The high Andes, gene flow and a stable hybrid zone shape the genetic structure of a wide-ranging South American parrot

<p>Abstract</p> <p>Background</p> <p>While the gene flow in some organisms is strongly affected by physical barriers and geographical distance, other highly mobile species are able to overcome such constraints. In southern South America, the Andes (here up to 6,900 m) may constitute a formidable barrier to dispersal. In addition, this region was affected by cycles of intercalating arid/moist periods during the Upper/Late Pleistocene and Holocene. These factors may have been crucial in driving the phylogeographic structure of the vertebrate fauna of the region. Here we test these hypotheses in the burrowing parrot <it>Cyanoliseus patagonus </it>(Aves, Psittaciformes) across its wide distributional range in Chile and Argentina.</p> <p>Results</p> <p>Our data show a Chilean origin for this species, with a single migration event across the Andes during the Upper/Late Pleistocene, which gave rise to all extant Argentinean mitochondrial lineages. Analyses suggest a complex population structure for burrowing parrots in Argentina, which includes a hybrid zone that has remained stable for several thousand years. Within this zone, introgression by expanding haplotypes has resulted in the evolution of an intermediate phenotype. Multivariate regressions show that present day climatic variables have a strong influence on the distribution of genetic heterogeneity, accounting for almost half of the variation in the data.</p> <p>Conclusions</p> <p>Here we show how huge barriers like the Andes and the regional environmental conditions imposed constraints on the ability of a parrot species to colonise new habitats, affecting the way in which populations diverged and thus, genetic structure. When contact between divergent populations was re-established, a stable hybrid zone was formed, functioning as a channel for genetic exchange between populations.</p

Self-reported emotion regulation difficulties are associated with mood but not with the biological stress response to thin ideal exposure

BACKGROUND:Difficulties in emotion regulation have been related to psychological and physiological stress responses such as lower mood and lower parasympathetic activation (HF-HRV) under resting condition, but evidence on the potential link to the hypothalamic-pituitary-adrenal (HPA) axis functioning and to physiological stress responses during a stress task is still scarce. The aim of the study was to investigate stress responses in young women when confronted to a daily stressor such as exposure to thin ideals and to understand the role of correlates of self-reported trait-like emotion regulation difficulties (ERD). METHODS:Heart rate variability (HRV) and salivary cortisol data were collected in a sample of 273 young women aged 18-35 with and without mental disorders during a vivid imagination of thin ideals (experimental condition) or landscapes (control condition). Changes in mood states were measured on a visual analogue scale (0-100). Correlates of trait-like ERD were self-reported using the Difficulties in Emotion Regulation Scale (DERS). RESULTS:Participants with higher ERD showed a stronger decline in self-reported mood after vivid imagination of thin ideals compared to participants with lower ERD in the experimental condition but also a stronger increase of positive mood with increasing ERD in the control condition. ERD were not related to baseline HF-HRV or baseline salivary cortisol levels nor to any physiological response during and after the imagination of thin ideals. DISCUSSION AND CONCLUSION:The results corroborate the role of ERD regarding the immediate psychological impact of daily stressors. Exposition to daily stressors in the laboratory results in discrepant psychological and physiological reactivity. Future studies should investigate under what conditions the complex interrelations between immediate and long-term ERD and biological activation are amenable to assessment in a laboratory setting. The additive effects of multiple exposition to stressors, such as thin ideals in daily life, also need to be addressed

Isolation of tetranucleotide microsatellite loci in the burrowing parrot (Cyanoliseus patagonus)

Klauke N, Masello J, Quillfeldt P, Segelbacher G. Isolation of tetranucleotide microsatellite loci in the burrowing parrot (Cyanoliseus patagonus). Journal of Ornithology. 2009;150(4):921-924.We isolated seven novel polymorphic microsatellite DNA loci from the burrowing parrot (Cyanoliseus patagonus) and optimised them for future studies of population differentiation and genetic variation. The loci were screened for polymorphism using 38 samples from wild individuals from three neighbouring colonies in Argentina. The primers amplified highly variable loci characterised by 3–10 alleles per locus and their observed and expected heterozygosities ranged from 0.15 to 0.78 and 0.15 to 0.81, respectively. When we analysed 52 samples across Argentina and Chile, we found strong genetic differentiation between the Chilean and the Argentinean subspecies as well as significant differentiation between two geographically separated subspecies within Argentina. Our results indicate the suitability of these microsatellites for investigating further questions regarding the population genetics in this species

Limited Dispersal and Significant Fine - Scale Genetic Structure in a Tropical Montane Parrot Species

<div><p>Tropical montane ecosystems are biodiversity hotspots harbouring many endemics that are confined to specific habitat types within narrow altitudinal ranges. While deforestation put these ecosystems under threat, we still lack knowledge about how heterogeneous environments like the montane tropics promote population connectivity and persistence. We investigated the fine-scale genetic structure of the two largest subpopulations of the endangered El Oro parakeet (<i>Pyrrhura orcesi</i>) endemic to the Ecuadorian Andes. Specifically, we assessed the genetic divergence between three sites separated by small geographic distances but characterized by a heterogeneous habitat structure. Although geographical distances between sites are small (3–17 km), we found genetic differentiation between all sites. Even though dispersal capacity is generally high in parrots, our findings indicate that dispersal is limited even on this small geographic scale. Individual genotype assignment revealed similar genetic divergence across a valley (~ 3 km distance) compared to a continuous mountain range (~ 13 km distance). Our findings suggest that geographic barriers promote genetic divergence even on small spatial scales in this endangered endemic species. These results may have important implications for many other threatened and endemic species, particularly given the upslope shift of species predicted from climate change.</p></div

Map of the global distribution range of El Oro parakeets and the study sites.

<p>(a) The global distribution range specified by the yellow area is based on recent population monitoring data of Cesar Garzon (marked elevational range: 800–1400 m). The dashed square specifies the study area. In the right-hand corner, the spatial location of the study area within Ecuador is shown. (b) Sampling locations at the southern (orange circles) and northern part (blue circles) of Buenaventura reserve and Cerro Azul (green circle). Dashed line in (b) specifies the borders of Buenaventura reserve. The Buenaventura valley separates BV_South and BV_North and lies outside the distribution range of parakeets (yellow area). Forested areas are highlighted in light green and inferred from geo-referenced satellite images (RapidEye, Blackbridge, Germany) taken in 2010 and 2013. Contour lines are given in 500 m steps.</p

Dispersal rates between the sampling locations inferred by BayesAss.

<p>Dispersal rates between the sampling locations inferred by BayesAss.</p

Significance levels for Wilcoxon test and Sign test for a recent bottleneck event measured as heterozygosity excess and assuming different mutation models.

<p>Significance levels for Wilcoxon test and Sign test for a recent bottleneck event measured as heterozygosity excess and assuming different mutation models.</p

Genetic structure within the three study sites as inferred from the Structure analyses.

<p>Study sites comprise the southern area of Buenaventura (BV_South), the northern area of Buenaventura (BV_North) and Cerro Azul (CA). Each bar corresponds to an individual´s probability of belonging to a specific genetic cluster. Distinct clusters are assigned to different colours. Displayed are the results of Bayesian clustering analysis with prior information on sampling location for several numbers of K clusters. Presented are the results obtained a.) for the complete data set (n = 249) and b.) for the reduced data set (n = 65). The highest probability of clusters according to Evanno´s delta K was K = 2 for both data sets and K = 4 and K = 11 for the reduced and complete data set, respectively, using highest mean posterior likelihood.</p

Pairwise genetic differentiation measured as Jost´s D and G_ST and bias-corrected for small sample sizes (est).

<p>Pairwise genetic differentiation measured as Jost´s D and G_ST and bias-corrected for small sample sizes (est).</p

Genetic diversity calculated as mean (± SE) for each sampling location and for the whole data set (N = sample size).

<p>Genetic diversity calculated as mean (± SE) for each sampling location and for the whole data set (N = sample size).</p