Agregación de autoinmunidad en familias extremas con Síndrome de Sjogren: una aproximación a la medicina personalizada

Objetivo: investigar la agregación de autoinmunidad en familiares en primer grado (FPG) de probandos con Síndrome de Sjogren (SS) con poliautoinmunidad y autoinmunidad familiar. Metodología: estudio de corte transversal en el cual se incluyeron 14 familias de mujeres con SS. Se realizó un análisis genético a través del cálculo de riesgos relativos para cada enfermedad autoinmune (EAI). La agregación familiar se calculó para los FPG, teniendo en cuenta la prevalencia de la enfermedad en cada familia y en la población general. Resultados: Se analizaron un total de 112 individuos, con una media de edad de 51.7 años ± 12.9. Veintidós individuos de los FPG tuvieron al menos una EAI (28.2%). La prevalencia de poliautoinmunidad fue del 93% y 6.4% en probandos y FPG, respectivamente. Se observaron valores que soportaron la agregación familiar para varias EAIs, entre ellas púrpura trombocitopénica idiopática, granulomatosis con poliangeiitis, síndrome antifosfolipídico, lupus eritematoso sistémico y artritis reumatoide. Discusión: estos resultados indican que las EAIs se agregan entre familias con SS, sugiriendo un origen común entre ellas. La elección de fenotipos clínicamente relevantes representa una nueva aproximación a la medicina personalizada en autoinmunidad.

Alteraciones en el material genético de pintores de carros expuestos a solventes orgánicos en una localidad de Bogotá

Los solventes orgánicos son sustancias químicas que por sus propiedades físico-químicas son fácilmente inhalados o absorbidos por la piel, pueden causar daños de diversa índole en la salud. En Colombia existen normas que contemplan las medidas de protección, sin embargo persiste la informalidad en el sector de pintores de autos, por lo cual los trabajadores expuestos, a largo plazo pueden ver afectada su salud. En este estudio se analizó la relación entre individuos expuestos laboralmente a los solventes orgánicos versus no expuestos con respecto a la longitud de sus telómeros y formación de fragilidades. Se emplearon muestras de sangre extraídas por venopunción, recolectada en dos tubos: uno con Heparina, destinado al cultivo de linfocitos, para obtener cromosomas metafásicos y evaluar en ellos la presencia de fragilidades; el otro tubo con EDTA, fue empleado para la extracción de ADN y se utilizó para obtener los valores de longitud telomérica mediante la técnica de PCR cuantitativa. Los análisis estadísticos se realizaron aplicando la prueba de rangos de Wilcoxon, en el caso de la presencia de fragilidades se analizó la razón No.Fragilidades/No.Metafases, aplicando el método de Wilcoxon se encontró que existe diferencia estadísticamente significativa entre expuestos y no expuestos (p = 0,036), en donde los expuestos presentan mayor frecuencia de fragilidades. Por otra parte el valor relativo de longitud telomérica del grupo de expuestos fue mayor que el observado en el grupo de no expuestos, esta diferencia fue estadísticamente significativa (Wilcoxon, p = 0.002).

Geographical variation in the clouded leopard, Neofelis nebulosa, reveals two species

The clouded leopard, Neofelis nebulosa, is an endangered semiarboreal felid with a wide distribution in tropical forests of southern and southeast Asia, including the islands of Sumatra and Borneo in the Indonesian archipelago [1]. In common with many larger animal species, it displays morphological variation within its wide geographical range and is currently regarded as comprising of up to four subspecies [2-4]. It is widely recognized that taxonomic designation has a major impact on conservation planning and action [5-8]. Given that the last taxonomic revision was made over 50 years ago [2], a more detailed examination of geographical variation is needed. We describe here the results of a morphometric analysis of the pelages of 57 clouded leopards sampled throughout the species' range. We conclude that there are two distinct morphological groups, which differ primarily in the size of their cloud markings. These results are supported by a recent genetic analysis [9]. On that basis, we give diagnoses for the distinction of two species, one in mainland Asia (N. nebulosa) and the other in Indonesia (N. diardi). The implications for conservation that arise from this new taxonomic arrangement are discussed.

The development of ISSR-derived SCAR markers around the Seasonal Flowering Locus (SFL) in fragaria vesca

Fragaria vesca is a short-lived perennial with a seasonal-flowering habit. Seasonality of flowering is widespread in the Rosaceae and is also found in the majority of temperate polycarpic perennials. Genetic analysis has shown that seasonal flowering is controlled by a single gene in F. vesca, the SEASONAL FLOWERING LOCUS (SFL). Here, we report progress towards the marker-assisted selection and positional cloning of SFL, in which three ISSR markers linked to SFL were converted to locus-specific sequence-characterized amplified region (SCAR1–SCAR3) markers to allow large-scale screening of mapping progenies. We believe this is the first study describing the development of SCAR markers from ISSR profiles. The work also provides useful insight into the nature of polymorphisms generated by the ISSR marker system. Our results indicate that the ISSR polymorphisms originally detected were probably caused by point mutations in the positions targeted by primer anchors (causing differential PCR failure), by indels within the amplicon (leading to variation in amplicon size) and by internal sequence differences (leading to variation in DNA folding and so in band mobility). The cause of the original ISSR polymorphism was important in the selection of appropriate strategies for SCAR-marker development. The SCAR markers produced were mapped using a F. vesca f. vesca × F. vesca f. semperflorens testcross population. Marker SCAR2 was inseparable from the SFL, whereas SCAR1 mapped 3.0 cM to the north of the gene and SCAR3 1.7 cM to its south.

Mining gene networks with application to GAW15 problem 1

The genetic analysis workshop 15 (GAW15) problem 1 contained baseline expression levels of 8793 genes in immortalised B cells from 194 individuals in 14 Centre d’Etude du Polymorphisme Humane (CEPH) Utah pedigrees. Previous analysis of the data showed linkage and association and evidence of substantial individual variations. In particular, correlation was examined on expression levels of 31 genes and 25 target genes corresponding to two master regulatory regions. In this analysis, we apply Bayesian network analysis to gain further insight into these findings. We identify strong dependences and therefore provide additional insight into the underlying relationships between the genes involved. More generally, the approach is expected to be applicable for integrated analysis of genes on biological pathways.

Adaptive divergence and speciation among sexual and pseudoviviparous populations of Festuca

Pseudovivipary is an environmentally induced flowering abnormality in which vegetative shoots replace seminiferous (sexual) inflorescences. Pseudovivipary is usually retained in transplantation experiments, indicating that the trait is not solely induced by the growing environment. Pseudovivipary is the defining characteristic of Festuca vivipara, and arguably the only feature separating this species from its closest seminiferous relative, Festuca ovina. We performed phylogenetic and population genetic analysis on sympatric F. ovina and F. vivipara samples to establish whether pseudovivipary is an adaptive trait that accurately defines the separation of genetically distinct Festuca species. Chloroplast and nuclear marker-based analyses revealed that variation at a geographical level can exceed that between F. vivipara and F. ovina. We deduced that F. vivipara is a recent species that frequently arises independently within F. ovina populations and has not accumulated significant genetic differentiation from its progenitor. We inferred local gene flow between the species. We identified one amplified fragment length polymorphism marker that may be linked to a pseudovivipary-related region of the genome, and several other markers provide evidence of regional local adaptation in Festuca populations. We conclude that F. vivipara can only be appropriately recognized as a morphologically and ecologically distinct species; it lacks genetic differentiation from its relatives. This is the first report of a ‘failure in normal flowering development’ that repeatedly appears to be adaptive, such that the trait responsible for species recognition constantly reappears on a local basis.

Integration of retrotransposons-based markers in a linkage map of barley

A deeper understanding of random markers is important if they are to be employed for a range of objectives. The sequence specific amplified polymorphism (S-SAP) technique is a powerful genetic analysis tool which exploits the high copy number of retrotransposon long terminal repeats (LTRs) in the plant genome. The distribution and inheritance of S-SAP bands in the barley genome was studied using the Steptoe × Morex (S × M) double haploid (DH) population. Six S-SAP primer combinations generated 98 polymorphic bands, and map positions were assigned to all but one band. Eight putative co-dominant loci were detected, representing 16 of the mapped markers. Thus at least 81 of the mapped S-SAP loci were dominant. The markers were distributed along all of the seven chromosomes and a tendency to cluster was observed. The distribution of S-SAP markers over the barley genome concurred with the knowledge of the high copy number of retrotransposons in plants. This experiment has demonstrated the potential for the S-SAP technique to be applied in a range of analyses such as genetic fingerprinting, marker assisted breeding, biodiversity assessment and phylogenetic analyses.

The biosurfactant viscosin produced by Pseudomonas fluorescens SBW25 aids spreading motility and plant growth promotion

Food security depends on enhancing production and reducing loss to pests and pathogens. A promising alternative to agrochemicals is the use of plant growth-promoting rhizobacteria (PGPR), which are commonly associated with many, if not all, plant species. However, exploiting the benefits of PGPRs requires knowledge of bacterial function and an in-depth understanding of plant-bacteria associations. Motility is important for colonization efficiency and microbial fitness in the plant environment, but the mechanisms employed by bacteria on and around plants are not well understood. We describe and investigate an atypical mode of motility in Pseudomonas fluorescens SBW25 that was revealed only after flagellum production was eliminated by deletion of the master regulator fleQ. Our results suggest that this ‘spidery spreading’ is a type of surface motility. Transposon mutagenesis of SBW25ΔfleQ (SBW25Q) produced mutants, defective in viscosin production, and surface spreading was also abolished. Genetic analysis indicated growth-dependency, production of viscosin, and several potential regulatory and secretory systems involved in the spidery spreading phenotype. Moreover, viscosin both increases efficiency of surface spreading over the plant root and protects germinating seedlings in soil infected with the plant pathogen Pythium. Thus, viscosin could be a useful target for biotechnological development of plant growth promotion agents.

Alterations in predicted regulatory and coding regions of the sterol 14α-demethylase gene (CYP51) confer decreased azole sensitivity in the oilseed rape pathogen Pyrenopeziza brassicae

The incidence and severity of light leaf spot epidemics caused by the ascomycete fungus Pyrenopeziza brassicae on UK oilseed rape crops is increasing. The disease is currently controlled by a combination of host resistance, cultural practices and fungicide applications. We report decreases in sensitivities of modern UK P. brassicae isolates to the azole (imidazole and triazole) class of fungicides. By cloning and sequencing the P. brassicae CYP51 (PbCYP51) gene, encoding the azole target sterol 14α-demethylase, we identified two non-synonymous mutations encoding substitutions G460S and S508T associated with reduced azole sensitivity. We confirmed the impact of the encoded PbCYP51 changes on azole sensitivity and protein activity by heterologous expression in a Saccharomyces cerevisiae mutant YUG37::erg11 carrying a controllable promoter of native CYP51 expression. In addition, we identified insertions in the predicted regulatory regions of PbCYP51 in isolates with reduced azole sensitivity. The presence of these insertions was associated with enhanced transcription of PbCYP51 in response to sub-inhibitory concentrations of the azole fungicide tebuconazole. Genetic analysis of in vitro crosses of sensitive and resistant isolates confirmed the impact of PbCYP51 alterations in coding and regulatory sequences on a reduced sensitivity phenotype, as well as identifying a second major gene at another locus contributing to resistance in some isolates. The least sensitive field isolates carry combinations of upstream insertions and non-synonymous mutations, suggesting PbCYP51 evolution is on-going and the progressive decline in azole sensitivity of UK P. brassicae populations will continue. The implications for the future control of light leaf spot are discussed.

Fighting in fig wasps: do males avoid killing brothers or do they never meet them?

1. In many fig wasp species, armoured wingless males regularly engage in lethal fights for access to females inside figs, which act as discrete mating patches. 2. Kin selection generally opposes killing brothers, because their reproductive success provides indirect genetic benefits (inclusive fitness). However, siblicide may be avoided if (i) brothers do not occur in the same figs, or (ii) males avoid fighting brothers in the same fig. Alternatively, (iii) siblicide may occur because intense mate competition between brothers at the local scale overcomes kin selection effects, or (iv) males do not recognise kin. 3. A fig may also contain wasps from other closely related species and it is not known if males also fight with these individuals. 4. Nine microsatellite loci were used in the first genetic analysis of fighting in fig wasps. We assigned species and sibling identities to males and tested alternative fighting scenarios for three Sycoscapter wasp species in figs of Ficus rubiginosa. 5. Approximately 60% of figs contained males frommore than one Sycoscapter species and approximately 80% of fights were between conspecifics, but a surprising 20% were between heterospecific males. 6.Within species, fewfigs contained brothers, suggesting that females typically lay one son per fig. Overall, most males do not compete with brothers and all fights observed were between unrelated males. Key words:Competition, fighting, genetics, kin selection, microsatellites, relatedness.

PODOCARPUS SP.PL. REFUGIA IN BRAZIL`S ATLANTIC FOREST: ANALYSING THE PAST TO IMPROVE FUTURE PROTECTION

The Atlantic rainforest has the second highest biodiversity in Brazil. It has been shrinking rapidly in area as a result of intensive deforestation, and only 7% of the original cover now remains, as isolated patches or in ecological reserves. In order to obtain new information on the distribution of the Atlantic rainforest during the Quaternary, we examined herbarium data to locate relevant populations and extracted DNA from fresh leaves from 26 populations. The present-day distribution of endemic Podocarpus populations shows that they are widely dispersed across eastern Brazil, and that the expansion of Podocarpus recorded in single Amazonian pollen records may have originated from either western or eastern populations. Genetic analysis enabled us to determine the boundaries of their regional expansion: northern and central populations of P. sellowii appeared between 5 degrees and 15 degrees S some 16,000 years ago; populations of P lambertii or sellowii have appeared between 15 degrees and 23 degrees S at different times since the last glaciation at least; and P lambertii appeared between 23 degrees and 30 degrees S during the recent expansion of Araucaria forests. The combination of botanical, pollen, and molecular analyses proved to be a rapid means of inferring distribution boundaries for sparse populations and their regional evolution within tropical ecosystems. Today the rainforest refugia we identified have become hotspots that are crucial to the survival of the Atlantic forest under unfavourable climatic conditions and, as such, offer the only possible opportunity for this type of forest to expand in the event of future climate change.

Successful carnivore identification with faecal DNA across a fragmented Amazonian landscape

The use of scat surveys to obtain DNA has been well documented in temperate areas, where DNA preservation may be more effective than in tropical forests. Samples obtained in the tropics are often exposed to high humidity, warm temperatures, frequent rain and intense sunlight, all of which can rapidly degrade DNA. Despite these potential problems, we demonstrate successful mtDNA amplification and sequencing for faeces of carnivores collected in tropical conditions and quantify how sample condition and environmental variables influence the success of PCR amplification and species identification. Additionally, the feasibility of genotyping nuclear microsatellites from jaguar (Panthera onca) faeces was investigated. From October 2007 to December 2008, 93 faecal samples were collected in the southern Brazilian Amazon. A total of eight carnivore species was successfully identified from 71% of all samples obtained. Information theoretic analysis revealed that the number of PCR attempts before a successful sequence was an important negative predictor across all three responses (success of species identification, success of species identification from the first sequence and PCR amplification success), whereas the relative importance of the other three predictors (sample condition, season and distance from forest edge) varied between the three responses. Nuclear microsatellite amplification from jaguar faeces had lower success rates (15-44%) compared with those of the mtDNA marker. Our results show that DNA obtained from faecal samples works efficiently for carnivore species identification in the Amazon forest and also shows potential for nuclear DNA analysis, thus providing a valuable tool for genetic, ecological and conservation studies.

Skull Modularity in Neotropical Marsupials and Monkeys: Size Variation and Evolutionary Constraint and Flexibility

An organism is built through a series of contingent factors, yet it is determined by historical, physical, and developmental constraints. A constraint should not be understood as an absolute obstacle to evolution, as it may also generate new possibilities for evolutionary change. Modularity is, in this context, an important way of organizing biological information and has been recognized as a central concept in evolutionary biology bridging on developmental, genetics, morphological, biochemical, and physiological studies. In this article, we explore how modularity affects the evolution of a complex system in two mammalian lineages by analyzing correlation, variance/covariance, and residual matrices (without size variation). We use the multivariate response to selection equation to simulate the behavior of Eutheria and Metharia skulls in terms of their evolutionary flexibility and constraints. We relate these results to classical approaches based on morphological integration tests based on functional/developmental hypotheses. Eutherians (Neotropical primates) showed smaller magnitudes of integration compared with Metatheria (didelphids) and also skull modules more clearly delimited. Didelphids showed higher magnitudes of integration and their modularity is strongly influenced by within-groups size variation to a degree that evolutionary responses are basically aligned with size variation. Primates still have a good portion of the total variation based on size; however, their enhanced modularization allows a broader spectrum of responses, more similar to the selection gradients applied (enhanced flexibility). Without size variation, both groups become much more similar in terms of modularity patterns and magnitudes and, consequently, in their evolutionary flexibility. J. Exp. Zool. (Mol. Dev. Evol.) 314B:663-683, 2010. (C) 2010 Wiley-Liss, Inc.

SIZE AS A LINE OF LEAST RESISTANCE II: DIRECT SELECTION ON SIZE OR CORRELATED RESPONSE DUE TO CONSTRAINTS?

Evolutionary change in New World Monkey (NWM) skulls occurred primarily along the line of least resistance defined by size (including allometric) variation (g(max)). Although the direction of evolution was aligned with this axis, it was not clear whether this macroevolutionary pattern results from the conservation of within population genetic covariance patterns (long-term constraint) or long-term selection along a size dimension, or whether both, constraints and selection, were inextricably involved. Furthermore, G-matrix stability can also be a consequence of selection, which implies that both, constraints embodied in g(max) and evolutionary changes observed on the trait averages, would be influenced by selection Here, we describe a combination of approaches that allows one to test whether any particular instance of size evolution is a correlated by-product due to constraints (g(max)) or is due to direct selection on size and apply it to NWM lineages as a case study. The approach is based on comparing the direction and amount of evolutionary change produced by two different simulated sets of net-selection gradients (beta), a size (isometric and allometric size) and a nonsize set. Using this approach it is possible to distinguish between the two hypotheses (indirect size evolution due to constraints or direct selection on size), because although both may produce an evolutionary response aligned with g(max), the amount of change produced by random selection operating through the variance/covariance patterns (constraints hypothesis) will be much smaller than that produced by selection on size (selection hypothesis). Furthermore, the alignment of simulated evolutionary changes with g(max) when selection is not on size is not as tight as when selection is actually on size, allowing a statistical test of whether a particular observed case of evolution along the line of least resistance is the result of selection along it or not. Also, with matrix diagonalization (principal components [PC]) it is possible to calculate directly the net-selection gradient on size alone (first PC [PC1]) by dividing the amount of phenotypic difference between any two populations by the amount of variation in PC1, which allows one to benchmark whether selection was on size or not

Covariance structure in the skull of Catarrhini: a case of pattern stasis and magnitude evolution

The study of the genetic variance/covariance matrix (G-matrix) is a recent and fruitful approach in evolutionary biology, providing a window of investigating for the evolution of complex characters. Although G-matrix studies were originally conducted for microevolutionary timescales, they could be extrapolated to macroevolution as long as the G-matrix remains relatively constant, or proportional, along the period of interest. A promising approach to investigating the constancy of G-matrices is to compare their phenotypic counterparts (P-matrices) in a large group of related species; if significant similarity is found among several taxa, it is very likely that the underlying G-matrices are also equivalent. Here we study the similarity of covariance and correlation structure in a broad sample of Old World monkeys and apes (Catarrhini). We made phylogenetically structured comparisons of correlation and covariance matrices derived from 39 skull traits, ranging from between species to the superfamily level. We also compared the overall magnitude of integration between skull traits (r(2)) for all Catarrhim genera. Our results show that P-matrices were not strictly constant among catarrhines, but the amount of divergence observed among taxa was generally low. There was significant and positive correlation between the amount of divergence in correlation and covariance patterns among the 30 genera and their phylogenetic distances derived from a recently proposed phylogenetic hypothesis. Our data demonstrate that the P-matrices remained relatively similar along the evolutionary history of catarrhines, and comparisons with the G-matrix available for a New World monkey genus (Saguinus) suggests that the same holds for all anthropoids. The magnitude of integration, in contrast, varied considerably among genera, indicating that evolution of the magnitude, rather than the pattern of inter-trait correlations, might have played an important role in the diversification of the catarrhine skull. (C) 2009 Elsevier Ltd. All rights reserved.