Mitochondrion genomes of seven species of the endangered genus Sporophila (Passeriformes: Thraupidae).

We announce the mitochondrial genomes of seven species of the genus Sporophila (S. bouvreuil, S. iberaensis, S. melanogaster, S. minuta, S. nigrorufa, S. pileata, and S. ruficollis) which were validated by comparative genomic and phylogenetic analysis with related species. The mitochondrial genomes of seven passerines of the genus Sporophila were assembled (three complete and four nearly complete genomes) and were validated by reconstructing phylogenetic relations within Thraupidae. The complete mitogenomes ranged from 16,781 bp in S. ruficollis to 16,791 bp in S. minuta. We identified a conserved genome composition within all mitogenomes with 13 protein-coding genes, 22 tRNAs and two rRNAs. We observed a bias in the nucleotide composition and six mutational hotspots in Sporophila mitogenomes. Our mitogenome-based phylogenetic tree has S. minuta, S. maximiliani and S. nigricollis as sister species of the remaining species in the genus. We present new mitogenome sequences for seven Sporophila species, providing new genomic resources that may be useful for research on the evolution, comparative genetics, and conservation of this threatened group.

Development and characterization of microsatellite markers in Stryphnodendron adstringens (Leguminosae).

In this study, we report the development and characterization of 15 new microsatellite markers for Stryphnodendron adstringens (Leguminosae) in order to support future analyses of genetic diversity in populations of this species. In screening with 48 individuals from three different populations of S. adstringens, we tested the amplification of 20 microsatellite loci, of which five are not useful for population genetic studies due to the lack of polymorphisms or amplification failures. For the final set of 15 loci, the number of alleles ranged from 2 to 15, with a total of 116 alleles. The expected heterozygosity ranged from 0.1219 to 0.8965, with an average of 0.6694 per locus. The combined probability of genetic identity (PI = 8.12 × 10-15) and paternity exclusion (Q = 0.99999) estimations showed that the loci may be useful to discriminate between individuals of S. adstringens. Initial cross-amplification tests were satisfactory in three species of the genus Stryphnodendron: S. rotundifolium, S. coriaceum and S. polyphyllum. This new set of markers will be a useful tool for population genetic studies, contributing to the knowledge about the evolutionary history of S. adstringens and, additionally, correlated species.

Complete chloroplast genome sequence of Caryocar brasiliense Camb. (Caryocaraceae) and comparative analysis brings new insights into the plastome evolution of Malpighiales.

Caryocar brasiliense (Caryocaraceae) is a Neotropical tree species widely distributed in Brazilian Savannas. This species is very popular in central Brazil mainly by the use of its fruits in the local cuisine, and indeed it is one of the candidates, among Brazilian native plants, for fast track incorporation into cropping systems. Here we sequenced the complete chloroplast genome of C. brasiliense and used the data to access its genomic resources using high-throughput sequencing. The chloroplast exhibits a genome length of 165,793 bp and the typical angiosperm quadripartite structure with two copies of an inverted repeat sequence (IRa and IRb) of 34,902 bp each, separating a small single copy (SSC) region of 11,852 bp and a large single copy (LSC) region of 84,137 bp. The annotation analysis identified 136 genes being 87 protein-coding, eight rRNA and 37 tRNA genes. We identified 49 repetitive DNA elements and 85 microsatellites. A bayesian phylogenetic analysis helped to understand previously unresolved relationships in Malpighiales, placing Caryocaraceae as a separated group in the order, with high supported nodes. This study synthetizes valuable information for further studies allowing a better understanding of evolutionary patterns in the group and providing resources for future breeding programs.

Genetic diversity in populations of African mahogany (Khaya grandioliola C. DC.) introduced in Brazil.

Given its high-valued wood, the African mahogany (Khaya grandifoliola) has been envisaged as a renewable source of tropical hardwoods in Brazil. However, there are concerns about the hypothesized low diversity among the few K. grandifoliola germplasm sources introduced in the country. Using eight microsatellite markers, we evaluated the genetic diversity and divergence among 53 superior trees selected from three provenances of K. grandifoliola located in the state of Para. These populations are among the oldest plantations (>15 years) in Brazil and, therefore, the country's main seed sources. The average number of alleles per locus was 5.9, expected heterozygosity was moderate (^=0.56) and lower than the high observed heterozygosity (HO=0.74). Therefore, the intrapopulation fixation index was negative (f=-0.31) indicating the possibility that selection of superior trees might have favored heterozygous plants with heterosis. No genetic structure was observed between provenances. The genetic diversity observed within selected trees, with an effective population size (Ne) of 30.4, is comparable to that of natural populations of African and Brazilian mahoganies. Therefore, our results contradict the idea that the genetic diversity of K. grandifoliola introduced in Brazil is low and show that our germplasm can be exploited for breeding purposes.

The complete chloroplast genome of Stryphnodendron adstringens (Leguminosae - Caesalpinioideae): comparative analysis with related Mimosoid species.

Stryphnodendron adstringens is a medicinal plant belonging to the Leguminosae family, and it is commonly found in the southeastern savannas, endemic to the Cerrado biome. The goal of this study was to assemble and annotate the chloroplast genome of S. adstringens and to compare it with previously known genomes of the mimosoid clade within Leguminosae. The chloroplast genome was reconstructed using de novo and referenced-based assembly of paired-end reads generated by shotgun sequencing of total genomic DNA. The size of the S. adstringens chloroplast genome was 162,169 bp. This genome included a large single-copy (LSC) region of 91,045 bp, a small single-copy (SSC) region of 19,014 bp and a pair of inverted repeats (IRa and IRb) of 26,055 bp each. The S. adstringens chloroplast genome contains a total of 111 functional genes, including 77 protein-coding genes, 30 transfer RNA genes, and 4 ribosomal RNA genes. A total of 137 SSRs and 42 repeat structures were identified in S. adstringens chloroplast genome, with the highest proportion in the LSC region. A comparison of the S. adstringens chloroplast genome with those from other mimosoid species indicated that gene content and synteny are highly conserved in the clade. The phylogenetic reconstruction using 73 conserved coding-protein genes from 19 Leguminosae species was supported to be paraphyletic. Furthermore, the noncoding and coding regions with high nucleotide diversity may supply valuable markers for molecular evolutionary and phylogenetic studies at different taxonomic levels in this group.

Cytogenetics of two hylid frogs from Brazilian Cerrado.

Cytogenetic data can be useful for taxonomic and phylogenetic studies, as well as to provide information about chromosome evolution. Therefore, it may help design conservation priorities for some threatened species, such as anurans. Herein, we describe the karyotypes of Scinax constrictus and Ololygon centralis, native endemic species from the Brazilian Cerrado. Chromosome preparations for both species were stained with Giemsa for morphological analyses and then impregnated by the Ag-NOR method for localization of the nucleolar organizer region (NOR). Both species had 24 chromosomes, as confirmed by meiotic analyses, which showed 12 bivalents. Chromosome morphologies presented the same pattern for Scinax and Ololygon compared to species already karyotyped in both genera. The NOR was interstitially located in the long arm of pair 7 in S. constrictus, whereas in O. centralis it was found near the centromere in the long arm of pair 1, thus diverging from what is commonly found for other Ololygon species. Therefore, we provide the first description of the karyotype of O. centralis and the first report of the localization of the NOR for the karyotype of both species. Our study increases the cytogenetic knowledge in species of the genera Scinax and Ololygon, and provide support for further studies on the taxonomy, ecology, and evolution of hylid anurans.

The Cerrado (Brazil) plant cytogenetics database.

Cerrado is a biodiversity hotspot that has lost ca. 50% of its original vegetation cover and hosts ca. 11,000 species belonging to 1,423 genera of phanerogams. For a fraction of those species some cytogenetic characteristics like chromosome numbers and C-value were available in databases, while other valuable information such as karyotype formula and banding patterns are missing. In order to integrate and share all cytogenetic information published for Cerrado species, including frequency of cytogenetic attributes and scientometrics aspects, Cerrado plant species were searched in bibliographic sources, including the 50 richest genera (with more than 45 taxa) and 273 genera with only one species in Cerrado. Determination of frequencies and the database website (http://cyto.shinyapps.io/cerrado) were developed in R. Studies were pooled by employed technique and decade, showing a rise in non-conventional cytogenetics since 2000. However, C-value estimation, heterochromatin staining and molecular cytogenetics are still not common for any family. For the richest and best sampled families, the following modal 2n counts were observed: Oxalidaceae 2n = 12, Lythraceae 2n = 30, Sapindaceae 2n = 24, Solanaceae 2n = 24, Cyperaceae 2n = 10, Poaceae 2n = 20, Asteraceae 2n = 18 and Fabaceae 2n = 26. Chromosome number information is available for only 16.1% of species, while there are genome size data for only 1.25%, being lower than the global percentages. In general, genome sizes were small, ranging from 2C = ca. 1.5 to ca. 3.5 pg. Intra-specific 2n number variation and higher 2n counts were mainly related to polyploidy, which relates to the prevalence of even haploid numbers above the mode of 2n in most major plant clades. Several orphan genera with almost no cytogenetic studies for Cerrado were identified. This effort represents a complete diagnosis for cytogenetic attributes of plants of Cerrado.

Genetic and chemical diversity of Uncaria tomentosa (Willd. ex. Schult.) DC. in the Brazilian Amazon.

Uncaria tomentosa (Willd. ex Schult.) DC., a plant native to the Amazon region, is used widely in popular medicine and by the pharmaceutical industry because of its anti-inflammatory activity. However, the survival of this species is endangered by deforestation and indiscriminate collection, and a preservation plan is urgently required. The objectives of this study were to determine the genetic and chemical variability between and within eight populations of U. tomentosa from the Brazilian states of Acre, Pará and Amapá, and to investigate possible correlations between genetic and geographical distances, and between geographical distances or altitude and the accumulation of bioactive oxindole alkaloids. Three sequence-related amplified polymorphism (SRAP) markers were employed to fingerprint genomic DNA, and the amounts of mitraphylline and isomitraphylline in leaf samples were established by high-performance liquid chromatography. Although significant divergence existed between the tested populations (FST = 0.246), the largest genetic diversity and the highest percentage of polymorphism (95.68%) was found within the population from Mâncio Lima, Acre. Gene flow was considered rather limited (Nm = 1.57), and no correlations between genetic and geographical distances were detected, suggesting that population structure followed an island model. Accumulations of mitraphylline and isomitraphylline varied in the range 32.94 to 0.57 and 3.75 to 0.36 mg g-1 dry weight, respectively. The concentration of isomitraphylline was positively influenced by altitude, such that the population collected at the site with the highest elevation (Tarauacá, Acre) exhibited the greatest alkaloid content. SRAP markers were very efficient in fingerprinting genomic DNA from U. tomentosa populations and clearly showed that genetic variability within populations was greater than between populations. A conservation and management plan should prioritize the creation of germplasm banks to prevent the loss of existing genetic variability, particularly within alkaloid-rich populations such as those of Tarauacá.

Conservation biogeography of the Cerrado's wild edible plants under climate change: Linking biotic stability with agricultural expansion.

UNLABELLED: REMISE OF THE STUDY: Wild edible plants (WEPs) have an important cultural and economic role in human population worldwide. Human impacts are quickly converting natural habitats in agricultural, cattle ranch, and urbanized lands, putting native species on peril of risk of extinction, including some WEPs. Moreover, global climate changes also can pose another threat to species persistency. Here, we established conservation priorities for the Cerrado, a neotropical region in South America with high levels of plant endemism and vulnerability, aiming to assure long-term persistency of 16 most important WEPs. We evaluated these conservation priorities using a conservation biogeography framework using ecological patterns and process at a biogeographical scale to deal with species conservation features. METHODS: We built ecological niche models for 16 WEPs from Cerrado in the neotropics using climate models for preindustrial, past (Last Glacial Maximum) and future (year 2080) time periods to establish climatically stable areas through time, finding refugias for these WEPs. We used a spatial prioritization algorithm based on the spatial pattern of irreplaceability across the neotropics, aiming to ensure the persistence of at least 25% of range size in climatically stable areas for each WEP, using agricultural models as constraints. KEY RESULTS: The Southeast Cerrado was the most biotically stable and irreplaceable region for the WEPs compared with other areas across the neotropics. CONCLUSIONS: Our findings strongly suggest that the Southeast Cerrado should be considered a conservation priority, with new protected areas to be sustainably managed and restored, to guarantee the supply of cultural and ecosystem services provided from the Cerrado's WEPs.

Correlation between genetic diversity and environmental suitability: taking uncertainty from ecological niche models into account.

The hindcast of shifts in the geographical ranges of species as estimated by ecological niche modelling (ENM) has been coupled with phylogeographical patterns, allowing the inference of past processes that drove population differentiation and genetic variability. However, more recently, some studies have suggested that maps of environmental suitability estimated by ENM may be correlated to species' abundance, raising the possibility of using environmental suitability to infer processes related to population demographic dynamics and genetic variability. In both cases, one of the main problems is that there is a wide variation in ENM development methods and climatic models. In this study, we analyse the relationship between heterozygosity (He) and environmental suitability from multiple ENMs for 25 population estimates for Dipteryx alata, a widely distributed, endemic tree species of the Cerrado region of central Brazil. We propose a new approach for generating a statistical distribution of correlations under randomly generated ENM. The confidence intervals from these distributions indicate how model selection with different properties affects the ability to detect a correlation of interest (e.g. the correlation between He and suitability). Additionally, our approach allows us to explore which particular ensemble of ENMs produces the better result for finding an association between environmental suitability and He. Caution is necessary when choosing a method or a climatic data set for modelling geographical distributions, but the new approach proposed here provides a conservative way to evaluate the ability of ensembles to detect patterns of interest.

Isolation and characterization of microsatellite loci in Byrsonima cydoniifolia (Malpighiaceae) and cross-amplification in B. crassifolia.

PREMISE OF THE STUDY: Microsatellite markers were developed and characterized in Byrsonima cydoniifolia (Malpighiaceae) to allow further investigation of genetic variation in natural populations. Cross-amplification was tested in the related species B. crassifolia. • METHODS AND RESULTS: Seventeen microsatellite markers were isolated by a microsatellite-enriched library protocol. Fourteen polymorphic and three monomorphic loci were identified in B. cydoniifolia. The mean number of alleles in the three populations were 6.5, 6.5, and 8.2, ranging from three to 17 for different loci and populations. Mean observed and expected heterozygosities were 0.706 and 0.727, respectively. The fixation index was close to zero for all but two loci. Nine microsatellite loci were successfully cross-amplified in B. crassifolia. • CONCLUSIONS: This new set of microsatellite markers will be a useful tool for genetic studies of B. cydoniifolia, supporting strategies for maintaining the genetic diversity of this species and possibly that of many related species.

A new eigenfunction spatial analysis describing population genetic structure.

Several methods of spatial analyses have been proposed to infer the relative importance of evolutionary processes on genetic population structure. Here we show how a new eigenfunction spatial analysis can be used to model spatial patterns in genetic data. Considering a sample of n local populations, the method starts by modeling the response variable (allele frequencies or phenotypic variation) against the eigenvectors sequentially extracted from a geographic distance matrix (n × n). The relationship between the coefficient of determination (R(2)) of the models and the cumulative eigenvalues, which we named the spatial signal-representation (SSR) curve, can be more efficient than Moran's I correlograms in describing different patterns. The SSR curve was also applied to simulated data (under distinct scenarios of population differentiation) and to analyze spatial patterns in alleles from microsatellite data for 25 local populations of Dipteryx alata, a tree species endemic to the Brazilian Cerrado. The SSR curves are consistent with previous phylogeographical patterns of the species, revealing combined effects of isolation-by-distance and range expansion. Our analyses demonstrate that the SSR curve is a useful exploratory tool for describing spatial patterns of genetic variability and for selecting spatial eigenvectors for models aiming to explain spatial responses to environmental variables and landscape features.

Geographical patterns of turnover and nestedness-resultant components of allelic diversity among populations.

The analysis of geographical patterns in population divergence has always been a powerful way to infer microevolutionary processes involved in population differentiation, and several approaches have been used to investigate such patterns. Most frequently, multivariate spatial patterns of population differentiation are analyzed by computing pairwise genetic distances or F(ST) (or related statistics, such as ϕ(ST) from AMOVA), which are then correlated with geographical distances or landscape features. However, when calculating distances, especially based on presence-absence of alleles in local populations, there would be a confounding effect of allelic richness differences in the population differentiation. Moreover, the relative magnitude of these components and their spatial patterns can help identifying microevolutionary processes driving population differentiation. Here we show how recent methodological advances in ecological community analyses that allows partitioning dissimilarity into turnover (turnover) and richness differences, or nestedness-resultant dissimilarity, can be applied to allelic variation data, using an endemic Cerrado tree (Dipteryx alata) as a case study. Individuals from 15 local populations were genotyped for eight microsatellite loci, and pairwise dissimilarities were computed based on presence-absence of alleles. The turnover of alleles among populations represented 69 % of variation in dissimilarity, but only the richness difference component shows a clear spatial structure, appearing as a westward decrease of allelic richness. We show that decoupling richness difference and turnover components of allelic variation reveals more clearly how similarity among populations reflects geographical patterns in allelic diversity that can be interpreted in respect to historical range expansion in the species.

Development of microsatellite markers for the neotropical tree species Dipteryx alata (Fabaceae).

PREMISE OF THE STUDY: Microsatellite markers were developed for the population genetic analyses of the neotropical tree Dipteryx alata (Fabaceae). METHODS AND RESULTS: Microsatellites were developed from a genomic shotgun library. Polymorphism at each microsatellite loci was analyzed based on 94 individuals from three populations. Eight loci amplified successfully and presented one to 10 alleles, and expected heterozygosities ranged from 0.097 to 0.862. Four loci also amplified in Pterodon emarginatus and presented similar polymorphism. CONCLUSION: The eight microsatellite primer pairs are potentially suitable for population genetic studies and successfully amplified in another Fabaceae species.

A review of techniques for spatial modeling in geographical, conservation and landscape genetics

Most evolutionary processes occur in a spatial context and several spatial analysis techniques have been employed in an exploratory context. However, the existence of autocorrelation can also perturb significance tests when data is analyzed using standard correlation and regression techniques on modeling genetic data as a function of explanatory variables. In this case, more complex models incorporating the effects of autocorrelation must be used. Here we review those models and compared their relative performances in a simple simulation, in which spatial patterns in allele frequencies were generated by a balance between random variation within populations and spatially-structured gene flow. Notwithstanding the somewhat idiosyncratic behavior of the techniques evaluated, it is clear that spatial autocorrelation affects Type I errors and that standard linear regression does not provide minimum variance estimators. Due to its flexibility, we stress that principal coordinate of neighbor matrices (PCNM) and related eigenvector mapping techniques seem to be the best approaches to spatial regression. In general, we hope that our review of commonly used spatial regression techniques in biology and ecology may aid population geneticists towards providing better explanations for population structures dealing with more complex regression problems throughout geographic space.

Population structure of Eupemphix nattereri (Amphibia, Anura, Leiuperidae) from Central Brazil

This study reports on 156 specimens of the amphibian Eupemphix nattereri, a widely distributed leiuperid, obtained from 11 municipalities of central Brazil. The extent of genetic variation was quantified by determining the mean number of alleles per locus and the proportion of polymorphic loci. An analysis of molecular variance (AMOVA) was performed on the random amplified polymorphic DNA (RAPD) haplotypes. The genetic distances obtained by calculating pairwise phist among local samples were used to determine population relationships using the unweighted pair-group method (UPGMA) and non-metric multidimensional scaling (NMDS). The cophenetic correlation was calculated to confirm agreement between the genetic matrix and the unweighted pair group method with averages (UPGMA) dendrogram. To determine if genetic distances were correlated to geographical distances we constructed pairwise genetic distance and geographical distance matrices and compared them using the Mantel test. The AMOVA results indicated significant genetic differences (p < 0.001) between E. nattereri populations, representing 69.5 percent of the within population genetic diversity. The Mantel test showed no significant correlation (r = 0.03; p = 0.45) between the genetic and geographical distance matrices. Our findings indicate that the genetic variation of E. nattereri populations was randomly distributed in geographic space and that gene flow for this species is probably structured at spatial scales smaller than those between our samples.

RAPD variation and population genetic structure of Physalaemus cuvieri (Anura: Leptodactylidae) in Central Brazil.

Studies about the organization of the genetic variability and population structure in natural populations are used either to understand microevolutionary processes or the effects of isolation by human-inducted landscape modifications. In this paper, we analyzed patterns of genetic population structure using 126 RAPD loci scored for 214 individuals of Physalaemus cuvieri, sampled from 18 local populations. Around 97% of these loci were polymorphic. The among-population variation component (Phi(ST)) obtained by AMOVA was equal to 0.101 and theta B obtained using a Bayesian approach for dominant markers was 0.103. Genetic divergence, analyzed by Mantel spatial correlogram, revealed only a short-distance significant correlation between genetic and geographic distances. This is expected if low levels of population differentiation, due to high abundance buffering the effect of stochastic processes, are combined with low spatially restricted gene flow. Although this may be consistent with the current knowledge of species' biology, the spatial distribution of local populations observed in this study also suggest that, at least in part, recent human occupation and habitat fragmentation may also explain part of the interpopulational component of the genetic variation.

Optimization procedures for establishing reserve networks for biodiversity conservation taking into account population genetic structure

Conservation genetics has been focused on the ecological and evolutionary persistence of targets (species or other intraspecific units), especially when dealing with narrow-ranged species, and no generalized solution regarding the problem of where to concentrate conservation efforts for multiple genetic targets has yet been achieved. Broadly distributed and abundant species allow the identification of evolutionary significant units, management units, phylogeographical units or other spatial patterns in genetic variability, including those generated by effects of habitat fragmentation caused by human activities. However, these genetic units are rarely considered as priority conservation targets in regional conservation planning procedures. In this paper, we discuss a theoretical framework in which target persistence and genetic representation of targets defined using multiple genetic criteria can be explicitly incorporated into the broad-scale reserve network models used to optimize biodiversity conservation based on multiple species data. When genetic variation can be considered discrete in geographical space, the solution is straightforward, and each spatial unit must be considered as a distinct target. But methods for dealing with continuous genetic variation in space are not trivial and optimization procedures must still be developed. We present a simple heuristic and sequential algorithm to deal with this problem by combining multiple networks of local populations of multiple species in which minimum separation distance between conserved populations is a function of spatial autocorrelation patterns of genetic variability within each species.

Multiple Mantel tests and isolation-by-distance, taking into account long-term historical divergence.

Mantel tests of matrix correspondence have been widely used in population genetics to examine microevolutionary processes, such as isolation-by-distance (IBD). We used partial and multiple Mantel tests to simultaneously test long-term historical effects and current divergence and equilibrium processes, such as IBD. We used these procedures to calculate genetic divergence among Eugenia dysenterica (Myrtaceae) populations in Central Brazil. The Nei's genetic distances between pairs of local populations were strongly correlated with geographic distances, suggesting an IBD process, but field observations and the geographic distribution of the samples suggest that populations may have been subjected to more complex evolutionary processes of genetic divergence. Partial Mantel regression was used to partition the effects of geographic structure and long-term divergence associated with a possible historical barrier. The R(2) of the model with both effects was 73.3%, and after the partition 21.9% of the variation in the genetic distances could be attributed to long-term historical divergence alone, whereas only 1.5% of the variation in genetic distances could be attributed to IBD. As expected, there was a large overlap between these processes when explaining genetic divergence, so it was not possible to entirely partition divergence between historical and contemporary processes.

Null expectation of spatial correlograms under a stochastic process of genetic divergence with small sample sizes

Nesse artigo, um processo estocástico Ornstein-Uhlenbeck foi utilizado para simular a relaçäo exponencial entre divergência genética e distância geográfica, conforme é esperado em modelos de isolamento-por-distância, alpondras ou coalescência. As simulaçöes foram realizadas a partir de um dendrograma UPGMA estimado a partir das distâncias geográficas entre 13 populaçöes locais. As superfícies espaciais de freqüências alélicas simuladas foram analisadas através de autocorrelaçäo espacial e construçäo de distâncias genéticas de Nei, com base em diferentes números de alelos. A divergência entre populaçöes locais produziu padröes espaciais significativos, tanto em nível univariado (correlogramas espaciais) quanto em nível multivariado (teste de Mantel entre distâncias de Nei e distâncias geográficas). Entretanto, se as análises säo baseadas em um pequeno número de populaçöes locais, os perfis dos correlogramas variam consideravelmente e as distâncias Manhattan calculadas entre eles podem ser maiores do que as previamente estabelecidas em outros estudos de simulaçäo. O método proposto permite assim estabelecer uma amplitude de perfis que podem ser obtidos pelo mesmo processo estocástico de divergência genética. A comparaçäo de correlogramas observados com esses perfis permite assim evitar o uso de outros mecanismos microevolutivos para explicar essa divergência genética.