Biology subjects

Hung, T.-C.

Publications and source records attributed to Hung, T.-C..

5 recordsLinked to original sources

bioRxiv2026

Quantifying the evolutionary potential for Delta Smelt persistence in a warming habitat

Long-term persistence of managed species will depend, in part, on whether the species harbors the physiological or genetic potential to adjust to warming temperatures, and whether relevant genetic variation is modified by management practices. The critically endangered Delta Smelt (Hypomesus transpacificus) is intensively managed, but little is known about the presence of genetic variation for resistance to elevated temperature, which will be important to maintain for their persistence in a rapidly warming future. Using a pedigree and whole genome sequencing data, we characterized the genetic variation and genomic architecture for CTMax (as a metric of upper thermal tolerance) across control and elevated rearing temperatures, alongside covarying traits (body size, degree of hatchery ancestry). Warmer rearing temperatures increased CTMax through acclimation but also resulted in reduced additive genetic variation for the trait, which could constrain adaptation under thermal stress. We found that larger fish had reduced CTMax, although this effect was diminished at elevated temperatures. We observed modest heritability for CTMax at rearing temperatures of 15{degrees}C and 18{degrees}C (0.26 and 0.16, respectively), but only a limited number of loci were identified that had consistent effects on CTMax across rearing temperatures. Instead, the genomic basis of thermal tolerance was highly dependent on rearing temperature (many loci detected with a GxE effect). The influence of domestication selection was indicated by changes in allele frequency, and divergence in upper thermal tolerance and plasticity, between low and high hatchery ancestry groups. Minimal overlap between loci associated with domestication and CTMax suggests that these traits possess separate genetic underpinnings. Knowledge of genetic variation supporting ecologically relevant physiological variation may be useful for refuge management and may inform supplementation in an ever-warming environment.

evolutionary biology↗

bioRxiv2025

Human-specific tandem repeat in CACNA1C modulates responses to neuronal stimulation

The recent development of long-read sequencing has made it possible to catalog variable number tandem repeats (VNTRs) in the human genome. However, little is known about their functional consequences. Here, we characterized the effect of TRACT, a VNTR that is unique to humans and that has sequence variants linked to risk for bipolar disorder and schizophrenia. By adding or removing this VNTR in both mouse models and human neural organoids, we find that TRACT, which is intronic to the L-type voltage-gated calcium channel gene CACNA1C, increases intracellular calcium after neuronal stimulation and leads to widespread changes in activity-dependent transcription programs in neurons. TRACT-dependent changes are enriched for genes associated with synapse formation and plasticity, and partially recapitulate evolutionary changes in activity-dependent transcription between species. These findings demonstrate that a single, human-specific, non-coding element can strongly affect the neuronal response to stimulation, and motivate the study of VNTRs as a genetic source of phenotypic variation in both evolution and disease.

genetics↗

bioRxiv2025

Highly and lowly domesticated endangered fish from a conservation hatchery diverge in their thermal physiology, transcriptome, and methylome

Conservation hatcheries aim to produce fish for supplementation of wild populations, but hatchery environments may drive phenotypic divergence from wild fish. These diverged traits may have reduced fitness in the wild, which could compromise wild population sustainability and evolutionary potential, such as in response to climate change. Delta smelt are a critically endangered fish species that are safeguarded against extinction with a hatchery refuge population. We investigated whether elevated rearing temperature through larval development adjusted upper thermal tolerance limits (acclimation) in Delta smelt, whether upper thermal tolerance and plasticity (acclimation ability) differed between fish with old or recent hatchery ancestry (high or low domestication index; DI), and temperature and DI effects on liver transcriptome and methylome patterns. We observed that elevated rearing temperatures induced higher thermal tolerance (acclimation). Individuals with higher DI also had higher upper thermal tolerances, but high DI families had reduced thermal plasticity between rearing temperatures. This is consistent with domestication causing heritable elevation of upper thermal tolerance but at the cost of reduced thermal plasticity. High and low DI fish were differentiated in both genetic variation and methylome variation, suggesting the influence of both during domestication. But methylome differences distinguishing high and low DI fish did not overlap with temperature-induced methylome changes, and do not appear to be stably inherited in the hatchery. We conclude that domestication selection has altered thermal physiology within the refuge hatchery despite careful genetic management, underpinned by shifts in the transcriptome and methylome. These changes could affect Delta smelt fitness upon reintroduction to habitats that continue to warm, and show that physiological traits can diverge even within carefully genetically managed hatchery populations.

evolutionary biology↗

bioRxiv2023

Boundary stacking interactions enable cross-TAD enhancer-promoter communication during limb development

While long-range enhancers and their target promoters are frequently contained within a TAD, many developmentally important genes have their promoter and enhancers within different TADs. Hypotheses about molecular mechanisms enabling such cross-TAD interactions remain to be assessed. To test these hypotheses, we use Optical Reconstruction of Chromatin Architecture (ORCA) to characterize the conformations of the Pitx1 locus on thousands of single chromosomes in developing mouse limbs. Our data supports a model in which neighboring boundaries are stacked with each other as a result of loop-extrusion, bringing boundary-proximal cis-elements into contact. This stacking interaction also explains the appearance of architectural stripes in the population average maps (e.g. Hi-C data). Through molecular dynamics simulations, we further propose that increasing boundary strengths facilitates the formation of the stacked boundary conformation, counter-intuitively facilitating border bypass. This work provides a revised view of the TAD borders function, both facilitating as well as preventing cis-regulatory interactions, and introduces a framework to distinguish border-crossing from border-respecting enhancer-promoter pairs.

developmental biology↗

bioRxiv2022

The high diversity of Scedosporium and Lomentospora species and their prevalence in human-disturbed areas in Taiwan

Scedosporium and Lomentospora are important opportunistic pathogens causing localized or disseminated infection in humans. Understanding their environmental distribution is critical for public hygiene and clinical management. We carried out the first environmental survey in urbanized and natural regions in Taiwan. Overall, Scedosporium and Lomentospora species were recovered in 130 out of 271 soil samples (47.9%) across Taiwan. We morphologically and molecularly identified five Scedosporium species and one Lomentospora species. All four major clinical relevant species were isolated with high frequency, i.e. S. apiospermum (42.5%), S. boydii (27.5%), L. prolificans (15.0%), and S. aurantiacum (8.8%); two clinically minor species, S. dehoogii (5.6%) and S. haikouense (0.6%), had moderate incidence. These fungal species have high incidence in urban (48%) and hospital (67.4%) soil samples, and have limited distribution in samples from natural regions (5%). Multivariate analysis of the fungal composition revealed strong evidence of the preferential distribution of these fungi in urban and hospital regions compared to natural sites. In addition, strong evidence suggested that the distribution and abundance of these fungal species are highly heterogeneous in the environment; samples in vicinity often yield varied fungal communities. Our results indicated that these fungal species are prevalent in soil in Taiwan and their occurrences are associated with human activities. Hygiene sensitive places such as hospitals should be particularly aware of the high frequency of the clinical relevant species.

microbiology↗