Post-Messinian evolutionary relationships across the Sicilian channel: Mitochondrial and nuclear markers link a new green toad from Sicily to African relatives

<p>Abstract</p> <p>Background</p> <p>Little attention has been paid to the consequences of the last landbridge between Africa and Sicily on Mediterranean biogeography. Previous paleontological and scarce molecular data suggest possible faunal exchange later than the well-documented landbridge in the Messinian (5.3 My); however, a possible African origin of recent terrestrial Sicilian fauna has not been thoroughly tested with molecular methods. To gain insight into the phylogeography of the region, we examine two mitochondrial and two nuclear markers (one is a newly adapted intron marker) in green toads (<it>Bufo viridis </it>subgroup) across that sea barrier, the Strait of Sicily.</p> <p>Results</p> <p>Extensive sampling throughout the western Mediterranean and North Africa revealed a deep sister relationship between Sicilian (<it>Bufo siculus </it>n.sp.) and African green toads (<it>B. boulengeri</it>) on the mitochondrial and nuclear level. Divergence times estimated under a Bayesian-coalescence framework (mtDNA control region and 16S rRNA) range from the Middle Pliocene (3.6 My) to Pleistocene (0.16 My) with an average (1.83 to 2.0 My) around the Pliocene/Pleistocene boundary, suggesting possible land connections younger than the Messinian (5.3 My). We describe green toads from Sicily and some surrounding islands as a new endemic species (<it>Bufo siculus</it>). <it>Bufo balearicus </it>occurs on some western Mediterranean islands (Corsica, Sardinia, Mallorca, and Menorca) and the Apennine Peninsula, and is well differentiated on the mitochondrial and nuclear level from <it>B. siculus </it>as well as from <it>B. viridis </it>(Laurenti), whose haplotype group reaches northeastern Italy, north of the Po River. Detection of Calabrian <it>B. balearicus </it>haplotypes in northeastern Sicily suggests recent invasion. Our data agree with paleogeographic and fossil data, which suggest long Plio-Pleistocene isolation of Sicily and episodic Pleistocene faunal exchange across the Strait of Messina. It remains unknown whether both species (<it>B. balearicus, B. siculus</it>) occur in sympatry in northern Sicily.</p> <p>Conclusion</p> <p>Our findings on green toads give the first combined mitochondrial and nuclear sequence evidence for a phylogeographic connection across the Strait of Sicily in terrestrial vertebrates. These relationships may have implications for comparative phylogeographic research on other terrestrial animals co-occurring in North Africa and Sicily.</p

Multilocus Phylogenetics of a Rapid Radiation in the Genus Thomomys (Rodentia: Geomyidae)

Species complexes undergoing rapid radiation present a challenge in molecular systematics because of the possibility that ancestral polymorphism is retained in component gene trees. Coalescent theory has demonstrated that gene trees often fail to match lineage trees when taxon divergence times are less than the ancestral effective population sizes. Suggestions to increase the number of loci and the number of individuals per taxon have been proposed; however, phylogenetic methods to adequately analyze these data in a coalescent framework are scarce.We compare two approaches to estimating lineage (species) trees using multiple individuals and multiple loci: the commonly used partitioned Bayesian analysis of concatenated sequences and a modification of a newly developed hierarchical Bayesian method (BEST) that simultaneously estimates gene trees and species trees from multilocus data. We test these approaches on a phylogeny of rapidly radiating species wherein divergence times are likely to be smaller than effective population sizes, and incomplete lineage sorting is known, in the rodent genus, Thomomys.We use seven independent noncoding nuclear sequence loci (total ~4300 bp) and between 1 and 12 individuals per taxon to construct a phylogenetic hypothesis for eight Thomomys species. The majority-rule consensus tree from the partitioned concatenated analysis included 14 strongly supported bipartitions, corroborating monophyletic species status of five of the eight named species. The BEST tree strongly supported only the split between the two subgenera and showed very low support for any other clade. Comparison of both lineage trees to individual gene trees revealed that the concatenation method appears to ignore conflicting signals among gene trees, whereas the BEST tree considers conflicting signals and downweights support for those nodes. Bayes factor analysis of posterior tree distributions from both analyses strongly favor the model underlying the BEST analysis. This comparison underscores the risks of overreliance on results from concatenation, and ignoring the properties of coalescence, especially in cases of recent, rapid radiations

Multifunctional TiO2 coatings for Cultural Heritage

Environmental pollution arising from industrial implants and urban factors is constantly increasing,causing aesthetical and durability concerns to urban structures exposed to the atmosphere.Nanometric titanium dioxide has become a promising photocatalytic material owing to its ability tocatalyze the complete degradation of many organic contaminants and environmental toxins.This work deals with the preparation system that could take advantage of functionalized buildingmaterials in order to improve the quality of urban surfaces, with particular regard to Cultural Heritage.TiO2-containing photoactive materials represent an appealing way to create self-cleaning surfaces, thuslimiting maintenance costs, and to promote the degradation of polluting agents. Titanium dioxide dispersedin polymeric matrices can represent a coating technology with hydrophobic, consolidating andbiocidal properties, suitable for the restoration of building stone materials belonging to our CulturalHeritage. Mixtures were tested on marble and limestone substrates. Capillary water absorption, simulatedsolar aging, colorimetric and contact angle measurements have been performed to evaluate theirproperties

Nano-TiO2 coatings for cultural heritage protection: The role of the binder on hydrophobic and self-cleaning efficacy

Nano-sized titanium dioxide has demonstrated its efficiency in many application fields thanks to its photocatalytic features that provide self-cleaning properties to the materials with simple and non-expensive procedures. For this reason, it has been successfully used also for the practice of restoration of stone built heritage. However, some aspects are still unresolved and need to be further investigated, such as the method for binding these particles to stone surfaces. In this work, nano-TiO2 was combined with three different binders and applied on two stone substrates, namely the Carrara marble and the Noto calcarenite, two lithotypes extensively used in built heritage. The performance of all tested coatings was evaluated by scanning electron microscopy (SEM), roughness measurements, capillary water absorption test, static contact angle calculation, colorimetric measurements, UV aging and self-cleaning test. Results suggested the key role of interaction between coating and stone surface in terms of penetration of the product, hydrophobicity, variations of surface roughness and durability, which define the performance of the coatings. Specifically, among the three tested products, the best behaviour in terms of hydrophobicity, durability and self-cleaning properties was shown by both the acrylic (Fosbuild) and fluorinated (Akeograd P) suspensions. Conversely, the Paraloid id B72 - TiO2 mixture led to an intense superficial alteration of both stones and showed scarce water-repellent and photo-degrading effect.This research was funded by POR Calabria FESR project “NANOPROTECH” (NANO PROtection TEchnology for Cultural Heritage).Peer reviewe

Post-Messinian evolutionary relationships across the Sicilian channel: Mitochondrial and nuclear markers link a new green toad from Sicily to African relatives-0

are written above nodes, * indicates a value of 100% posterior probability. Each branch label in the d-loop tree contains the sample number and the major locality information. (Note that each label on the nuclear trees corresponds to the exactly horizontally opposite label of the d-loop tree. ("B." in the d-loop tree stands for ; all samples labeled "B." were sequenced by A. Sicilia; all "Bufo" samples were sequenced by M. Stöck).<p><b>Copyright information:</b></p><p>Taken from "Post-Messinian evolutionary relationships across the Sicilian channel: Mitochondrial and nuclear markers link a new green toad from Sicily to African relatives"</p><p>http://www.biomedcentral.com/1471-2148/8/56</p><p>BMC Evolutionary Biology 2008;8():56-56.</p><p>Published online 23 Feb 2008</p><p>PMCID:PMC2276203.</p><p></p

Post-Messinian evolutionary relationships across the Sicilian channel: Mitochondrial and nuclear markers link a new green toad from Sicily to African relatives-2

are written above nodes, * indicates a value of 100% posterior probability. Each branch label in the d-loop tree contains the sample number and the major locality information. (Note that each label on the nuclear trees corresponds to the exactly horizontally opposite label of the d-loop tree. ("B." in the d-loop tree stands for ; all samples labeled "B." were sequenced by A. Sicilia; all "Bufo" samples were sequenced by M. Stöck).<p><b>Copyright information:</b></p><p>Taken from "Post-Messinian evolutionary relationships across the Sicilian channel: Mitochondrial and nuclear markers link a new green toad from Sicily to African relatives"</p><p>http://www.biomedcentral.com/1471-2148/8/56</p><p>BMC Evolutionary Biology 2008;8():56-56.</p><p>Published online 23 Feb 2008</p><p>PMCID:PMC2276203.</p><p></p

Post-Messinian evolutionary relationships across the Sicilian channel: Mitochondrial and nuclear markers link a new green toad from Sicily to African relatives-1

<p><b>Copyright information:</b></p><p>Taken from "Post-Messinian evolutionary relationships across the Sicilian channel: Mitochondrial and nuclear markers link a new green toad from Sicily to African relatives"</p><p>http://www.biomedcentral.com/1471-2148/8/56</p><p>BMC Evolutionary Biology 2008;8():56-56.</p><p>Published online 23 Feb 2008</p><p>PMCID:PMC2276203.</p><p></p