Biology subjects

Popovic, D.

Publications and source records attributed to Popovic, D..

3 recordsLinked to original sources

bioRxiv2018

Mechanisms of a locally adaptive shift in allocation among growth, reproduction, and herbivore resistance in Mimulus guttatus

Environmental gradients can drive adaptive evolutionary shifts in plant resource allocation among growth, reproduction, and herbivore resistance. However, few studies have attempted to connect these adaptations to underlying physiological and genetic mechanisms. Here, we evaluate potential mechanisms responsible for a coordinated locally adaptive shift between growth, reproduction, and herbivore defense in the yellow monkeyflower, Mimulus guttatus. Through manipulative laboratory experiments we found that gibberellin (GA) growth hormones may play a role in the developmental divergence between perennial and annual ecotypes of M. guttatus. Further, we detected an interaction between a locally adaptive chromosomal inversion, DIV1, and GA addition. This finding is consistent with the inversion contributing to the evolutionary divergence between inland annual and coastal perennial ecotypes by reducing GA biosynthesis/activity in perennials. Finally, we found evidence that the DIV1 inversion is partially responsible for a coordinated shift in the divergence of growth, reproduction, and herbivore resistance traits between coastal perennial and inland annual M. guttatus. The inversion has already been established to have a substantial impact on the life-history shift between long-term growth and rapid reproduction. Here, we demonstrate that the DIV1 inversion also has sizable impacts on both the total abundance and composition of phytochemical compounds involved in herbivore resistance.

evolutionary biology↗

bioRxiv2018

Human mediated dispersal of cats in the Neolithic Central Europe

Archaeological and genetic evidence suggest that all domestic cats derive from the Near Eastern wildcat (Felis silvestris lybica) and were domesticated twice, first in the Near East around 10 000 years ago and for the second time in Ancient Egypt ca. 3 500 years ago. The spread of the domesticated form in Europe occurred much later, primarily mediated by Greek and Phoenician traders and afterwards by Romans who introduced cats to Western and Central Europe around 2 000 years ago. We investigated mtDNA of Holocene Felis remains and provide evidence of an unexpectedly early presence of cats bearing the Near Eastern wildcat mtDNA haplotypes in Central Europe, being ahead of Roman Period by over 2 000 years. The appearance of the Near Eastern wildcats in Central Europe coincide with the peak of Neolithic settlement density, moreover most of those cats belonged to the same mtDNA lineages as those domesticated in the Near East. Thus, although we cannot fully exclude that the Near Eastern wildcats appeared in Central Europe as a result of introgression with European wildcat, our findings strongly support the hypothesis that the Near Eastern wildcats spread across Europe together with the first farmers, perhaps as commensal animals. We also found that cats dated to the Neolithic period belonged to different mtDNA lineages than those brought to Central Europe in Roman times, this supports the hypothesis that the gene pool of contemporary European domestic cats might have been established from two different source populations that contributed in different periods.

ecology↗

bioRxiv2016

Exploring Anti-correlated Resting State BOLD Signals Through Dynamic Functional Connectivity and Whole-brain Computational Modeling

Resting-state functional magnetic resonance imaging and diffusion weight imaging became a conventional tool to study brain connectivity in healthy and diseased individuals. However, both techniques provide indirect measures of brain connectivity leading to controversies on their interpretation. Among these controversies, interpretation of anti-correlated functional connections and global average signal is a major challenge for the field. In this paper, we used dynamic functional connectivity to calculate the probability of anti-correlations between brain regions. The brain regions forming task-positive and task-negative networks showed high anti-correlation probabilities. The fluctuations in anti-correlation probabilities were significantly correlated with those in global average signal and functional connectivity. We investigated the mechanisms behind these fluctuations using whole-brain computational modeling approach. We found that the underlying effective connectivity and intrinsic noise reflect the static spatiotemporal patterns, whereas the hemodynamic response function is the key factor defining the fluctuations in functional connectivity and anti-correlations. Furthermore, we illustrated the clinical implications of these findings on a group of bipolar disorder patients suffering a depressive relapse (BPD).

neuroscience↗