. burmeisteri, P. distincta and P. iheringii) and one tetraploid (P. tetraploidea) forms. Here we use mitochondrial and nuclear sequence variation from across its range to verify if recognized morphospecies correspond to phylogenetic clades, examine the origin of the polyploid P. tetraploidea, and compare range wide patterns of diversification to those of other BAF organisms. We compared single gene trees with one Bayesian multi-gene tree, and one Bayesian species tree inferred under a coalescent framework. Our mtDNA phylogenetic analyses showed that P. bahiana, P. burmeisteri and P. iheringii correspond to monophyletic clades, while P. distincta and P. tetraploidea were paraphyletic. The nuclear gene trees were concordant in revealing two moderately supported groups including (i) P. bahiana and P. burmeisteri (northern species) and (ii) P. distincta, P.tetraploidea and P. iheringii (southern species). The multi-gene tree and the species tree retrieved similar topologies, giving high support to the northern and southern clades, and to the sister-taxa relationship between P. tetraploidea and P. distincta. Estimates of (t)MRCA suggest a major split within the P. burmeisteri group at ≈ 5 Myr (between northern and southern groups), while the main clades were originated between ≈ 0.4 and 2.5 Myr, spanning the late Pliocene and Pleistocene. Patterns of geographic and temporal diversification within the group were congruent with those uncovered for other co-distributed organisms. Independent paleoecological and geological data suggest that vicariance associated with climatic oscillations and neotectonic activity may have driven lineage divergence within the P. burmeisteri group. P. tetraploidea probably originated from polyploidization of P. distincta or from a common ancestor.
Parthenogenesis is asexual reproduction without any required participation from males and, as such, is a null model for sexual reproduction. In a comparative context, we can expand our understanding of the evolution and ecology of sex by investigating the consequences of parthenogenesis. In this review, we examine the theoretical predictions of and empirical results on the evolution of asexual reproduction in vertebrates, focusing on recent studies addressing the origins and geographic spread of parthenogenetic lineages and the genomic consequences of an asexual life history. With advances in computational methods and genome technologies, researchers are poised to make rapid and significant progress in studying the origin and evolution of parthenogenesis in vertebrates, thus providing an important perspective on understanding biodiversity patterns of both asexual and sexual populations. Expected final online publication date for the Annual Review of Ecology, Evolution, and Systematics, Volume 51 is November 2, 2020. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
We report new primers for the amplification and sequencing of 11 nuclear markers in squamate reptiles and anuran amphibians (five in squamates, six in anurans). Ten out of the 11 loci are introns (three of which are linked) that were amplified using an exon-primed, introncrossing (EPIC) PCR strategy, whereas an eleventh locus spans part of a protein-coding gene. Squamate and anuran primers were initially developed for Lacerta schreiberi (Squamata: Lacertidae) and Pelodytes spp. (Anura: Pelodytidae), respectively. Cross-species amplification of the squamate markers was evaluated in four genera representing two additional families, whereas for anurans three genera corresponding to three additional families were tested. Three out of the five loci were successfully sequenced in all squamate taxa tested. Cross-amplification of the six anuran markers had lower, but still significant, success. We predict these markers will be of great utility for both population genetics and phylogenetic studies.
Morphological similarity associated to restricted distributions and low dispersal abilities make the direct developing “Terrarana” frogs of the genus Euparkerella a good model for examining diversification processes. We here infer phylogenetic relationships within the genus Euparkerella, using DNA sequence data from one mitochondrial and four nuclear genes coupled with traditional Bayesian phylogenetic reconstruction approaches and more recent coalescent methods of species tree inference. We also used Bayesian clustering analysis and a recent Bayesian coalescent-based approach specifically to infer species delimitation. The analysis of 39 individuals from the four known Euparkerella species uncovered high levels of genetic diversity, especially within the two previously morphologically-defined E. cochranae and E. brasiliensis. Within these species, the gene trees at five independent loci and trees from combined data (concatenated dataset and the species tree) uncovered six deeply diverged and geographically coherent evolutionary units, which may have diverged between the Miocene and the Pleistocene. These six units were also uncovered in the Bayesian clustering analysis, and supported by the Bayesian coalescent-based species delimitation (BPP), and Genealogical Sorting Index (GSI), providing thus strong evidence for underestimation of the current levels of diversity within Euparkerella. The cryptic diversity now uncovered opens new opportunities to examine the origins and maintenance of microendemism in the context of spatial heterogeneity and/or human induced fragmentation of the highly threatened Brazilian Atlantic forest hotspot.
Species limits, phylogeographic and hybridization patterns in Neotropical leaf frogs (Phyllomedusinae). -Zoologica Scripta, 43, 586-604. The taxonomy of many species is still based solely on phenotypic traits, which is often a pitfall for the understanding of evolutionary processes and historical biogeographic patterns, especially between closely related species due to either phenotypic conservatism or plasticity. Two widely distributed Neotropical leaf frogs from the Phyllomedusa burmeisteri species group (P. burmeisteri and Phyllomedusa bahiana) constitute a paramount example of closely related species with relatively unstable taxonomic history due to a large phenotypic variation. Herein, we analysed~260 individuals from 57 localities distributed across the range of the two species to contrast individual phenotypic with an integrative phylogenetic and phylogeographic multilocus approach. We aim to clarify species limits, investigate potential undocumented diversity and examine to what extent taxonomic uncertainties could lead to misleading hypotheses on phylogeographic and interspecific hybridization patterns. Our molecular analysis supports the recognition of the two currently defined species, providing evidences for one novel and highly divergent evolutionary unit within the range of P. burmeisteri, which encompasses its type locality (Rio de Janeiro city). Spatial patterns of genetic and the colour of the hidden areas of the thigh was not congruent, varying considerably both within and between populations of both species. Genetic data showed signs of admixture between both species but do not corroborate the previously inferred wide area of introgression based on the distribution of the intermediate phenotype. Our results suggest that phenotypic variation can result from local adaptations, geographic isolation and/or evolutionary processes and, thus, cannot be used to reliably diagnose P. burmeisteri and P. bahiana. Globally, this study underscores the need of a geographical broad sampling of widespread species and the combination of molecular and phenotypic data to delineate species limits and phylogeographic patterns in species with complex taxonomy. Corresponding author: Tuliana O. Brunes,
-The objective of this study was to evaluate the genetic variability of rice (Oryza sativa) landraces collected in Brazilian small farms. Twelve simple sequence repeat (SSR) markers characterized 417 landraces collected in 1986, 1987 and 2003, in the state of Goiás, Brazil. The number of landraces with long and thin grain type increased in the evaluated period, probably due to market demand. Based on the molecular data, the genetic variability increased during this period and, as per to the factorial correspondence analysis, most of the accessions were grouped according to the year of collection. The incorporation of modern rice cultivars in landrace cultivation areas and the selection carried out by small farmers are the most probable factors responsible for increasing landrace genetic variability, during the evaluated period. Genotype exchange between farmers, selection practice and local environmental adaptation are able to generate novel adapted allele combinations, which can be used by breeding programs, to reinitiate the process.Index terms: Oryza sativa, genotyping, microsatellites, participatory breeding, rice breeding. Variabilidade genética de variedades locais de arroz determinada por marcadores SSR
The evolutionary history of Neotropical organisms has been often interpreted through broad-scale generalizations. The most accepted model of diversification for the Brazilian Atlantic forest (BAF) rely on putative historical stability of northern areas and massive past habitat replacement of its southern range. Here, we use the leaf frog Phyllomedusa distincta, endemic to the southern BAF, to better understand diversification patterns within this underexplored rainforest region. We used an integrative approach coupling fine-scale sampling and multilocus sequence data, with traditional and statistical phylogeographic (multilocus approximate Bayesian computation) methods to explore alternative hypotheses of diversification. We also employed species paleodistribution modeling to independently verify habitat stability upon a spatially explicit model. Our data support two divergent lineages with coherent geographic distribution that span throughout northern and southern ranges. Demographic estimates suggested the Southern lineage has experienced a recent population expansion, whereas the Northern lineage remained more stable. Hypothesis testing supports a scenario of ancient vicariance with recent population expansion. The paleodistribution model revealed habitat discontinuity during the Last Glacial Maximum (LGM) with one area of putative stability within the range of the Northern lineage. Evidence on genetic structure, demography, and paleodistribution of P. distincta support a historically heterogeneous landscape for the southern BAF, with both areas of forest stability and regions where forest occupation is probably recent. We also associate the southern end of the Cubatão shear zone with a phylogeographic break in the BAF. Taken together, our results argue for the idea of multiple mechanisms generating diversity in this biome and underscore the need of fine-scale data in revealing more detailed pictures.
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