Biology subjects

Hung, C.-M.

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

3 recordsLinked to original sources

bioRxiv2025

Pleistocene demographic histories dominate contemporary genomic diversity in a continental radiation of Himalayan-Hengduan songbirds

While population genetic theory expects genetic diversity to scale predictably with population size, mounting empirical evidence has challenged this fundamental prediction. This striking inconsistency has prompted a paradigm shift in our understanding of the determinants of genetic diversity, driving increased efforts to disentangle the relative contributions of Pleistocene demography and linked selection. Here, based on systematic sampling and a unified analytical pipeline, we de novo assembled genomes for 120 songbird species breeding in the Himalayas-Hengduan Mountains (HHMs) and conducted population genomic analysis to examine the drivers of their genomic diversity. We observed a 6.5-fold variation in genome-wide heterogeneity and a 16.4-fold variation nucleotide diversity and across species. Notably, these measures of genomic diversity showed no correlation with recent population dynamics, current population size, or other contemporary factors--such as natural selection, elevational distribution, or life-history traits. Instead, historical demography strongly predicted genetic diversity, with ancestral population size during the late Pleistocene emerging as the sole correlate: larger ancestral sizes consistently coincided with higher diversity. These findings underscore the critical influence of historical demography on contemporary genetic diversity in natural populations--an insight essential for designing effective conservation strategies.

genetics↗

bioRxiv2024

Genetic purging of strongly deleterious mutations underlies black-necked crane's unusual escape from an extinction vortex

Many species are undergoing rapid demographic declines, necessitating an examination of the resulting genetic impacts. The prevailing small population paradigm posits an elevated genetic load and extinction risk. However, instances of fast recovery from severe population bottlenecks suggest alternative outcomes. To investigate this issue, we performed a population genomic analysis on the black-necked crane, analyzing 42 modern and 11 historical genomes. This study revealed substantial evidence of large-effect allele purging underlying the unexpectedly rapid population recovery following an abrupt bottleneck during the 1980s. Nevertheless, forward simulations supposing a prolonged bottleneck (e.g., five generations) predicted a reversion with negative prospects, implying that rapid population recovery served as both the cause and consequence of the species escaping from an extinction vortex. These findings shed light on a potential positive microevolutionary response to current widespread population collapses and underscore the urgency of implementing active and effective conservation strategies to reverse this trend before it becomes irreversible.

evolutionary biology↗

bioRxiv2019

Long-Term Outcomes of Pediatric Graves Disease Patients Treated with Anti-Thyroid Drugs: Experience from a Taiwan Medical Center

Graves disease (GD) is the most common cause of thyrotoxicosis in children and adolescents, accounting for 15% of all thyroid diseases during childhood. Anti-thyroid drugs (ATD) are recommended as the first-line treatment in children and adolescents. However, the remission rate is lower in children than in adults, and the optimal treatment duration and favorite factors associated with remission remain unknown. We aimed to investigate long-term outcomes of pediatric GD patients receiving ATD. We retrospectively reviewed medical charts of 300 pediatric GD subjects, who were initially treated with ATD and followed up for more than one year, from 1985 to 2017 at MacKay Childrens Hospital. The 300 patients comprised 257 (85.7%) females and 43 (14.3%) males, median age at diagnosis was 11.6 (range 2.7-17.8) years, and median follow-up period was 4.7 (range 1.1-23.9) years. Overall, 122 patients achieved the criteria for discontinuing ATD treatment, seventy-nine (39.9%) patients achieved remission, with a median follow-up period of 5.3 (range 1.5-20.1) years. Patients in the remission group were more likely to be aged < 5 years (remission vs. relapse vs. ongoing ATD; 11.4 vs. 0 vs. 2.6%, P=0.02), less likely to have a family history of thyroid disease (24.1 vs. 42.1 vs. 52.6 %, P=0.001), and had lower TRAb levels (42.8 vs. 53.6 vs. 65.1 %, P=0.02).\n\nConclusionLong-term ATD remains an effective treatment option for GD in children and adolescents. Pediatric GD patients aged < 5 years, having no family history of thyroid disease and having lower TRAb levels were more likely to achieve remission.

physiology↗