Publications by authors named "Alfredo Ascanio"

Article Synopsis
  • The text discusses gene flow and isolation as key processes that influence genetic diversity, emphasizing the importance of understanding their geographic and temporal variations for promoting diversification.
  • In the context of Desert Spiny Lizards and Baja Spiny Lizards, the study investigates geographic barriers such as the Colorado River and Western Continental Divide to determine their role in genetic differentiation.
  • Results indicate that while the Western Continental Divide acts as a strong barrier to gene flow, the Colorado River is less restrictive; the study underscores the utility of genomic data and multi-source analyses to better understand the complex nature of lineage divergence.
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Article Synopsis
  • Hybridization enables genetic mixing between different species, influenced by both chance and natural selection.
  • In a study of Caribbean anole hybrids, researchers found that these hybrids mainly display characteristics of one species (A. pulchellus) but carry mitochondrial DNA from another (A. krugi), showing evidence of multiple hybridization events.
  • Genomic analysis revealed that while hybrids predominantly inherit genes from A. pulchellus (80%-90% of their genetic makeup), certain A. krugi genes connected to development and immune function are more likely to introgress due to selective advantages, suggesting an evolutionary preference for compatible mitochondrial and nuclear genes.
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The chemical composition and stoichiometry of vertebrate bodies changes greatly during ontogeny as phosphorus-rich bones form, but we know little about the variation among species during early development. Such variation is important because element ratios in animal bodies influence which element limits growth and how animals contribute to nutrient cycling. We quantified ontogenetic variation from embryos through 2-3 months of age in 10 species of fish in six different families, ranging in adult size from 73 to 720 mm in length.

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Article Synopsis
  • - The study introduces the genome of the desert horned lizard (Phrynosoma platyrhinos), revealing insights into its chromosomal structure compared to 12 other reptile genomes, including lizards, snakes, turtles, and a bird.
  • - The genome assembly, which spans nearly 1.9 billion base pairs and consists of both macrochromosomes and microchromosomes, reveals distinct differences in gene content, density, and distribution of repeat elements.
  • - The findings illustrate significant evolutionary changes in reptile karyotypes, highlighting frequent chromosomal rearrangements and functional distinctions between microchromosomes and macrochromosomes.
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This dataset contains 2850 photographs of the seafloor in coral communities from Venezuela that were taken during 2017 and 2018. We used a hierarchical experimental design with four random factors representing four different spatial scales: (1) region (hundreds of kilometers), (2) localities (tens of kilometers), (2) reef sites (hundreds of meters) and (3) transects (a couple meters) across the Venezuelan coast. At each site, four 30-m transects were deployed parallel to the coastline, and 15 pictures were taken every other meter at each transect, containing an area of at least 80 × 90cm with enough resolution to identify benthic groups.

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Estimating variability across spatial scales has been a major issue in ecology because the description of patterns in space is extremely valuable to propose specific hypotheses to unveil key processes behind these patterns. This paper aims to estimate the variability of the coral assemblage structure at different spatial scales in order to determine which scales explain the largest variability on β-diversity. For this, a fully-nested design including a series of hierarchical-random factors encompassing three spatial scales: (1) regions, (2) localities and (3) reefs sites across the Venezuelan territory.

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The characteristics of coral reef sampling and monitoring are highly variable, with numbers of units and sampling effort varying from one study to another. Numerous works have been carried out to determine an appropriate effect size through statistical power; however, these were always from a univariate perspective. In this work, we used the pseudo multivariate dissimilarity-based standard error (MultSE) approach to assess the precision of sampling scleractinian coral assemblages in reefs of Venezuela between 2017 and 2018 when using different combinations of number of transects, quadrats and points.

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Coral disease research encompasses five decades of undeniable progress. Since the first descriptions of anomalous signs, we have come to understand multiple processes and environmental drivers that interact with coral pathologies. In order to gain a better insight into the knowledge we already have, we explored how key topics in coral disease research have been related to each other using network analysis.

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Synopsis of recent research by authors named "Alfredo Ascanio"

  • - Alfredo Ascanio's recent research focuses on genetic diversity and evolutionary processes across various species, with notable studies on gene flow and isolation in desert lizards, and hybridization in Caribbean anoles, indicating the importance of both environmental factors and selective advantages in shaping genetic patterns.
  • - His work also includes an investigation of ontogenetic variation in the ecological stoichiometry of fish species, highlighting how body composition changes during development and its implications for nutrient cycling in aquatic ecosystems.
  • - Ascanio has contributed to the understanding of coral reef ecosystems through studies that explore spatial scales in coral diversity, sampling design improvements for coral monitoring, and a comprehensive meta-analysis of coral disease research, emphasizing the interconnectedness of ecological and evolutionary dynamics in marine environments.