Biology subjects

Colli, G. R.

Publications and source records attributed to Colli, G. R..

3 recordsLinked to original sources

bioRxiv2025

Demographic history explains mitochondrial genome capture and mitonuclear discordance among South American collared Tropidurus lizards

Mitonuclear discordance--evolutionary discrepancies between mitochondrial and nuclear DNA phylogenies--can arise from various factors, including introgression, incomplete lineage sorting, recent or ancient demographic fluctuations, sex-biased dispersal asymmetries, among others. Understanding this phenomenon is crucial for accurately reconstructing evolutionary histories, as failing to account for discordance can lead to misinterpretations of species boundaries, phylogenetic relationships, and historical biogeographic patterns. We investigate the evolutionary drivers of mitonuclear discordance in the Tropidurus spinulosus species group, which contains nine species of lizards inhabiting open tropical and subtropical environments in South America. Using a combination of population genetic and phylogenomic approaches applied to mitochondrial and nuclear data, we identified different instances of gene flow that occurred in ancestral lineages of extant species. Our results point to a complex evolutionary history marked by prolonged isolation between species, demographic fluctuations, and potential episodes of secondary contact with genetic admixture. These conditions likely facilitated mitochondrial genome capture while diluting signals of nuclear introgression. Furthermore, we found no strong evidence supporting incomplete lineage sorting or natural selection as primary drivers of the observed mitonuclear discordance. Therefore, the unveiled patterns are most consistent with neutral demographic processes, coupled with ancient mitochondrial introgression, as the main factors underlying the mismatch between nuclear and mitochondrial phylogenies in this system. Future research could further explore the role of other demographic processes, such as asymmetric sex-biased dispersal, in shaping these complex evolutionary patterns.

genomics↗

bioRxiv2023

Severe fire regimes select for highly resilient populations in ectotherms

O_LIUnderstanding populations responses to environmental change is crucial for mitigating human-induced disturbances. C_LIO_LIHere, we test hypotheses regarding how three essential components of demographic resilience (resistance, compensation, and recovery) co-vary along the distinct life histories of three lizard species exposed to variable, prescribed fire regimes. C_LIO_LIUsing a Bayesian hierarchical framework, we estimate vital rates (survival, growth, and reproduction) with 14 years of monthly individual-level data and mark-recapture models to parameterize stochastic Integral Projection Models from five sites in Brazilian savannas, each historically subjected to different fire regimes. With these models, we investigate how weather, microclimate, and ecophysiological traits of each species influence their vital rates, emergent life history traits, and demographic resilience components in varying fire regimes. C_LIO_LIOverall, weather and microclimate are better predictors of the species vital rates, rather than their ecophysiological traits. Our findings reveal that severe fire regimes increase populations resistance, but decrease compensation or recovery abilities. Instead, populations have higher compensatory and recovery abilities at intermediate degrees of fire severity. Additionally, we identify generation time and reproductive output as predictors of resilience trends across fire regimes and climate. Our analyses demonstrate that the probability and quantity of monthly reproduction are the proximal drivers of demographic resilience across the three species. C_LIO_LIOur findings suggest that populations surpass a tipping point in severe fire regimes and achieve an alternative stable state to persist. Thus, higher heterogeneity in fire regimes can increase the reproductive aspects and resilience of different populations and avoid high-severity regimes that homogenize the environment. Despite being more resistant, species with long generation times and low reproductive output take longer to recover and cannot compensate as much as species with faster paces of life. We emphasize how reproductive constraints, such as viviparity and fixed clutch sizes, impact the ability of ectothermic populations to benefit and recover from disturbances, underscoring their relevance in conservation assessments. C_LI

ecology↗

bioRxiv2021

Using ddRAD-seq phylogeography to test for genetic effects of headwater river capture in suckermouth armored catfish (Loricariidae: Hypostomus) from the central Brazilian Shield

River capture is a geological process of potentially great importance in shaping the genetic diversity, distributions, and community composition of freshwater taxa. Using phylogeographic analyses of ddRAD-seq data from suckermouth armored catfish (Hypostomus sp. 2) populations, we tested for predicted genetic effects of headwater river capture events in central Brazil, previously supported by geological and community ecological data. We analyzed 227 ddRAD tags (3829 SNP loci) across 42 samples. Molecular results strongly supported six Hypostomus genetic clusters/lineages, with the deepest divergence [~]1.25 million years ago in the early Pleistocene between a clade from the Upper Parana and Upper Sao Francisco river basins versus all other lineages. Consistent with the Parana Capture Hypothesis, several lines of evidence supported mid-Pleistocene colonization and vicariant isolation of Hypostomus populations from an ancestral Upper Parana population, including: (1) significant phylogeographic structure, with predicted phylogenetic patterns, (2) higher Parana lineage diversity, (3) ancestral geographic locations reconstructed in the Parana basin, and (4) non-random interdrainage dispersal and vicariance events, indicating river captures primarily into the Tocantins and Upper Sao Francisco basins c. [~]220,000-145,500 years ago. Phylogeographic inference was complicated by lack of lineage monophyly across loci and lineages distributed in multiple basins, the latter of which lent support to the non-mutually exclusive Frequent Interdrainage Dispersal Hypothesis. However, species tree and demographic modeling results suggested these were artefacts of incomplete sorting of alleles in large ancestral populations over a geologically recent timeframe of divergence. Qualitative and quantitative sensitivity analyses demonstrated that our downstream genetic results were robust to effects of varying ddRAD-seq assembly parameters, which heavily influenced the number of output loci. We predict that codistributed freshwater taxa in Central Brazil may not exhibit phylogeographic patterns similar to Hypostomus sp. 2 due to complex patterns of superimposed river capture events, or if smaller ancestral population sizes have allowed more complete lineage sorting in other taxa.

evolutionary biology↗