Specimen collection is essential for modern science.

Natural history museums are vital repositories of specimens, samples and data that inform about the natural world; this Formal Comment revisits a Perspective that advocated for the adoption of compassionate collection practices, querying whether it will ever be possible to completely do away with whole animal specimen collection.

Contrasting drivers of diversity in hosts and parasites across the tropical Andes.

Geographic turnover in community composition is created and maintained by eco-evolutionary forces that limit the ranges of species. One such force may be antagonistic interactions among hosts and parasites, but its general importance is unknown. Understanding the processes that underpin turnover requires distinguishing the contributions of key abiotic and biotic drivers over a range of spatial and temporal scales. Here, we address these challenges using flexible, nonlinear models to identify the factors that underlie richness (alpha diversity) and turnover (beta diversity) patterns of interacting host and parasite communities in a global biodiversity hot spot. We sampled 18 communities in the Peruvian Andes, encompassing ∼1,350 bird species and ∼400 hemosporidian parasite lineages, and spanning broad ranges of elevation, climate, primary productivity, and species richness. Turnover in both parasite and host communities was most strongly predicted by variation in precipitation, but secondary predictors differed between parasites and hosts, and between contemporary and phylogenetic timescales. Host communities shaped parasite diversity patterns, but there was little evidence for reciprocal effects. The results for parasite communities contradicted the prevailing view that biotic interactions filter communities at local scales while environmental filtering and dispersal barriers shape regional communities. Rather, subtle differences in precipitation had strong, fine-scale effects on parasite turnover while host-community effects only manifested at broad scales. We used these models to map bird and parasite turnover onto the ecological gradients of the Andean landscape, illustrating beta-diversity hot spots and their mechanistic underpinnings.

Predictors of genomic diversity within North American squamates.

Comparisons of intraspecific genetic diversity across species can reveal the roles of geography, ecology, and life history in shaping biodiversity. The wide availability of mitochondrial DNA (mtDNA) sequences in open-access databases makes this marker practical for conducting analyses across several species in a common framework, but patterns may not be representative of overall species diversity. Here, we gather new and existing mtDNA sequences and genome-wide nuclear data (genotyping-by-sequencing; GBS) for 30 North American squamate species sampled in the Southeastern and Southwestern United States. We estimated mtDNA nucleotide diversity for 2 mtDNA genes, COI (22 species alignments; average 16 sequences) and cytb (22 species; average 58 sequences), as well as nuclear heterozygosity and nucleotide diversity from GBS data for 118 individuals (30 species; 4 individuals and 6,820 to 44,309 loci per species). We showed that nuclear genomic diversity estimates were highly consistent across individuals for some species, while other species showed large differences depending on the locality sampled. Range size was positively correlated with both cytb diversity (phylogenetically independent contrasts: R2 = 0.31, P = 0.007) and GBS diversity (R2 = 0.21; P = 0.006), while other predictors differed across the top models for each dataset. Mitochondrial and nuclear diversity estimates were not correlated within species, although sampling differences in the data available made these datasets difficult to compare. Further study of mtDNA and nuclear diversity sampled across species' ranges is needed to evaluate the roles of geography and life history in structuring diversity across a variety of taxonomic groups.

Phylogenetics and the evolution of terrestriality in mudskippers (Gobiidae: Oxudercinae).

The initial vertebrate conquest of land by stegocephalians (Sarcopterygia) allowed access to new resources and exploitation of untapped niches precipitating a major phylogenetic diversification. However, a paucity of fossils has left considerable uncertainties about phylogenetic relationships and the eco-morphological stages in this key transition in Earth history. Among extant actinopterygians, three genera of mudskippers (Gobiidae: Oxudercinae), Boleophthalmus, Periophthalmus and Periophthalmodon are the most terrestrialized, with vertebral, appendicular, locomotory, respiratory, and epithelial specializations enabling overland excursions up to 14 h. Unlike early stegocephalians, the ecologies and morphologies of the 45 species of oxudercines are well known, making them viable analogs for the initial vertebrate conquest of land. Nevertheless, they have received little phylogenetic attention. We compiled the largest molecular dataset to date, with 29 oxudercine species, and 5 nuclear and mitochondrial loci. Phylogenetic and comparative analyses revealed strong support for two independent terrestrial transitions, and a complex suit of ecomorphological forms in estuarine environments. Furthermore, neither Oxudercinae nor their presumed sister-group the eel gobies (Amblyopinae, a group of elongated gobies) were monophyletic with respect to each other, requiring a merging of these two subfamilies and revealing an expansion of phenotypic variation within the "mudskipper" clade. We did not find support for the expected linear model of ecomorphological and locomotory transition from fully aquatic, to mudswimming, to pectoral-aided mudswimming, to lobe-finned terrestrial locomotion proposed by earlier morphological studies. This high degree of convergent or parallel transitions to terrestriality, and apparent divergent directions of estuarine adaptation, promises even greater potential for this clade to illuminate the conquest of land. Future work should focus on these less-studied species with "transitional" and other mud-habitat specializations to fully resolve the dynamics of this diversification.

Inter- and intra-archipelago dynamics of population structure and gene flow in a Polynesian bird.

Islands are separated by natural barriers that prevent gene flow between terrestrial populations and promote allopatric diversification. Birds in the South Pacific are an excellent model to explore the interplay between isolation and gene flow due to the region's numerous archipelagos and well-characterized avian communities. The wattled honeyeater complex (Foulehaio spp.) comprises three allopatric species that are widespread and common across Fiji, Tonga, Samoa, and Wallis and Futuna. Here, we explored patterns of diversification within and among these lineages using genomic and morphometric data. We found support for three clades of Foulehaio corresponding to three recognized species. Within F. carunculatus, population genetic analyses identified nine major lineages, most of which were composed of sub-lineages that aligned nearly perfectly to individual island populations. Despite genetic structure and great geographic distance between populations, we found low levels of gene flow between populations in adjacent archipelagos. Additionally, body size of F. carunculatus varied randomly with respect to evolutionary history (as Ernst Mayr predicted), but correlated negatively with island size, consistent with the island rule. Our findings support a hypothesis that widespread taxa can show population structure between immediately adjacent islands, and likely represent many independent lineages loosely connected by gene flow.

Detecting turnover among complex communities using null models: a case study with sky-island haemosporidian parasites.

Turnover in species composition between sites, or beta diversity, is a critical component of species diversity that is typically influenced by geography, environment, and biotic interactions. Quantifying turnover is particularly challenging, however, in multi-host, multi-parasite assemblages where undersampling is unavoidable, resulting in inflated estimates of turnover and uncertainty about its spatial scale. We developed and implemented a framework using null models to test for community turnover in avian haemosporidian communities of three sky islands in the southwestern United States. We screened 776 birds for haemosporidian parasites from three genera (Parahaemoproteus, Plasmodium, and Leucocytozoon) by amplifying and sequencing a mitochondrial DNA barcode. We detected infections in 280 birds (36.1%), sequenced 357 infections, and found a total of 99 parasite haplotypes. When compared to communities simulated from a regional pool, we observed more unique, single-mountain haplotypes and fewer haplotypes shared among three mountain ranges than expected, indicating that haemosporidian communities differ to some degree among adjacent mountain ranges. These results were robust even after pruning datasets to include only identical sets of host species, and they were consistent for two of the three haemosporidian genera. The two more distant mountain ranges were more similar to each other than the one located centrally, suggesting that the differences we detected were due to stochastic colonization-extirpation dynamics. These results demonstrate that avian haemosporidian communities of temperate-zone forests differ on relatively fine spatial scales between adjacent sky islands. Null models are essential tools for testing the spatial scale of turnover in complex, undersampled, and poorly known systems.

Deeply conserved susceptibility in a multi-host, multi-parasite system.

Variation in susceptibility is ubiquitous in multi-host, multi-parasite assemblages, and can have profound implications for ecology and evolution in these systems. The extent to which susceptibility to parasites is phylogenetically conserved among hosts can be revealed by analysing diverse regional communities. We screened for haemosporidian parasites in 3983 birds representing 40 families and 523 species, spanning ~ 4500 m elevation in the tropical Andes. To quantify the influence of host phylogeny on infection status, we applied Bayesian phylogenetic multilevel models that included a suite of environmental, spatial, temporal, life history and ecological predictors. We found evidence of deeply conserved susceptibility across the avian tree; host phylogeny explained substantial variation in infection status, and results were robust to phylogenetic uncertainty. Our study suggests that susceptibility is governed, in part, by conserved, latent aspects of anti-parasite defence. This demonstrates the importance of deep phylogeny for understanding present-day ecological interactions.

Targeted Sampling and Target Capture: Assessing Phylogeographic Concordance with Genome-wide Data.

Comparative phylogeography provides the necessary framework to examine the factors influencing population divergence, persistence, and change over time. Avise (2000) outlined four aspects of concordance that result when data exhibit significant phylogeographic signal: concordance among sites within a locus, among multiple loci within a species, among multiple species within a region, and between genetic patterns and established biogeographic provinces. To fully address each aspect of concordance, we combined target capture of a set of orthologous loci with targeted geographic sampling of multiple species, thus removing any variability introduced by using different genetic markers and heterogeneous sampling distributions. We used hybrid enrichment and high-throughput sequencing of four anuran species sampled from 36 congruent localities in the Southeastern United States Coastal Plain, a region that represents one of the classic systems in phylogeography. In total, we recovered > 375 of the same nuclear loci across species and assembled mitochondrial genomes, resulting in one of the most comprehensive comparative phylogeographic datasets in any region or taxon to date. We used these data to evaluate concordance, compare genetic structure across species, and test previously described biogeographic features in the region including major river drainages and suture zones. We then applied a recently-developed framework to quantify concordance across species using phylogeographic concordance factors. For the four species examined, which have higher dispersal and potentially limited structure compared to many amphibians, we found poor resolution in individual nuclear gene trees even with long (~ 1400 bp) nuclear sequences. The mitochondrial and multi-locus nuclear datasets, however, produced similar patterns within species, indicated high discordance among species, and suggested little correspondence of genetic patterns with putative biogeographic barriers. Variation in the phylogeographic structure detected may be related to differences in natural history, in that the two habitat generalists exhibited less structure. Our study demonstrates the utility of combining target capture, which is highly repeatable and produces comparable datasets, with a targeted sampling strategy to quantify phylogeographic concordance across diverse taxa in a region with a complex history.

Bell's Palsy in Children (BellPIC): protocol for a multicentre, placebo-controlled randomized trial.

BACKGROUND: Bell's palsy or acute idiopathic lower motor neurone facial paralysis is characterized by sudden onset paralysis or weakness of the muscles to one side of the face controlled by the facial nerve. While there is high level evidence in adults demonstrating an improvement in the rate of complete recovery of facial nerve function when treated with steroids compared with placebo, similar high level studies on the use of steroids in Bell's palsy in children are not available. The aim of this study is to assess the utility of steroids in Bell's palsy in children in a randomised placebo-controlled trial. METHODS/DESIGN: We are conducting a randomised, triple-blinded, placebo controlled trial of the use of prednisolone to improve recovery from Bell's palsy at 1 month. Study sites are 10 hospitals within the Australian and New Zealand PREDICT (Paediatric Research in Emergency Departments International Collaborative) research network. 540 participants will be enrolled. To be eligible patients need to be aged 6 months to < 18 years and present within 72 hours of onset of clinician diagnosed Bell's palsy to one of the participating hospital emergency departments. Patients will be excluded in case of current use of or contraindications to steroids or if there is an alternative diagnosis. Participants will receive either prednisolone 1 mg/kg/day to a maximum of 50 mg/day or taste matched placebo for 10 days. The primary outcome is complete recovery by House-Brackmann scale at 1 month. Secondary outcomes include assessment of recovery using the Sunnybrook scale, the emotional and functional wellbeing of the participants using the Pediatric Quality of Life Inventory and Child Health Utility 9D Scale, pain using Faces Pain Scale Revised or visual analogue scales, synkinesis using a synkinesis assessment questionnaire and health utilisation costs at 1, 3 and 6 months. Participants will be tracked to 12 months if not recovered earlier. Data analysis will be by intention to treat with primary outcome presented as differences in proportions and an odds ratio adjusted for site and age. DISCUSSION: This large multicenter randomised trial will allow the definitive assessment of the efficacy of prednisolone compared with placebo in the treatment of Bell's palsy in children. TRIAL REGISTRATION: The study is registered with the Australian New Zealand Clinical Trials Registry ACTRN12615000563561 (1 June 2015).

Phylogeographic inference using Bayesian model comparison across a fragmented chorus frog species complex.

Fragmented species complexes provide an interesting system for investigating biogeographic history and the present distribution of genetic variation. Recent advances in sequencing technology and statistical phylogeography enable the collection and rigorous analysis of large multilocus data sets, but designing studies that produce meaningful phylogeographic inferences remains challenging. We implemented a Bayesian model comparison approach to investigate previous biogeographic hypotheses while simultaneously inferring the presence of genetic structure in a chorus frog species complex. The Illinois chorus frog (Pseudacris illinoensis), originally described as a subspecies of the broadly distributed Strecker's chorus frog (Pseudacris streckeri), occurs in small, disjunct regions associated with scarce sand prairie habitats that have been impacted by human development. We used high-throughput sequencing to develop and collect a multitiered genetic data set comprised of three different marker types (23 anonymous nuclear sequence loci, four mitochondrial genes and 14 microsatellite loci) designed to address questions across different evolutionary timescales. Phylogenetic analyses uncovered a deep divergence between populations in the Edwards Plateau of central Texas and all other P. streckeri/P. illinoensis populations, but suggest the disjunct distribution of P. illinoensis occurred more recently. Our best-supported migration model is consistent with the hypothesis that central Texas represented a refugium from which populations expanded via multiple routes. This model also indicates that disjunct northern and southern regions of P. illinoensis should be considered genetically distinct management units. Our study provides an evolutionary context for future studies and conservation efforts in P. illinoensis and demonstrates the utility of model-based approaches for phylogeographic inference.

Measles Outbreak Associated with Vaccine Failure in Adults--Federated States of Micronesia, February-August 2014.

On May 15, 2014, CDC was notified of two laboratory-confirmed measles cases in the Federated States of Micronesia (FSM), after 20 years with no reported measles. FSM was assisted by the World Health Organization (WHO), the United Nations Children's Fund (UNICEF), and CDC in investigating suspected cases, identify contacts, conduct analyses to guide outbreak vaccination response, and review vaccine cold chain practices. During February­August, three of FSM's four states reported measles cases: Kosrae (139 cases), Pohnpei (251), and Chuuk (3). Two thirds of cases occurred among adults aged ≥20 years; of these, 49% had received ≥2 doses of measles-containing vaccine (MCV). Apart from infants aged <12 months who were too young for routine vaccination, measles incidence was lower among children than adults. A review of current cold chain practices in Kosrae revealed minor weaknesses; however, an absence of historical cold chain maintenance records precluded an evaluation of earlier problems. Each state implemented vaccination campaigns targeting children as young as age 6 months through adults up to age 57 years. The preponderance of cases in this outbreak associated with vaccine failure in adults highlights the need for both thorough case investigation and epidemiologic analysis to guide outbreak response vaccination. Routine childhood vaccination coverage achieved in recent years limited the transmission of measles among children. Even in areas where transmission has not occurred for years, maintaining high 2-dose MCV coverage through routine and supplemental immunization is needed to prevent outbreaks resulting from increased measles susceptibility in the population.

Species tree estimation of North American chorus frogs (Hylidae: Pseudacris) with parallel tagged amplicon sequencing.

The field of phylogenetics is changing rapidly with the application of high-throughput sequencing to non-model organisms. Cost-effective use of this technology for phylogenetic studies, which often include a relatively small portion of the genome but several taxa, requires strategies for genome partitioning and sequencing multiple individuals in parallel. In this study we estimated a multilocus phylogeny for the North American chorus frog genus Pseudacris using anonymous nuclear loci that were recently developed using a reduced representation library approach. We sequenced 27 nuclear loci and three mitochondrial loci for 44 individuals on 1/3 of an Illumina MiSeq run, obtaining 96.5% of the targeted amplicons at less than 20% of the cost of traditional Sanger sequencing. We found heterogeneity among gene trees, although four major clades (Trilling Frog, Fat Frog, crucifer, and West Coast) were consistently supported, and we resolved the relationships among these clades for the first time with strong support. We also found discordance between the mitochondrial and nuclear datasets that we attribute to mitochondrial introgression and a possible selective sweep. Bayesian concordance analysis in BUCKy and species tree analysis in (*)BEAST produced largely similar topologies, although we identify taxa that require additional investigation in order to clarify taxonomic and geographic range boundaries. Overall, we demonstrate the utility of a reduced representation library approach for marker development and parallel tagged sequencing on an Illumina MiSeq for phylogenetic studies of non-model organisms.

Dynamics of Amphibian Pathogen Detection Using Extended Museum Specimens.

Natural history collections have long served as the foundation for understanding our planet's biodiversity, yet they remain a largely untapped resource for wildlife disease studies. Extended specimens include multiple data types and specimen preparations that capture the phenotype and genotype of an organism and its symbionts-but preserved tissues may not always be optimized for downstream detection of various pathogens. Frogs are infected by an array of pathogens including Batrachochytrium dendrobatidis (Bd), Ranavirus (Rv), and Amphibian Perkinsea (Pr), which provides the opportunity to study differences in detection dynamics across tissue types. We used quantitative PCR protocols to screen two tissue types commonly deposited in museum collections, toe clips and liver, from two closely related host species, Rana catesbeiana and Rana clamitans. We compared Bd, Rv, and Pr infection prevalence and intensity between species and tissue types and found no significant difference in prevalence between species, but Bd intensity was higher in R. clamitans than R. catesbeiana. Toe tissue exhibited significantly higher Bd infection loads and was more useful than liver for detecting Bd infections. In contrast, Rv was detected from more liver than toe tissues, but the difference was not statistically significant. Our results support the use of extended specimen collections in amphibian disease studies and demonstrate that broader tissue sampling at the time of specimen preparation can maximize their utility for downstream multipathogen detection.

Predicting amphibian intraspecific diversity with machine learning: Challenges and prospects for integrating traits, geography, and genetic data.

The growing availability of genetic data sets, in combination with machine learning frameworks, offers great potential to answer long-standing questions in ecology and evolution. One such question has intrigued population geneticists, biogeographers, and conservation biologists: What factors determine intraspecific genetic diversity? This question is challenging to answer because many factors may influence genetic variation, including life history traits, historical influences, and geography, and the relative importance of these factors varies across taxonomic and geographic scales. Furthermore, interpreting the influence of numerous, potentially correlated variables is difficult with traditional statistical approaches. To address these challenges, we analysed repurposed data using machine learning and investigated predictors of genetic diversity, focusing on Nearctic amphibians as a case study. We aggregated species traits, range characteristics, and >42,000 genetic sequences for 299 species using open-access scripts and various databases. After identifying important predictors of nucleotide diversity with random forest regression, we conducted follow-up analyses to examine the roles of phylogenetic history, geography, and demographic processes on intraspecific diversity. Although life history traits were not important predictors for this data set, we found significant phylogenetic signal in genetic diversity within amphibians. We also found that salamander species at northern latitudes contained low genetic diversity. Data repurposing and machine learning provide valuable tools for detecting patterns with relevance for conservation, but concerted efforts are needed to compile meaningful data sets with greater utility for understanding global biodiversity.

Feasibility Study of the World Health Organization Health Care Facility-Based Antimicrobial Stewardship Toolkit for Low- and Middle-Income Countries.

Antimicrobial stewardship (AMS) has emerged as a systematic approach to optimize antimicrobial use and reduce antimicrobial resistance. To support the implementation of AMS programs, the World Health Organization developed a draft toolkit for health care facility AMS programs in low- and middle-income countries. A feasibility study was conducted in Bhutan, the Federated States of Micronesia, Malawi, and Nepal to obtain local input on toolkit content and implementation of AMS programs. This descriptive qualitative study included semi-structured interviews with national- and facility-level stakeholders. Respondents identified AMS as a priority and perceived the draft toolkit as a much-needed document to further AMS program implementation. Facilitators for implementing AMS included strong national and facility leadership and clinical staff engagement. Barriers included lack of human and financial resources, inadequate regulations for prescription antibiotic sales, and insufficient AMS training. Action items for AMS implementation included improved laboratory surveillance, establishment of a stepwise approach for implementation, and mechanisms for reporting and feedback. Recommendations to improve the AMS toolkit's content included additional guidance on defining the responsibilities of the committees and how to prioritize AMS programming based on local context. The AMS toolkit was perceived to be an important asset as countries and health care facilities move forward to implement AMS programs.

Genomic sequence capture of haemosporidian parasites: Methods and prospects for enhanced study of host-parasite evolution.

Avian malaria and related haemosporidians (Plasmodium, [Para]Haemoproteus and Leucocytoozoon) represent an exciting multihost, multiparasite system in ecology and evolution. Global research in this field accelerated after the publication in 2000 of PCR protocols to sequence a haemosporidian mitochondrial (mtDNA) barcode and the development in 2009 of an open-access database to document the geographic and host ranges of parasite mtDNA haplotypes. Isolating haemosporidian nuclear DNA from bird hosts, however, has been technically challenging, slowing the transition to genomic-scale sequencing techniques. We extend a recently developed sequence capture method to obtain hundreds of haemosporidian nuclear loci from wild bird samples, which typically have low levels of infection, or parasitemia. We tested 51 infected birds from Peru and New Mexico and evaluated locus recovery in light of variation in parasitemia, divergence from reference sequences and pooling strategies. Our method was successful for samples with parasitemia as low as ~0.02% (2 of 10,000 blood cells infected) and mtDNA divergence as high as 15.9% (one Leucocytozoonsample), and using the most cost-effective pooling strategy tested. Phylogenetic relationships estimated with >300 nuclear loci were well resolved, providing substantial improvement over the mtDNA barcode. We provide protocols for sample preparation and sequence capture including custom probe sequences and describe our bioinformatics pipeline using atram 2.0, phyluce and custom Perl/Python scripts. This approach can be applied to thousands of avian samples that have already been found to have haemosporidian infections of at least moderate intensity, greatly improving our understanding of parasite speciation, biogeography and evolutionary dynamics.

Ecology, not distance, explains community composition in parasites of sky-island Audubon's Warblers.

Haemosporidian parasites of birds are ubiquitous in terrestrial ecosystems, but their coevolutionary dynamics remain poorly understood. If species turnover in parasites occurs at a finer scale than turnover in hosts, widespread hosts would encounter diverse parasites, potentially diversifying as a result. Previous studies have shown that some wide-ranging hosts encounter varied haemosporidian communities throughout their range, and vice-versa. More surveys are needed to elucidate mechanisms that underpin spatial patterns of diversity in this complex multi-host multi-parasite system. We sought to understand how and why a community of avian haemosporidian parasites varies in abundance and composition across elevational transects in eight sky islands in southwestern North America. We tested whether bird community composition, environment, or geographic distance explain haemosporidian parasite species turnover in a widespread host that harbors a diverse haemosporidian community, the Audubon's Warbler (Setophaga auduboni). We tested predictors of infection using generalized linear models, and predictors of bird and parasite community dissimilarity using generalized dissimilarity modeling. Predictors of infection differed by parasite genus: Parahaemoproteus was predicted by elevation and climate, Leucocytozoon varied idiosyncratically among mountains, and Plasmodium was unpredictable, but rare. Parasite turnover was nearly three-fold higher than bird turnover and was predicted by elevation, climate, and bird community composition, but not geographic distance. Haemosporidian communities vary strikingly at fine spatial scales (hundreds of kilometers), across which the bird community varies only subtly. The finer scale of turnover among parasites implies that their ranges may be smaller than those of their hosts. Avian host species should encounter different parasite species in different parts of their ranges, resulting in spatially varying selection on host immune systems. The fact that parasite turnover was predicted by bird turnover, even when considering environmental characteristics, implies that host species or their phylogenetic history plays a role in determining which parasite species will be present in a community.

Geographic distributions and origins of human head lice (Pediculus humanus capitis) based on mitochondrial data.

Human head lice (Pediculus humanus capitis) are subdivided into 3 deeply divergent mitochondrial clades (Clades A, B, and C), each having unique geographical distributions. Determining the evolutionary history and geographic distribution of these mitochondrial clades can elucidate the evolutionary history of the lice as well as their human hosts. Previous data suggest that lice belonging to mitochondrial Clade B may have originated in North America or Asia; however, geographic sampling and sample sizes have been limited. With newly collected lice, we calculate the relative frequency, geographic distribution, and genetic diversity of louse mitochondrial clades to determine the geographic origin of lice belonging to Clade B. In agreement with previous studies, genetic diversity data support a North American origin of Clade B lice. It is likely that lice belonging to this mitochondrial clade recently migrated to other geographic localities, e.g., Europe and Australia, and, if not already present, may disperse further to occupy all geographic regions.

Isolation and characterization of species-specific microsatellite markers for blue and black wildebeest (Connochaetes taurinus and C. gnou).

The bluewildebeest (Connochaetes taurinus) is distributed throughout southern and east Africa while the black wildebeest (Connochaetes gnou) is endemic to South Africa and was driven to near extinction in the early 1900s due to hunting pressure and disease outbreaks. Extensive translocation of both species throughout South Africa is threatening the genetic integrity of blue and blackwilde beest. To effectively manage these species, genetic tools that can be used to detect hybrid individuals, identify genetically unique subpopulations and determine the levels of genetic diversity are required. In this study, 11 microsatellite markers were developed for wildebeest through next-generation sequencing. The microsatellite loci displayed 2.00-4.14 alleles, unbiased heterozygosity values ranged from 0.32 to 0.60 and observed heterozygosity values ranged from 0.26 to 0.52. The comparatively high level of polymorphism observed in the microsatellite markers indicates that these markers can contribute significantly to our knowledge of population genetic structure, relatedness, genetic diversity and hybridization in these species.

A rapid rate of sex-chromosome turnover and non-random transitions in true frogs.

The canonical model of sex-chromosome evolution predicts that, as recombination is suppressed along sex chromosomes, gametologs will progressively differentiate, eventually becoming heteromorphic. However, there are numerous examples of homomorphic sex chromosomes across the tree of life. This homomorphy has been suggested to result from frequent sex-chromosome turnovers, yet we know little about which forces drive them. Here, we describe an extremely fast rate of turnover among 28 species of Ranidae. Transitions are not random, but converge on several chromosomes, potentially due to genes they harbour. Transitions also preserve the ancestral pattern of male heterogamety, in line with the 'hot-potato' model of sex-chromosome transitions, suggesting a key role for mutation-load accumulation in non-recombining genomic regions. The importance of mutation-load selection in frogs might result from the extreme heterochiasmy they exhibit, making frog sex chromosomes differentiate immediately from emergence and across their entire length.