Polar diversity of the Tardigrada: A combined morphological / molecular approach.

http://www.uam.es/otros/cn-scar//SCAR_IASC_IPY/pdf/17167.pdfPOLAR DIVERSITY OF THE TARDIGRADA: A COMBINED MORPHOLOGICAL / MOLECULAR APPROACH C.J. Sands1 , S.J. McInnes1 , N.J. Marley2 , W.P. Goodall-Copestake1 , P. Convey1 , L. Linse1 1 - Natural Environment Research Council, British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, United Kingdom 2 - Marine Biology and Ecology Research Centre, University of Plymouth, Drake Circus, Plymouth, PL4 8AA, United Kingdom [email protected] Examining the spatial distributions of organisms can provide information regarding their evolutionary history. We are investigating the origins and the processes that influence the contemporary distribution and diversity of Antarctic terrestrial biota. Tardigrades were chosen as a model group, as representatives are found in a diverse range of habitats across the Antarctic continent and sub-Antarctic islands. Our investigations involving approximately 400 individuals and 3 genes have identified systematic complexity requiring attention in order to prevent confounding the biogeographic signal. To overcome the challenges inherent in taxonomic and molecular work on very tiny animals (meiofauna), we have developed a protocol that allows efficient sample extraction and identification without interfering with downstream molecular processes. Our protocol provides joint morphological/molecular assessment of tardigrade taxonomy at the level of the individual that has resulted in identification of numerous cryptic species, cryptic genera and even cryptic families. To resolve polyphyly at the family level we have proposed three superfamilies that are strongly supported by molecular analyses. Here we present a systematic revision of the phylum Tardigrada along with some novel insights regarding Antarctic tardigrade biogeography

Marine plastics threaten giant Atlantic Marine Protected Areas.

There has been a recent shift in global perception of plastics in the environment, resulting in a call for greater action. Science and the popular media have highlighted plastic as an increasing stressor [1,2]. Efforts have been made to confer protected status to some remote locations, forming some of the world's largest Marine Protected Areas, including several UK overseas territories. We assessed plastic at these remote Atlantic Marine Protected Areas, surveying the shore, sea surface, water column and seabed, and found drastic changes from 2013-2018. Working from the RRS James Clark Ross at Ascension, St. Helena, Tristan da Cunha, Gough and the Falkland Islands (Figure 1A), we showed that marine debris on beaches has increased more than 10 fold in the past decade. Sea surface plastics have also increased, with in-water plastics occurring at densities of 0.1 items m-3; plastics on seabeds were observed at ≤ 0.01 items m-2. For the first time, beach densities of plastics at remote South Atlantic sites approached those at industrialised North Atlantic sites. This increase even occurs hundreds of meters down on seamounts. We also investigated plastic incidence in 2,243 animals (comprising 26 species) across remote South Atlantic oceanic food webs, ranging from plankton to seabirds. We found that plastics had been ingested by primary consumers (zooplankton) to top predators (seabirds) at high rates. These findings suggest that MPA status will not mitigate the threat of plastic proliferation to this rich, unique and threatened biodiversity

Comparative Analysis of Begonia Plastid Genomes and Their Utility for Species-Level Phylogenetics

Recent, rapid radiations make species-level phylogenetics difficult to resolve. We used a multiplexed, high-throughput sequencing approach to identify informative genomic regions to resolve phylogenetic relationships at low taxonomic levels in Begonia from a survey of sixteen species. A long-range PCR method was used to generate draft plastid genomes to provide a strong phylogenetic backbone, identify fast evolving regions and provide informative molecular markers for species-level phylogenetic studies in Begonia

¿Los agricultores reducen la diversidad genética cuando domestican árboles tropicales? Un estudio de caso de la Amazonia

Los ecosistemas agroforestales pueden ser un recurso importante para la conservación y el uso sostenible de los árboles tropicales, pero se sabe poco de la diversidad genética que contienen. Inga edulis , un árbol frutal autóctono muy extendido en América del Sur, se utiliza como modelo para evaluar el mantenimiento de la diversidad genética en cinco rodales plantados frente a cinco naturales en la Amazonía peruana. El análisis de cinco loci SSR (repetición de secuencia simple) indicó una variación alélica más baja en los rodales plantados [riqueza alélica corregida media 31,3 (plantada) y 39,3 (natural), P = 0,009]. Las preocupaciones sobre la erosión genética en los rodales de árboles amazónicos plantados parecen válidas, aunque la variación alélica en la finca es todavía relativamente alta.Agroforestry ecosystems may be an important resource for conservation and sustainable use of tropical trees, but little is known of the genetic diversity they contain. Inga edulis , a widespread indigenous fruit tree in South America, is used as a model to assess the maintenance of genetic diversity in five planted vs. five natural stands in the Peruvian Amazon. Analysis of five SSR (simple sequence repeat) loci indicated lower allelic variation in planted stands [mean corrected allelic richness 31.3 (planted) and 39.3 (natural), P = 0.009]. Concerns regarding genetic erosion in planted Amazonian tree stands appear valid, although allelic variation on?farm is still relatively high

On the comparison of population-level estimates of haplotype and nucleotide diversity: a case study using the gene cox1 in animals

Estimates of genetic diversity represent a valuable resource for biodiversity assessments and are increasingly used to guide conservation and management programs. The most commonly reported estimates of DNA sequence diversity in animal populations are haplotype diversity (h) and nucleotide diversity (π) for the mitochondrial gene cytochrome c oxidase subunit I (cox1). However, several issues relevant to the comparison of h and π within and between studies remain to be assessed. We used population-level cox1 data from peer-reviewed publications to quantify the extent to which data sets can be re-assembled, to provide a standardized summary of h and π estimates, to explore the relationship between these metrics and to assess their sensitivity to under-sampling. Only 19 out of 42 selected publications had archived data that could be unambiguously re-assembled; this comprised 127 population-level data sets (ngreater than or equal to15) from 23 animal species. Estimates of h and π were calculated using a 456-base region of cox1 that was common to all the data sets (median h=0.70130, median π=0.00356). Non-linear regression methods and Bayesian information criterion analysis revealed that the most parsimonious model describing the relationship between the estimates of h and π was π=0.0081h2. Deviations from this model can be used to detect outliers due to biological processes or methodological issues. Subsampling analyses indicated that samples of n>5 were sufficient to discriminate extremes of high from low population-level cox1 diversity, but samples of ngreater than or equal to25 are recommended for greater accuracy

Data from: Insights into the origin and distribution of biodiversity in the Brazilian Atlantic forest hotspot: a statistical phylogeographic study using a low-dispersal organism

The relative importance of the processes that generate and maintain biodiversity is a major and controversial topic in evolutionary biology with large implications for conservation management. The Atlantic Forest of Brazil, one of the world's richest biodiversity hotspots, is severely damaged by human activities. To carry out an efficient conservation policy, a good understanding of spatial and temporal biodiversity patterns and their underlying evolutionary mechanisms is required. With this aim, we performed a comprehensive phylogeographic study using a low-dispersal organism, the land planarian species Cephaloflexa bergi (Platyhelminthes, Tricladida). Applying a multi-locus DNA sequence variation approach under the ABC framework we evaluated two scenarios proposed to explain the diversity of SAF region. We found that most sampled localities harbour high levels of genetic diversity, with lineages sharing old common ancestors that predate the Pleistocene. Remarkably, we detected the molecular hallmark of the isolation-by-distance effect and little evidence of a recent colonization of SAF localities; some populations nevertheless might result from very recent secondary contacts. We conclude that extant SAF biodiversity originated and has been shaped by complex interactions between ancient geological events and more recent evolutionary processes, while Pleistocene climate changes would have a minor influence in generating present day diversity. We also demonstrate that land planarians are an advantageous biological model for making phylogeographic and, particularly, fine-scale evolutionary inferences, and propose appropiate conservation policies