Biology subjects

Kunzel, S.

Publications and source records attributed to Kunzel, S..

3 recordsLinked to original sources

bioRxiv2026

The road to nowhere: geolocation-by-genotype traces large-scale yellow-browed warbler vagrancy to central Siberia

Vagrant animals - individuals found far outside their normal range - offer powerful natural experiments for understanding migratory mechanisms. The yellow-browed warbler (Phylloscopus inornatus) provides perhaps the best-yet example, typically migrating from Siberia to South/Southeast Asia yet found in increasingly large numbers in Western Europe. This represents a strikingly unresolved evolutionary puzzle: why do so many migrants consistently move in almost the complete wrong direction? A critical first step toward solving this enigma is determining where these birds come from. If vagrants came from the proximal western range edge this would imply simple disorientation, whilst a more easterly origin could imply large-scale reverse misorientation. Here, we develop a geolocation-by-genotype algorithm for low-coverage whole-genome resequencing data collected from feathers. Our method identifies spatially informative SNPs; clusters them to account for covariance in allele frequency through space; and employs a bootstrapped maximum-likelihood framework to estimate spatial origin with uncertainty. Applied to more than 80 European-caught birds, our results place their origin in central Siberia (118{degrees}E; 89-134{degrees}E [95% CI]); over 2000km east of the western range edge. These results suggest mass misorientation in a near-reverse direction, and highlight the yellow-browed warbler as an exceptional system for probing the mechanism, ontogeny and evolution of migration.

animal behavior and cognition↗

bioRxiv2024

Metabolic modeling reveals the aging-associated decline of host-microbiome metabolic interactions in mice

Aging is the predominant cause of morbidity and mortality in industrialized countries. The specific molecular mechanisms that drive aging are poorly understood, especially the contribution of the microbiota in these processes. Here, we combined multi-omics with metabolic modeling in mice to comprehensively characterize host-microbiome interactions and how they are affected by aging. Our findings reveal a complex dependency of host metabolism on microbial functions, including previously known as well as novel interactions. We observed a pronounced reduction in metabolic activity within the aging microbiome, which we attribute to reduced beneficial interactions in the microbial community and a reduction in its metabolic output. These microbial changes coincided with a corresponding downregulation of key host pathways predicted by our model to be dependent on the microbiome that are crucial for maintaining intestinal barrier function, cellular replication, and homeostasis. Our results elucidate microbiome-host interactions that potentially influence host aging processes, focusing on microbial nucleotide metabolism as a pivotal factor in aging dynamics. These pathways could serve as future targets for the development of microbiome-based therapies against aging. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=196 SRC="FIGDIR/small/587009v1_ufig1.gif" ALT="Figure 1"> View larger version (48K): org.highwire.dtl.DTLVardef@a8e7faorg.highwire.dtl.DTLVardef@115f35aorg.highwire.dtl.DTLVardef@1bbf32org.highwire.dtl.DTLVardef@1a58c7f_HPS_FORMAT_FIGEXP M_FIG C_FIG

systems biology↗

bioRxiv2019

Microbiomes from feces vs. gut in aquatic vertebrates: distinct community compositions between substrates and preservation methods

Sample type and preservation methods are likely to influence microbiome analysis results. Relatively few studies have explored the differences between feces and gut as well as ethanol-stored and frozen samples. Here, we sampled the same individuals of three aquatic vertebrates from the Qinghai-Tibetan Plateau non-invasively for feces, and subsequently for hindgut through dissection. Our study species, two fishes (Gymnocypris cf. namensis and Triplophysa sp.) and one amphibian (tadpoles of Nanorana parkeri), were all collected at the same time and site. Gut and fecal samples were stored in ethanol, and additionally, part of the gut samples were frozen, but temporarily thawed during transport as it often happens under difficult field conditions. Our results showed that both substrate (gut content vs. feces) as well as preservation method can influence the analysis of intestinal microbiomes. Frozen gut samples strongly differed from ethanol-stored samples, and especially in Nanorana most frozen samples were dominated (in relative abundance) by a set of Proteobacteria OTUs that were completely absent from the ethanol-stored samples. This blooming of contaminant bacteria occurred after less than 12 h of thawing, thus caution should be taken when constancy of cold temperatures cannot be maintained in the field for sample preservation purposes. Among ethanol-stored samples, bacterial communities from feces differed from those recovered from guts, but in part recovered similar patterns, such as a higher bacterial richness in the more herbivorous Nanorana tadpoles. Although our results argue against combining gut and fecal samples in analyses of host-specific microbiome differences, they also confirm that non-invasive sampling of feces can provide useful information of gut microbiomes in aquatic vertebrates, which may be important especially when working with endangered species.

microbiology↗