Biology subjects

Lalgudi, C.

Publications and source records attributed to Lalgudi, C..

3 recordsLinked to original sources

bioRxiv2026

Path-dependent recovery of the gut microbiome after antibiotics emerges from coupled ecological and evolutionary dynamics

Recovery of the gut microbiome after antibiotic exposure is often incomplete and variable, and the processes underlying this variation remain unclear. We performed longitudinal shotgun metagenomic sequencing of 2876 daily fecal samples from replicated humanized and conventional mouse cohorts exposed to controlled antibiotic perturbations. Metagenomic profiling recapitulated ecological trajectories previously observed by 16S sequencing, while revealing extensive strain-level dynamics, including reproducible sweeps of standing variants and de novo mutations in antibiotic target sites and regulatory loci. We also identified genetic changes whose effects depended on community composition, competitive release, and perturbation history. Cross-housing experiments revealed bidirectional strain transfer, with antibiotic-induced niche clearance enabling replacement of resident strains. In parallel, phage dynamics were heterogeneous and clustered by cage. Together, these findings show that post-antibiotic microbiome recovery is a path-dependent process shaped by selection, transmission, and phage activity, producing divergent outcomes even among closely matched communities exposed to the same perturbations.

microbiology↗

bioRxiv2026

Rapid centromere turnover and the adaptive radiation of lemurs

Centromeres represent essential chromosomal structures required for faithful chromosome segregation during cell division but are paradoxically hypermutable, leading to centromere drive and reproductive isolation in closely related species. Using long-read sequencing, we generate nearly complete genomes (2.1-2.5 Gbp) from eight lemur species and characterize the sequence, epigenetic and cytogenetic structure of 223 strepsirrhini centromeres providing an alternative primate perspective of centromere evolution. No lemur centromere consists of -satellite DNA that typifies the haplorhine lineage; instead, each species evolved its own distinct higher-order centromeric repeat sequence, varying substantially in both monomer length (ranging from 41-548 bp) and primary sequence composition (GC percentages 28.7-67.9%) including centromere cooption of telomeric repeats in brown lemurs. Most centromeres show characteristic hypomethylation dip regions (110-300 kbp) as candidates for kinetochore attachment. The centromere sequence motif shows no apparent sequence homology among lemur genera, even for species separated by less than 15 million years (Lemur and Eulemur). We estimate a >6-fold increased rate in primary centromeric motif turnover in strepsirrhines when compared to haplorhines and this occurred in conjunction with positive selection of the CENP-B protein in lemur lineages. We propose that lemur radiation and centromere diversification are linked, whereby accelerated motif turnover provides a stasipatric barrier contributing to rapid chromosomal evolution.

genomics↗

bioRxiv2026

Global trends in human birth and death seasonality suggest temperature-dependent shifts in birth months

Despite growing evidence that climate change affects public health, it remains unclear whether recent global warming has directly altered fundamental aspects of human biology at large scales. Here, we analyzed long-term trends in human birth and death seasonality, using demographic data from >100 regions worldwide. We found that both births and deaths followed remarkably persistent seasonal cycles. Births peaked through spring to fall, whereas deaths peaked in mid-winter, especially among older individuals. Across latitude, death seasonality diminished near the equator; birth seasonality remained strong across all latitudes but peaked progressively later at lower latitudes. Strikingly, birth seasonality in high-latitude regions showed synchronized phase delays in recent decades, with peak timing delayed by 2-3 months during the 1970s-2000s, converging toward lower-latitude timing and stabilizing subsequently, while death seasonality remained stable. An unbiased analysis of key socioeconomic and climatic variables revealed that temperature was the predominant predictor of birth-peak timing. Estimated conception peaks shifted away from summer amid rising heatwaves and stabilized in cooler fall/winter months, consistent with known adverse effects of heat on reproduction. Together, these results suggest that recent climate warming has reshaped the seasonal timing of human reproduction.

physiology↗