Books by Fernando Gonzalez Candelas
La evolución, de Darwin al genoma
Hace 150 años, Charles Darwin inició una revolución científica, social e intelectual al publicar ... more Hace 150 años, Charles Darwin inició una revolución científica, social e intelectual al publicar El Origen de las Especies. Nunca una teoría científica ha tenido consecuencias tan importantes y ha ejercido una influencia tan fuerte en ámbitos tan diferentes de la actividad humana como la teoría de la evolución. Pero, lejos de ser una teoría conocida, estudiada y apreciada, la situación actual en muchos países es todavía de abierta oposición a la misma. ¿Qué hace tan peligrosa a la teoría evolutiva? ¿Tiene aún vigencia la propuesta de Darwin? ¿Cómo encajan los últimos descubrimientos de la Biología en la teoría evolutiva? ¿Necesitamos una nueva teoría para explicar la biodiversidad y las adaptaciones? Estas, y otras parecidas, son las cuestiones planteadas en este libro que pretende poner al alcance de todo el mundo los postulados i las incógnitas aún no resueltas por la teoría de la evolución
Transgénicos
El proceso de la ingesta de alimentos no se ha limitado, a lo largo de la historia de la humanida... more El proceso de la ingesta de alimentos no se ha limitado, a lo largo de la historia de la humanidad, a la mera satisfacción de una simple necesidad biológica, sino que ha ido incorporando poco a poco dimensiones religiosas, filosóficas o culturales, en forma de prescripciones y tabúes, que han hecho de la alimentación humana un campo susceptible de planteamientos y abordajes muy variados, y un asunto que puede provocar debates enconados y posturas enfrentadas.
La reciente incorporación de organismos genéticamente modificados a los alimentos que consumimos es uno de esos asuntos generadores de debates y enfrentamientos apasionados. Este libro aporta datos empíricos y argumentos científicos para que el lector se pueda hacer una idea más cabal acerca de la inocuidad o peligrosidad de los alimentos transgénicos.
Papers by Fernando Gonzalez Candelas
Comprehensive screening for naturally-occurring Hepatitis C virus resistance to direct-acting antivirals in the NS3, NS5A and NS5B genes in worldwide isolates from viral genotypes 1-6
Antimicrobial agents and chemotherapy, Jan 8, 2016
There is no comprehensive study available on the natural hepatitis C virus (HCV) polymorphism in ... more There is no comprehensive study available on the natural hepatitis C virus (HCV) polymorphism in sites associated with resistance including all viral genotypes, which may present variable susceptibilities to particular direct-acting antivirals (DAA). This study aimed to analyze the frequency, genetic barrier, and evolutionary history of naturally-occurring resistance-associated variants (RAVs) in the six main HCV genotypes. A comprehensive analysis of up to 103 RAVs was performed in 2,901, 2,216 and 1,344 HCV isolates for the NS3, NS5A and NS5B genes, respectively. We report significant inter-genotypic differences in the frequency of natural RAVs for these three HCV genes. In addition, we found a low genetic barrier for the generation of new RAVs, irrespectively of the viral genotype. Furthermore, in 1,126 HCV genomes including sequences spanning the three genes, haplotype analysis revealed a remarkably high frequency of viruses carrying more than one natural RAV to DAAs (53% of HCV...
Sequence Based Analysis reveals a polyphyletic origin of Vibrio vulnificus biotype 2
Applied and Environmental Microbiology, Nov 19, 2010
Vibrio vulnificus is a bacterial species which inhabits brackish waters from warm and tropical ec... more Vibrio vulnificus is a bacterial species which inhabits brackish waters from warm and tropical ecosystems distributed worldwide (Jones and Oliver, 2009). V. vulnificus is highly heterogeneous and has been subdivided into three biotypes (Bisharat et al., 1999; Tison et al., 1982). Biotype 1 is worldwide distributed and includes most environmental and clinical isolates of the species. This biotype causes sporadic cases of human vibriosis. Biotype 2 is less abundant but also has a worldwide distribution, and it is the only one that harbors the ...
The low levels of allozymic variability found in the Critically Endangered Borderea chouardii pro... more The low levels of allozymic variability found in the Critically Endangered Borderea chouardii prompted us to develop microsatellite markers to assess the genetic variability and population structure for the adequate conservation management of this species. A (CTT) nenriched partial genomic library was constructed. Ten polymorphic microsatellite loci were isolated from it, rendering 51 alleles in 47 individuals analysed. The allelic pattern observed for all of the loci with more than two alleles suggests that B. chouardii is tetraploid.
are most possibly xenologs. The results of the phylogenetic analyses, the distribution of xfp gen... more are most possibly xenologs. The results of the phylogenetic analyses, the distribution of xfp genes and the location of some xfp genes in plasmids are independent pieces of evidence that point to horizontal gene transfer as a major driving force in the evolution of phosphoketolases.
Borderea chouardii is a relictual and dioecious, strictly sexually reproducing, long-living geoph... more Borderea chouardii is a relictual and dioecious, strictly sexually reproducing, long-living geophyte of the Dioscoreaceae family. Previous biological and demographic studies have indicated the existence of a uniformly distributed panmictic population of this taxon at the southernmost Spanish pre-Pyrenean mountain ranges where it occurs in rather inaccessible crevices of a single limestone cliff. However, individuals of B. chouardii are spatially subdivided into two subpopulations located, respectively, on the upper and lower parts of the cliff, and vertically separated 150 m. Because of its extreme rarity, B. chouardii was the first Iberian taxon to have a specific conservation plan and has been included in several red lists under the category of critically endangered (CR). However, no previous attempts have been conducted to analyse the fine scale evolutionary mechanisms involved in its present microspatial distribution. Genetic diversity and population structure have been investigated through the analysis of neutral hypervariable markers such as simple sequence repeats (SSRs) and randomly amplified polymorphic DNAs (RAPDs) to unravel the impact of life history traits in the differentiation of the two subpopulations. Both types of molecular markers were unequivocal in distinguishing two genetically distinct groups of individuals corresponding to their spatial separation. However, SSRs detected a higher level of subpopulation differentiation ( F ST = 0.35, R ST = 0.32) than RAPDs ( F ST = 0.21). SSR data indicated significant deviation from random dispersal of genes and genotypes between the two groups, suggesting that mating occurs mainly among individuals within subpopulations, thus, favouring the divergence between the two groups. This microevolutionary differentiation scenario might have been caused by a coupled effect of past genetic drift and reproductive isolation, as a result of strong glacial age bottlenecks and inefficient dispersal system of pollen and seeds, respectively. The identification of such genetic structure in this narrow endemic prompts a modification of the management strategies of its single extant population.
Legionella pneumophila is associated to recurrent outbreaks in several Comunidad Valenciana (Spai... more Legionella pneumophila is associated to recurrent outbreaks in several Comunidad Valenciana (Spain) localities, especially in Alcoi, where social and climatic conditions seem to provide an excellent environment for bacterial growth. We have analysed the nucleotide sequences of three loci from 25 environmental isolates from Alcoi and nearby locations sampled over 3 years. The analysis of these isolates has revealed a substantial level of genetic variation, with consistent patterns of variability across loci, and comparable to that found in a large, European-wide sampling of clinical isolates. Among the tree loci studied, fliC showed the highest level of nucleotide diversity. The analysis of isolates sampled in different years revealed a clear differentiation, with samples from 2001 being significantly distinct from those obtained in 2002 and 2003. Furthermore, although linkage disequilibrium measures indicate a clonal nature for population structure in this sample, the presence of some recombination events cannot be ruled out.
[Genetic factors in severe cases of (H1N1) 2009 influenza]
Revista española de salud pública
The pandemic influenza (H1N1) 2009 raised a number of issues, of which we address the following: ... more The pandemic influenza (H1N1) 2009 raised a number of issues, of which we address the following: Why did between 25 and 30% of severe influenza cases show no obvious risk factor? We hypothesize that an element that can contribute to the answer are host genetic risk factors involved in poor disease progression. Several indications led us to this hypothesis: i) studies of familial aggregation in Iceland and Utah Mormons show some heritability of influenza mortality; ii) nearly 300 known human genes are necessary for the replication of the influenza virus, and iii) the most severe cases of influenza A (H1N1) 2009 showed a deregulation of the adaptive immune system. We are addressing this problem through a case-control design (hospitalized cases of influenza (H1N1) 2009 confirmed against outpatient cases, also confirmed for (H1N1) 2009), which will be genotyped for more than a million single nucleotide polymorphisms (SNPs) and copy number variations (CNVs).
Journal of virology, Jan 1, 2011
The molecular epidemiology of HIV-1 is constantly changing, mainly as a result of human migratory... more The molecular epidemiology of HIV-1 is constantly changing, mainly as a result of human migratory flows and the high adaptive ability of the virus. In recent years, Spain has become one of Europe's main destinations for immigrants and one of the western European countries with the highest rates of HIV-positive patients. Using a phylogeographic approach, we have analyzed the relationship between HIV-1 variants detected in immigrant and native populations of the urban area of Madrid. Our project was based on two coincidental facts. First, resistance tests were extended to naïve and newly diagnosed patients, and second, the Spanish government legislated the provision of legal status to many immigrants. This allowed us to obtain a large data set (n ؍ 2,792) from 11 Madrid hospitals of viral pol sequences from the two populations, and with this unique material, we explored the impact of immigration in the epidemiological trends of HIV-1 variants circulating in the largest Spanish city. The prevalence of infections by non-B HIV-1 variants in the studied cohort was 9%, rising to 25% among native Spanish patients. Multiple transmission events involving different lineages and subsubtypes were observed in all the subtypes and recombinant forms studied. Our results also revealed strong social clustering among the most recent immigrant groups, such as Russians and Romanians, but not in those groups who have lived in Madrid for many years. Additionally, we document for the first time the presence of CRF47_BF and CRF38_BF in Europe, and a new BG recombinant form found in Spaniards and Africans is tentatively proposed. These results suggest that the HIV-1 epidemic will evolve toward a more complex epidemiological landscape.
Genotyping of a nosocomial outbreak of pandemic influenza A/H1N1 2009
Journal of clinical virology : the official publication of the Pan American Society for Clinical Virology, Jan 1, 2011
Epidemiological surveys have revealed outbreaks of pandemic influenza A (H1N1) 2009 in several di... more Epidemiological surveys have revealed outbreaks of pandemic influenza A (H1N1) 2009 in several different contexts. Molecular characterization of the influenza virus could help to provide a more accurate description of these outbreaks.
Viruses, Jan 1, 2011
Hepatitis C virus (HCV) is a Flavivirus with a positive-sense, single-stranded RNA genome of abou... more Hepatitis C virus (HCV) is a Flavivirus with a positive-sense, single-stranded RNA genome of about 9,600 nucleotides. It is a major cause of liver disease, infecting almost 200 million people all over the world. Similarly to most RNA viruses, HCV displays very high levels of genetic diversity which have been used to differentiate six major genotypes and about 80 subtypes. Although the different genotypes and subtypes share basic biological and pathogenic features they differ in clinical outcomes, response to treatment and epidemiology. The first HCV recombinant strain, in which different genome segments derived from parentals of different genotypes, was described in St. Petersburg (Russia) in 2002. Since then, there have been only a few more than a dozen reports including descriptions of HCV recombinants at all levels: between genotypes, between subtypes of the same genotype and even between strains of the same subtype. Here, we review the literature considering the reasons underlying the difficulties for unequivocally establishing recombination in this virus along with the analytical methods necessary to do it. Finally, we analyze the potential consequences, especially in clinical practice, of HCV recombination in light of the coming new therapeutic approaches against this virus.
Emerging infectious diseases, Jan 1, 2011
Genetica, Jan 1, 2011
Limonium narbonense Miller is a fertile tetraploid species with a sporophytic self-incompatibilit... more Limonium narbonense Miller is a fertile tetraploid species with a sporophytic self-incompatibility system. This sea lavender is found in coastal salt marshes which have been under intense human pressure during the past decades resulting in significant habitat fragmentation. Eleven microsatellite loci specifically designed for this species were amplified in 135 individuals from five populations. These markers were used to investigate the polyploid nature, the levels of genetic diversity and population structure in this species. L. narbonense showed high levels of genetic diversity (A = 7.82, P = 100% H T = 0.446), consistent with its likely autotetraploid origin revealed in this study and obligate outcrossing breeding system. Inbreeding (F IS) values were low in the three southern populations (mean F IS = 0.062), and higher in the northern populations (mean F IS = 0.184). Bayesian analysis of population structure revealed that populations could be grouped into two genetic clusters, one including three southern populations and the other the two northernmost ones. Individuals from the two northernmost populations showed higher admixture of the two genetic clusters than individuals from the three southern ones. A thorough analysis of microsatellite electrophoretic patterns suggests an autotetraploid origin for L. narbonense. The genetic structure revealed in this study is attributed to a recent migration from the southern area. This result suggests a net gene flow from the south to the north, likely facilitated by migratory movements of birds visiting the temporary flooded ponds occupied by L. narbonense.
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Books by Fernando Gonzalez Candelas
La reciente incorporación de organismos genéticamente modificados a los alimentos que consumimos es uno de esos asuntos generadores de debates y enfrentamientos apasionados. Este libro aporta datos empíricos y argumentos científicos para que el lector se pueda hacer una idea más cabal acerca de la inocuidad o peligrosidad de los alimentos transgénicos.
Papers by Fernando Gonzalez Candelas