DNA metabarcoding the diet of Podarcis lizards endemic to the Balearic Islands.

Dietary studies are essential to unravel the functioning of ecosystems and ultimately to understand biodiversity. This task, which at first may seem simple, becomes especially complex in those cases of omnivorous species with highly variable diets. In this regard, the emergence of next-generation DNA sequencing methodologies represents a powerful tool to address the problem. Here we implement a high-throughput metabarcoding strategy based on the analysis of four molecular markers aimed at sequencing both mitochondrial (animal prey) and chloroplast (diet plants) genome fragments from fecal samples of two lizard species endemic to the Balearic Archipelago (Podarcis lilfordi and P. pityusensis) obtained through non-invasive methods. The results allowed for the characterization of their diets with a high degree of taxonomic detail and have contributed a large number of new trophic records. The reported diets are based mainly on the consumption of arthropods, mollusks and plants from a diversity of taxonomic orders, as well as carrion and marine subsidies. Our analyses also reveal inter- and intra-specific differences both in terms of seasonality and geographical distribution of the sampled lizard populations. These molecular findings provide new insights into the trophic interactions of these threatened endemic lizards in their unique and isolated ecosystems.

Diet of the Insular Lizard, Podarcis lilfordi (Günther, 1874): Complementary Morphological and Molecular Approaches.

The diets of insular lizards are extremely varied, depending on the different environmental characteristics of each island population. This is particularly evident in the case of the populations of small coastal islets of the Balearic Islands, where the Balearic lizard, Podarcis lilfordi, is found. The study of trophic ecology carried out by means of traditional tools, such as morphological analysis of feces, has made it possible to detect numerous prey and nutritional elements. However, these methods are clearly insufficient, as some rare groups are not detected. It is also difficult to identify remains of marine subsidies or of foods contributed to these small islands by other predators, such as seabirds. The current study demonstrates the advantages of combining morphological diet analysis with the molecular study of individual feces samples obtained from the same populations. We obtained a greater diversity of prey groups using the combined methodologies, with each method identifying prey items that were not detected using the other method. Particularly, the study of diets at the molecular level identified plant species consumed by lizards that were, occasionally, not identified in morphological analyses. Conversely, the traditional morphological study of an equivalent number of fecal samples allowed for the identification of several prey groups that had not been detected in the molecular study. From this viewpoint, the advantages and disadvantages of each methodology are discussed.

Faecal Microbiota Divergence in Allopatric Populations of Podarcis lilfordi and P. pityusensis, Two Lizard Species Endemic to the Balearic Islands.

Gut microbial communities provide essential functions to their hosts and are known to influence both their ecology and evolution. However, our knowledge of these complex associations is still very limited in reptiles. Here we report the 16S rRNA gene faecal microbiota profiles of two lizard species endemic to the Balearic archipelago (Podarcis lilfordi and P. pityusensis), encompassing their allopatric range of distribution through a noninvasive sampling, as an alternative to previous studies that implied killing specimens of these IUCN endangered and near-threatened species, respectively. Both lizard species showed a faecal microbiome composition consistent with their omnivorous trophic ecology, with a high representation of cellulolytic bacteria taxa. We also identified species-specific core microbiota signatures and retrieved lizard species, islet ascription, and seasonality as the main factors in explaining bacterial community composition. The different Balearic Podarcis populations are characterised by harbouring a high proportion of unique bacterial taxa, thus reinforcing their view as unique and divergent evolutionary entities.

Genomic signatures of drift and selection driven by predation and human pressure in an insular lizard.

Genomic divergence was studied in 10 small insular populations of the endangered Balearic Islands lizard (Podarcis lilfordi) using double digest restriction-site associated DNA sequencing. The objectives were to establish levels of divergence among populations, investigate the impact of population size on genetic variability and to evaluate the role of different environmental factors on local adaptation. Analyses of 72,846 SNPs supported a highly differentiated genetic structure, being the populations with the lowest population size (Porros, Foradada and Esclatasang islets) the most divergent, indicative of greater genetic drift. Outlier tests identified ~ 2% of loci as candidates for selection. Genomic divergence-Enviroment Association analyses were performed using redundancy analyses based on SNPs putatively under selection, detecting predation and human pressure as the environmental variables with the greatest explanatory power. Geographical distributions of populations and environmental factors appear to be fundamental drivers of divergence. These results support the combined role of genetic drift and divergent selection in shaping the genetic structure of these endemic island lizard populations.

Acceptance and knowledge of evolutionary theory among third-year university students in Spain.

The theory of evolution is one of the greatest scientific achievements in the intellectual history of humankind, yet it is still contentious within certain social groups. Despite being as robust and evidence-based as any other notable scientific theory, some people show a strong reluctance to accept it. In this study, we used the Measure of Acceptance of the Theory of Evolution (MATE) and Knowledge of Evolution Exam (KEE) questionnaires with university students from four academic degree programs (Chemistry, English, History, and Biology) of ten universities from Spain to measure, respectively, acceptance and knowledge of evolutionary theory among third-year undergraduate students (nMATE = 978; nKEE = 981). Results show that acceptance of evolution is relatively high (87.2%), whereas knowledge of the theory is moderate (5.4 out of 10) although there are differences across degrees (Biology>Chemistry>History>English), and even among various universities (ranging from 4.71 to 5.81). Statistical analysis reveals that knowledge of evolutionary theory among Biology students is partially explained by the relative weight of evolutionary themes within the curriculum, suggesting that an increase in the number of hours dedicated to this topic could have a direct influence on students' knowledge of it. We also found that religion may have a significant-although relatively small-negative influence on evolutionary theory acceptance. The moderate knowledge of evolution in our undergraduate students, together with the potential problem of acceptance in certain groups, suggests the need for a revision of the evolutionary concepts in the teaching curricula of our students since primary school.

Relating the outcome of HCV infection and different host SNP polymorphisms in a Majorcan population coinfected with HCV-HIV and treated with pegIFN-RBV.

Hepatitis C virus (HCV) is one of the major causes of chronic hepatitis, cirrhosis, and hepatocellular carcinoma, and the development of HCV-related disease is accelerated in individuals coinfected with human immunodeficiency-1 virus (HIV). In the present study, we correlated different host single-nucleotide polymorphisms (SNPs) in the IL28B, CTLA4, LDLr, and HFE genes and mitochondrial DNA (mtDNA) haplogroups with the outcome of HCV infection and the response to pegylated-interferon plus ribavirin (pegIFN-RBV) treatment. Our study population consisted of 63 Majorcan patients coinfected with HCV and HIV and 59 anonymous unrelated controls. Whereas the population frequency of IL28B alleles was similar to that found in a North-American cohort of European descent, the frequency of the rs12979860 C allele was lower than that determined in other cohorts from Spain. The frequencies of CTLA4 and LDLr polymorphisms were comparable to those reported in other populations. Significant differences between cases and control cohorts occurred only for the H63D mutation of the HFE gene. There were no other differences in the frequencies of other polymorphisms or mtDNA haplogroups. The IL28B rs12979860 CC genotype was shown to be associated with a rapid virological response, and the spontaneous viral clearance rate for HCV was higher in patients with the CTLA4+49 G allele. There was no relationship between SNPs in the LDLr and HFE genes and mtDNA haplogroups and the response to treatment. Our results suggest that the host genetic background plays a significant role in the pegIFN-RBV response of patients coinfected with HCV and HIV.

Relating the outcome of HCV infection and different host SNP polymorphisms in a Majorcan population coinfected with HCV-HIV and treated with pegIFN-RBV

Hepatitis C virus (HCV) is one of the major causes of chronic hepatitis, cirrhosis, and hepatocellular carcinoma, and the development of HCV-related disease is accelerated in individuals coinfected with human immunodeficiency-1 virus (HIV). In the present study, we correlated different host single-nucleotide polymorphisms (SNPs) in the IL28B, CTLA4, LDLr, and HFE genes and mitochondrial DNA (mtDNA) haplogroups with the outcome of HCV infection and the response to pegylated-interferon plus ribavirin (pegIFN-RBV) treatment. Our study population consisted of 63 Majorcan patients coinfected with HCV and HIV and 59 anonymous unrelated controls. Whereas the population frequency of IL28B alleles was similar to that found in a North-American cohort of European descent, the frequency of the rs12979860 C allele was lower than that determined in other cohorts from Spain. The frequencies of CTLA4 and LDLr polymorphisms were comparable to those reported in other populations. Significant differences between cases and control cohorts occurred only for the H63D mutation of the HFE gene. There were no other differences in the frequencies of other polymorphisms or mtDNA haplogroups. The IL28B rs12979860 CC genotype was shown to be associated with a rapid virological response, and the spontaneous viral clearance rate for HCV was higher in patients with the CTLA4+49 G allele. There was no relationship between SNPs in the LDLr and HFE genes and mtDNA haplogroups and the response to treatment. Our results suggest that the host genetic background plays a significant role in the pegIFN-RBV response of patients coinfected with HCV and HIV (AU)

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