Biology subjects

Winkler, K.

Publications and source records attributed to Winkler, K..

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

Demographic responses to climatic changes during the Final Palaeolithic in Europe

The European Final Palaeolithic witnessed marked changes in almost all societal domains. Despite a rich body of evidence, our knowledge of palaeodemographic processes and regional population dynamics still needs to be improved. In this study, we present regionally differentiated estimates of absolute numbers and population densities for the Greenland Interstadial 1d-a (GI-1d-a; 14-12.7 ka BP) and the Greenland Stadial 1 (GS-1; 12.7-11.6 ka BP) for Southern, Western, Northern and Central Europe. The data were obtained by applying the Cologne Protocol, a geostatistical approach for estimating prehistoric population size and density, to a newly compiled dataset of Final Palaeolithic sites. On a large spatio-temporal scale, we observe a shift of the main areas of human occupation from the Franco-Cantabrian region, which was intensely occupied during most phases of the preceding Upper Palaeolithic, to regions north of the Alps. At smaller scales, we observe divergent regional trends in the Final Palaeolithic meta-population: during GI 1d-a, a decreasing population in southwestern Europe and an increasing population in north-eastern Central Europe. For the first time since the dispersal of anatomically modern humans into Europe, we see that Central Europe becomes the dominant demographic growth area. Subsequently, the climatic cooling of GS-1 coincides with a pronounced population decline in most parts of the study area. An apparent increase in population density occurs only in north-eastern Central Europe and north-eastern Italy. Our estimates suggest that the total population was reduced by half. Similar results, with a relationship between decreasing temperatures and decreasing populations, have already been observed for the late phase of the Gravettian, when populations were reduced to only one third of those estimated for the early phase. Yet, in contrast to the collapse of local populations during the late Gravettian, the increase in population densities in Central Europe during GS-1 indicates population movements eastwards, possibly in response to deteriorating climatic conditions, particularly in western regions during the Younger Dryas.

ecology↗

bioRxiv2019

Binding of the motor protein SecA to the bacterial protein translocation channel SecYEG in the absence of ATP

Translocation of many secretory proteins through the bacterial plasma membrane is facilitated by a complex of the SecYEG channel with the motor protein SecA. The ATP-free complex is unstable in detergent, raising the question how SecA may perform several rounds of ATP hydrolysis without being released from the membrane embedded SecYEG. Here we show that dual recognition of (i) SecYEG and (ii) vicinal acidic lipids confers an apparent nanomolar affinity. High-speed atomic force microscopy visualizes the complexes between monomeric SecA and SecYEG as being stable for tens of seconds. These long-lasting events and complementary shorter ones both give rise to single ion channel openings of equal duration. Furthermore, luminescence resonance energy transfer reveals two conformations of the SecYEG-SecA complex that differ in the protrusion depth of SecAs two-helix finger into SecYEGs aqueous channel. Such movement of the finger is in line with the power stroke mechanism of protein translocation.

biophysics↗