Preserving the impossible: conservation of soft-sediment hominin footprint sites and strategies for three-dimensional digital data capture.

Human footprints provide some of the most publically emotive and tangible evidence of our ancestors. To the scientific community they provide evidence of stature, presence, behaviour and in the case of early hominins potential evidence with respect to the evolution of gait. While rare in the geological record the number of footprint sites has increased in recent years along with the analytical tools available for their study. Many of these sites are at risk from rapid erosion, including the Ileret footprints in northern Kenya which are second only in age to those at Laetoli (Tanzania). Unlithified, soft-sediment footprint sites such these pose a significant geoconservation challenge. In the first part of this paper conservation and preservation options are explored leading to the conclusion that to 'record and digitally rescue' provides the only viable approach. Key to such strategies is the increasing availability of three-dimensional data capture either via optical laser scanning and/or digital photogrammetry. Within the discipline there is a developing schism between those that favour one approach over the other and a requirement from geoconservationists and the scientific community for some form of objective appraisal of these alternatives is necessary. Consequently in the second part of this paper we evaluate these alternative approaches and the role they can play in a 'record and digitally rescue' conservation strategy. Using modern footprint data, digital models created via optical laser scanning are compared to those generated by state-of-the-art photogrammetry. Both methods give comparable although subtly different results. This data is evaluated alongside a review of field deployment issues to provide guidance to the community with respect to the factors which need to be considered in digital conservation of human/hominin footprints

Multigene Phylogeny of Choanozoa and the Origin of Animals

Animals are evolutionarily related to fungi and to the predominantly unicellular protozoan phylum Choanozoa, together known as opisthokonts. To establish the sequence of events when animals evolved from unicellular ancestors, and understand those key evolutionary transitions, we need to establish which choanozoans are most closely related to animals and also the evolutionary position of each choanozoan group within the opisthokont phylogenetic tree. Here we focus on Ministeria vibrans, a minute bacteria-eating cell with slender radiating tentacles. Single-gene trees suggested that it is either the closest unicellular relative of animals or else sister to choanoflagellates, traditionally considered likely animal ancestors. Sequencing thousands of Ministeria protein genes now reveals about 14 with domains of key significance for animal cell biology, including several previously unknown from deeply diverging Choanozoa, e.g. domains involved in hedgehog, Notch and tyrosine kinase signaling or cell adhesion (cadherin). Phylogenetic trees using 78 proteins show that Ministeria is not sister to animals or choanoflagellates (themselves sisters to animals), but to Capsaspora, another protozoan with thread-like (filose) tentacles. The Ministeria/Capsaspora clade (new class Filasterea) is sister to animals and choanoflagellates, these three groups forming a novel clade (filozoa) whose ancestor presumably evolved filose tentacles well before they aggregated as a periciliary collar in the choanoflagellate/sponge common ancestor. Our trees show ichthyosporean choanozoans as sisters to filozoa; a fusion between ubiquitin and ribosomal small subunit S30 protein genes unifies all holozoa (filozoa plus Ichthyosporea), being absent in earlier branching eukaryotes. Thus, several successive evolutionary innovations occurred among their unicellular closest relatives prior to the origin of the multicellular body-plan of animals

Proteome-Wide Search Reveals Unexpected RNA-Binding Proteins in Saccharomyces cerevisiae

The vast landscape of RNA-protein interactions at the heart of post-transcriptional regulation remains largely unexplored. Indeed it is likely that, even in yeast, a substantial fraction of the regulatory RNA-binding proteins (RBPs) remain to be discovered. Systematic experimental methods can play a key role in discovering these RBPs - most of the known yeast RBPs lack RNA-binding domains that might enable this activity to be predicted. We describe here a proteome-wide approach to identify RNA-protein interactions based on in vitro binding of RNA samples to yeast protein microarrays that represent over 80% of the yeast proteome. We used this procedure to screen for novel RBPs and RNA-protein interactions. A complementary mass spectrometry technique also identified proteins that associate with yeast mRNAs. Both the protein microarray and mass spectrometry methods successfully identify previously annotated RBPs, suggesting that other proteins identified in these assays might be novel RBPs. Of 35 putative novel RBPs identified by either or both of these methods, 12, including 75% of the eight most highly-ranked candidates, reproducibly associated with specific cellular RNAs. Surprisingly, most of the 12 newly discovered RBPs were enzymes. Functional characteristics of the RNA targets of some of the novel RBPs suggest coordinated post-transcriptional regulation of subunits of protein complexes and a possible link between mRNA trafficking and vesicle transport. Our results suggest that many more RBPs still remain to be identified and provide a set of candidates for further investigation

Use of marine fauna and tool stones in the south of Buenos Aires Province (Argentina) during the Middle and Late Holocene

The exploitation of coastal and marine resources by hunter-gatherers in the south of Buenos Aires Province (Argentina) during the Mid-Late Holocene was examined through the analysis of faunal and lithic evidence in the following archaeological sites: El Americano II and Barrio Las Dunas (Mid-Late Holocene), both located in coastal sand dunes, Puente de Fierro (Late Holocene), located in a wetland distant 7 km from the seashore, Paso Vanoli, located 13 km from the seashore, and Paso Mayor YI S1 (Mid-Late Holocene), located in a fluvial environment 41 km from the seashore. The evidence suggests that, during the Mid-Holocene, in the coastal sites, hunter-gatherers used several marine vertebrates (e.g. pinnipeds and fishes—Pogonias cromis-), whereas in the inland sites, they only transported mollusks and coastal pebbles. In the Late Holocene, in the sites located a few kilometers from the coast, hunter-gatherers carried only selected parts of pinnipeds as well as mollusks and coastal pebbles. Pinnipeds represented a low proportion of the faunal remains. In contrast, in sites far away from the Atlantic coast, hunter-gatherers carried only stones and mollusks. We propose that although the Atlantic coast in the study area was regularly visited by hunter-gatherers all along the Holocene, the importance of marine food decreased during the Late Holocene, whereas the importance of coastal tool stones and mollusks continued.Fil: Frontini, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Humanidades; ArgentinaFil: Bayón, María Cristina. Universidad Nacional del Sur. Departamento de Humanidades; Argentin

Fish Capture Strategies in Atlantic Littoral of Monte Hermoso District (Pampean Region Argentina) During Middle Holocene

Pampean hunter-gatherers marine fish capture strategies during the Middle Holocene are analyzed based on fish remains, lithic technology, paleoenviron-mental reconstructions and fish ethology. Barrio Las Dunas site and El Americano II site archaeofaunistic record evidence of the exploitation of estuarine-dependent fish species: Pogonias cromis and Micropogonias furnieri. Lithic assemblages comprise scarce lithic weights corresponding to net weights and line weights that evidence the use of two fishing gears. It is concluded that the study sector was a hunter-gatherers preferential place for marine resource acquisition due to its palaeoenvironmental conditions.Fil: Frontini, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur; ArgentinaFil: Bayón, María Cristina. Universidad Nacional del Sur. Departamento de Humanidades. Area de Historia; ArgentinaFil: Vecchi, Rodrigo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Humanidades. Area de Historia; Argentin

Phylogeography of Cnesterodon decemmaculatus (Cyprinodontiformes: poeciilidae) in Southern Pampas, Argentina: ancient versus recent patterns in freshwater fishes

The Southern Pampean Area includes the southernmost limit of the Brazilian subregion and represents an interesting model to study how evolution of the landscape has affected the distribution of freshwater fishes in time and space. The hydrogeographic pattern of the region results from a combination of factors including climatic and sea level changes occurred since the Miocene and extending into the Quaternary. The hydrologic basins of this region are isolated, and have a similar ichthyological composition among them. Here we use a phylogeographic approach to infer how paleoclimatic changes affected the distribution of genetic variation in the populations of freshwater fishes. We analyzed the control region of mtDNA of Cnesterodon decemmaculatus and compared it with published data for the species Jenynsia multidentata and Corydoras paleatus in the same area. Cnesterodon decemmaculatus showed two main haplotypes with scarce divergence and wide geographical distribution within the area. The low divergence found between the Cnesterodon decemmaculatus haplotypes and the results obtained in the demographic analyses could suggest that the presence of this species in the area have a recent demographic history. These results are in contrast with the pattern reported for Jenynsia multidentata and Corydoras paleatus, where data suggest an ancient history in the area. The incongruence in the observed phylogeographical patterns could be due to the different ecological requirements of each species, and to the various responses of them to the environmental conditions resulting from geologic and paleoclimatic changes occurred in the region during the Late Quaternary.Fil: Bruno, María Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Genética; ArgentinaFil: Mapelli, Fernando Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Ecofisiología; ArgentinaFil: Casciotta, Jorge Rafael. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico Zoología Vertebrados; ArgentinaFil: Almirón, Adriana Edith. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico Zoología Vertebrados; ArgentinaFil: Lizarralde, Marta Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentin