Biology subjects

DeLiberto, A. N.

Publications and source records attributed to DeLiberto, A. N..

4 recordsLinked to original sources

bioRxiv2023

Relentless Selection: The importance of within-generation selection in heterogeneous habitats

Natural selection relentlessly reshapes the genetic and phenotypic composition of populations, yet often adaptations cannot emerge due to excessive migration and gene flow. Nevertheless, in heterogeneous habitats strong selection could temporarily establish significant trait divergence among environmental patches. Here, we show that in Fundulus heteroclitus, a single generation of selection drives significant phenotypic divergence (5-15%) in organismal metabolic rate, cardiac metabolic rate and hypoxia tolerance. This divergence occurs among individuals of the same panmictic population residing in environmentally distinct microhabitats. Phenotypic divergence remains observable following long-term common-gardening and is supported by previous work documenting fine-scale, genetic divergence among microhabitat residents. We show that the magnitude of within-generation trait divergence is on the order of what is commonly observed among more isolated populations that have diverged over multiple generations. Although panmictic reproduction among microhabitat residents erodes trait divergence every generation, strong selection could potentially reestablish it in the next. In heterogeneous habitats, transient, fine-scale divergence could have a considerable impact on eco-evolutionary dynamics. Ignoring its contribution to overall trait variance could limit our ability to define meaningful, evolved divergence. SummaryNatural selection can lead to changes in organisms traits over time. Typically, these changes occur slowly over multiple generations and over large spatial scales. By studying a wild population of Atlantic killifish, we show that a single generation of natural selection can generate substantial trait variation over short distances. We observe significant differences in several physiological traits among individuals inhabiting distinct microhabitats in a patchy salt marsh environment. These differences are unlikely due to physiological acclimation and are best explained by strong, natural selection removing those individuals not suited to a particular microhabitat. Previous studies support natural selection as the most likely explanation, having shown subtle genetic differences among microhabitat residents. Remarkably, the magnitude of trait divergence is on the order of what is typically observed among populations that have diverged over multiple generations and larger spatial scales. Our results highlight the significant contribution of natural selection to trait variation in patchy environments, even over exceptionally short time and small spatial scales.

evolutionary biology↗

bioRxiv2023

Chemoproteomic profiling of 8-oxoguanosine-sensitive RNA-protein interactions

Cellular nucleic acids are subject to assault by endogenous and exogenous agents that can perturb the flow of genetic information. Oxidative stress leads to the accumulation of 8-oxoguanine (8OG) on DNA and RNA. 8OG lesions on mRNA negatively impact translation, but their effect on global RNA-protein interactions is largely unknown. Here, we apply an RNA chemical proteomics approach to investigate the effect of 8OG on RNA-protein binding. We find proteins that bind preferentially to 8OG-modified RNA, including IGF2BP1-3 and hnRNPD, and proteins that are repelled by 8OG such as RBM4. We characterize these interactions using biochemical and biophysical assays to quantify the effect of 8OG on binding and show that a single 8OG abolishes binding of RBM4 to its preferred CGG-containing substrate. Taken together, our work establishes the molecular consequences of 8OG on cellular RNA-protein binding and provides a framework for interrogating the role of RNA oxidation in biological systems.

biochemistry↗

bioRxiv2020

Measuring complex phenotypes: A flexible high-throughput design for micro-respirometry

Variation in tissue-specific metabolism between species and among individuals is thought to be adaptively important; however, understanding this evolutionary relationship requires reliably measuring this trait in many individuals. In most higher organisms, tissue specificity is important because different organs (heart, brain, liver, muscle) have unique ecologically adaptive roles. Current technology and methodology for measuring tissue-specific metabolism is costly and limited by throughput capacity and efficiency. Presented here is the design for a flexible and cost-effective high-throughput micro-respirometer (HTMR) optimized to measure small biological samples. To verify precision and accuracy, substrate specific metabolism was measured in heart ventricles isolated from a small teleost, Fundulus heteroclitus, and in yeast (Saccharomyces cerevisiae). Within the system, results were reproducible between chambers and over time with both teleost hearts and yeast. Additionally, metabolic rates and allometric scaling relationships in Fundulus agree with previously published data measured with lower-throughput equipment. This design reduces cost, but still provides an accurate measure of metabolism in small biological samples. This will allow for high-throughput measurement of tissue metabolism that can enhance understanding of the adaptive importance of complex metabolic traits.

physiology↗

bioRxiv2020

An Innovative Setup for High-Throughput Respirometry of Small Aquatic Animals

AO_SCPLOWBSTRACTC_SCPLOWMetabolic rate is often measured as a phenotype in evolutionary genetics studies because it impacts organismal fitness, is repeatable and heritable, and is responsive to numerous environmental variables. Despite a wide body of literature about metabolic rates, key questions remain unanswered: 1) why do individuals from the same population exhibit up to three fold differences in metabolic rate, 2) how does metabolic rate change during an individuals lifetime, and 3) what metabolic rate is advantageous in a specific environment? Current low throughput approaches to measure metabolic rate make it difficult to answer these and other relevant ecological and evolutionary questions that require a much larger sample size. Here we describe a scalable high-throughput intermittent flow respirometer (HIFR) design and use it to measure the metabolic rates of 20 aquatic animals simultaneously while reducing equipment costs and time by more than 50%.

physiology↗