Juliana A Vianna

Pontifical Catholic University of Chile | UC · Departamento de Ecosistemas y Medio Ambiente

The relative importance of genetic drift and local adaptation in facilitating speciation remains unclear. This is particularly true for seabirds, who can disperse over large geographic distances, providing opportunities for intermittent gene flow among distant colonies that span the temperature and salinity gradients of the oceans. Here, we delve i...

The major histocompatibility complex (MHC) is a genetic region in jawed vertebrates that contains key genes involved in the immune response. Associations between the MHC and avian malaria infections in wild birds have been observed and mainly explored in the Northern Hemisphere, while a general lack of information remains in the Southern Hemisphere...

The increased availability of quality genomic data has greatly improved the scope and resolution of our understanding of the recent evolutionary history of wild species adapted to extreme environments and their susceptibility to anthropogenic impacts. The guanaco (Lama guanicoe), the largest wild ungulate in South America, is a good example. The gu...

The genetic identification of evolutionary significant units and information on their connectivity can be used to design effective management and conservation plans for species of concern. Despite having high dispersal capacity, several seabird species show population structure due to both abiotic and biotic barriers to gene flow. The Kelp Gull is...

Suspected cases of Highly Pathogenic Avian Influenza (H5N1) were detected in Adelie penguins and Antarctic shags at the southernmost latitude so far in Antarctica, at two breeding sites out of 13 visited, using highly specific PCR assay. These first records mark the progression of the H5N1 panzootic into Antarctica.

Oceanic seabirds have suffered population declines and extirpations due to human disturbance and still face multiple threats. Here, we assessed the potential genetic vulnerability of the red-tailed tropicbird, Phaethon rubricauda, a seabird species threatened by human disturbance and listed as ‘least concern’ by the IUCN. Using Single Nucleotide Po...

The divergence between the Andean fox (Lycalopex culpaeus) and the South American gray fox (L. griseus) represents a recent speciation event in South America. These taxa are partially sympatric and share biological, morphological, and ecological traits. Previous studies failed to recover reciprocal monophyly, suggesting the occurrence of introgress...

Comparative whole-genome analyses hold great power to illuminate commonalities and differences in the evolution of related species that share similar ecologies. The mustelid subfamily Lutrinae includes 13 currently recognized extant species of otters,1, 2, 3, 4, 5 a semiaquatic group whose evolutionary history is incompletely understood. We assembl...

Two divergent genetic lineages have been described for the endangered green turtle in the Pacific Ocean, occurring sympatrically in some foraging grounds. Chile has seven known green turtle foraging grounds, hosting mainly juveniles of different lineages. Unfortunately, anthropic factors have led to the decline or disappearance of most foraging agg...

Two divergent genetic lineages have been described for the endangered green turtle in the Pacific Ocean, occurring sympatrically in some foraging grounds. Chile has seven known green turtle foraging grounds, hosting mainly juveniles of different lineages. Unfortunately, anthropic factors have led to the decline or disappearance of most foraging agg...

Chile is a large country with a marked range of climate conditions that make it an ideal scenario for the study of vector-borne parasites; however, knowledge about their distribution is limited to a few confined areas of this country. The presence of Hepatozoon spp., piroplasmids, Leishmania spp. and filarioids was investigated through molecular an...

Although mitochondrial DNA has been widely used in phylogeography, evidence has emerged that factors such as climate, food availability, and environmental pressures that produce high levels of stress can exert a strong influence on mitochondrial genomes, to the point of promoting the persistence of certain genotypes in order to compensate for the m...

Penguins (Sphenisciformes) are an iconic order of flightless, diving seabirds distributed across a large latitudinal range in the Southern Hemisphere. The extensive area over which penguins are endemic is likely to have fostered variation in pathogen pressure, which in turn will have imposed differential selective pressures on the penguin immune sy...

The spatial and trophic ecology of the culpeo fox (Lycalopex culpaeus) was studied in the Salar de Punta Negra basin and the Llullaillaco National Park, in the high Andes of the Region of Antofagasta in northern Chile. The objectives of this study were to understand the feeding ecology, habitat use, and home range and activity pattern of culpeo fox...

The spatial and trophic ecology of the culpeo fox (Lycalopex culpaeus) was studied in the Salar de Punta Negra basin and the Llullaillaco National Park, in the high Andes of the Region of Antofagasta in northern Chile. The objectives of this study were to understand the feeding ecology, habitat use, and home range and activity pattern of culpeo fox...

A fishy tale of long and short life span Fish have wide variations in life span even within closely related species. One such example are the rockfish species found along North Pacific coasts, which have life spans ranging from 11 to more than 200 years. Kolora et al . sequenced and performed a genomic analysis of 88 rockfish species, including lon...

Aim Many pinniped species have experienced drastic demographic changes due to their interaction with humans. Most studies, however, have failed to detect recent bottlenecks in otariids from genetic data. The South American Sea Lion Otaria flavescens have a long history of population changes associated with interglacial expansion and hunting to almo...

Aim Delimiting recently diverged species is challenging. During speciation, genetic differentiation may be distributed unevenly across the genome, as different genomic regions can be subject to different selective pressures and evolutionary histories. Reliance on limited numbers of genetic markers that may be underpowered can make species delimitat...

The major histocompatibility complex (MHC) is a highly polymorphic gene group that mediates the vertebrate immune response through antigen recognition and presentation. The ability to face an emerging infectious disease is greatly attributable to the genetic diversity of the MHC genes due to its main role in the adaptive immune response of vertebra...

Marine species may exhibit genetic structure accompanied by phenotypic differentiation related to adaptation despite their high mobility. Two shape-based morphotypes have been identified for the green turtle (Chelonia mydas) in the Pacific Ocean: the south-central/western or yellow turtle and north-central/ eastern or black turtle. The genetic diff...

Marine species may exhibit genetic structure accompanied by phenotypic differentiation related to adaptation despite their high mobility. Two shape-based morphotypes have been identified for the green turtle (Chelonia mydas) in the Pacific Ocean: the south-central/western or yellow turtle and north-central/eastern or black turtle. The genetic diffe...

Anaplasma platys and Ehrlichia canis are members of the Anaplasmataceae family that cause disease in dogs and are mainly transmitted by Rhipicephalus sanguineus species group ticks. We performed a cross-sectional study on these pathogens across six bioclimatic regions of Chile, including 719 free-ranging rural dogs, 132 Andean foxes (Lycalopex culp...

Animals constantly test the borders of their own ecological niche and tend to expand their range, which is now additionally challenged by global climate change. Following human exploitation throughout the Southern Ocean in the 19th and the beginning of the 20th century, numbers of King Penguin breeding pairs have increased and former breeding sites...

The specialist versus generalist strategies of hemoparasites in relation to their avian host, as well as environmental factors, can influence their prevalence, diversity and distribution. In this paper we investigated the influence of avian host species, as well as the environmental and geographical factors, on the strategies of Haemoproteus and Pl...

Blood samples of 626 rural dogs, 139 Andean foxes (Lycalopex culpaeus), and 83 South American grey foxes (L. griseus) from six bioregions of Chile spanning 3,000 km. were screened for Mycoplasma DNA by conventional PCR and sequencing. Risk factors of infection were inferred using GLMMs and genetic structure by network analyses. Overall, M. haemocan...

Patterns of genetic structure in highly mobile marine vertebrates may be accompanied by phenotypic variation. Most studies in marine turtles focused on population genetic structure have been performed at rookeries. We studied whether genetic and morphological variation of the endangered green turtle (Chelonia mydas) is consistent geographically, fo...

Climate changes during the late Pleistocene influenced the demography and distribution of species in Patagonia. During the last glacial maximum (LGM), ice sheets covered a great extent of the temperate rainforest in the western Patagonian Andes. The persistence of forest species in refugia during the LGM has been debated for many vertebrates, but r...

Penguins are the only extant family of flightless diving birds. They currently comprise at least 18 species, distributed from polar to tropical environments in the Southern Hemisphere. The history of their diversification and adaptation to these diverse environments remains controversial. We used 22 new genomes from 18 penguin species to reconstruc...

Aim The conservation of biodiversity is hampered by data deficiencies, with many new species and subspecies awaiting description or reclassification. Population genomics and ecological niche modelling offer complementary new tools for uncovering functional units of phylogenetic diversity. We hypothesize that phylogenetically delineated lineages of...

Latitudinal gradients are well-suited systems that may be helpful explaining distribution of haemosporidian parasites and host susceptibility. We studied the prevalence, diversity and drivers of haemosporidian parasites (Leucocytozoon, Plasmodium and Haemoproteus) along a latitudinal gradient (30°–56° S), that encompass the total distribution (~3,0...

A molecular genetic protocol for distinguishing pure and hybrid South American camelids was developed to provide strong, quantifiable, and unbiased species identification. We detail the application of the approach in the context of a criminal case in the Andes Mountains of central Chile where the defendants were alleged to have illegally hunted thr...

Abstract Population connectivity is driven by individual dispersal potential and modulated by natal philopatry. In seabirds, high vagility facilitates dispersal yet philopatry is also common, with foraging area overlap often correlated with population connectivity. We assess the interplay between these processes by studying past and current connect...

Over evolutionary time, pathogen challenge shapes the immune phenotype of the host to better respond to an incipient threat. The extent and direction of this selection pressure depends on the local pathogen composition, which is in turn determined by biotic and abiotic features of the environment. However, little is known about adaptation to local...

Climate shifts are key drivers of ecosystem change. Despite the critical importance of Antarctica and the Southern Ocean for global climate, the extent of climate-driven ecological change in this region remains controversial. In particular, the biological effects of changing sea ice conditions are poorly understood. We hypothesize that rapid postgl...

The study of systematics in wide-ranging seabirds can be challenging due to the vast geographic scales involved, as well as the possible discordance between molecular, morphological and behavioral data. In the Southern Ocean, macaroni penguins (Eudyptes chrysolophus) are distributed over a circumpolar range including populations in Antarctic and su...

The upwelling hypothesis has been proposed to explain reduced or lack of population structure in seabird species specialized in food resources available at cold-water upwellings. However, population genetic structure may be challenging to detect in species with large population sizes, since variation in allele frequencies are more robust under gene...

Microsatellites analyzed for Humboldt penguins: Range of fragment size in base pairs (bp) (S), annealing temperature (AT), total number of alleles (Na), expected (He) and observed heterozygosity (Ho), Chi-Square from Hardy-Weinberg Equilibrium (HWE), probability from HWE (p). (DOCX)

Hardy-Weinberg test to each locus from colonies of Humboldt penguin at Pacific coast. (DOCX)

Discriminant function DAPC from Humboldt penguin, based on 10 microsatellites. (DOCX)

Pairwise RST based on genotypes of 10 microsatellite loci (below) and Nm based on RST (above) for Humboldt penguins. Significant values (P<0.05) are in bold. Population reference: CHI (Chiloé), PUP (Pupuya), ALG (Algarrobo), CAC (Cachagua), TIL (Tilgo), PAJ (Pajaros), CHO (Choros), CHA (Chañaral), GRA (Isla Grande), AZU (Pan de Azucar), PSJ (Punta...

Sex ratio of Humboldt penguin for each colony at Pacific coast. Population reference: CHI (Chiloé), PUP (Pupuya), ALG (Algarrobo), CAC (Cachagua), TIL (Tilgo), PAJ (Pajaros), CHO (Choros), CHA (Chañaral), GRA (Isla Grande), AZU (Pan de Azucar), PSJ (Punta San Juan). (DOCX)

Frequency of migrant male and female from first generation among colonies, and in gray proportion of philopatric rate. CAC (Cachagua), TIL (Tilgo), PAJ (Pajaros), CHO (Choros), CHA (Chañaral), GRA (Isla Grande), AZU (Pan de Azucar), PSJ (Punta San Juan). (DOCX)

Skyline plot of Humboldt penguin from Pacific coast to D-loop mtDNA and RAG1 nDNA. (DOCX)

Bottleneck summary results from SMM, IAM and TPM mutation model through Wilcoxon test, mean heterozygosity (He); mean k. Population reference: CHI (Chiloé), PUP (Pupuya), ALG (Algarrobo), CAC (Cachagua), TIL (Tilgo), PAJ (Pajaros), CHO (Choros), CHA (Chañaral), GRA (Isla Grande), AZU (Pan de Azucar), PSJ (Punta San Juan). (DOCX)

Results delta K´Evano implemented by Haverst web. (DOCX)

MicrossatelitesHumboldtPenguindataset- complete microsatellites data set for Humboldt penguin. (TXT)

Pairwise ϕST based on mtDNA (below) and RAG1 (above) for Humboldt penguins. Significant values (P<0.05) are in bold. Population reference: CHI (Chiloé), PUP (Pupuya), ALG (Algarrobo), CAC (Cachagua), TIL (Tilgo), PAJ (Pajaros), CHO (Choros), CHA (Chañaral), GRA (Isla Grande), AZU (Pan de Azucar), PSJ (Punta San Juan). (DOCX)

Number of migrants of Humboldt penguin estimated based on RST from 9 microsatellites. Population reference: CHI (Chiloé), PUP (Pupuya), ALG (Algarrobo), CAC (Cachagua), TIL (Tilgo), PAJ (Pajaros), CHO (Choros), CHA (Chañaral), GRA (Isla Grande), AZU (Pan de Azucar), PSJ (Punta San Juan). (DOCX)

Bayesian STRUCTURE of the Humboldt penguin, delta K = 2 and K = 3, using admixture and no-admixture model. (DOCX)

Background Parasite prevalence and diversity are determined by the distribution of hosts and vectors and by the interplay among a suite of environmental factors. Distributions of parasite lineages vary based on host susceptibility and geographical barriers. Hemoparasites of the genera Haemoproteus and Plasmodium have wide distributions, and high pr...

Since at least the middle-Miocene, the Antarctic Polar Front (APF) and the Subtropical Front (STF) appear to have been the main drivers of diversification of marine biota in the Southern Ocean. However, highly migratory marine birds and mammals challenge this paradigm and the importance of oceanographic barriers. Eudyptes penguins range from the An...

Since at least the middle-Miocene, the Antarctic Polar Front (APF) and the Subtropical Front (STF) appear to have been the main drivers of diversification of marine biota in the Southern Ocean. However, highly migratory marine birds and mammals challenge this paradigm and the importance of oceanographic barriers. Eudyptes penguins range from the An...

Introduction: the family Anaplasmataceae is composed of obligatory intracellular organisms that parasitize different types of host cells, including the genus Ehrlichia and Anaplasma. In Chile, there is limited information about their presence in dogs, and no information exists regarding free-livings wild canids. Objects: our aim was to investigate...

Abstract Context. Biological invasions have caused dramatic changes in native biodiversity and ecosystem function. Studies of genetic variation and evolutionary changes are useful for understanding population dynamics during biological invasions, and shed light on management, prevention and restoration strategies. Aims. This study aimed to invest...

Correction to: BMC Evolutionary Biology (2018) 18:90 https://doi.org/10.1186/s12862-018-1207-0 .

Penguins are reliable sentinels for environmental assessments of mercury (Hg) due to their longevity, abundance, high trophic level, and relatively small foraging areas. We analyzed Hg concentrations from blood and feathers of adult Humboldt penguins (Spheniscus humboldti) and feathers of chinstrap penguins (Pygoscelis antarcticus) from different r...

Background: Historical factors, demography, reproduction and dispersal are crucial in determining the genetic structure of seabirds. In the Antarctic marine environment, penguins are a major component of the avian biomass, dominant predators and important bioindicators of ecological change. Populations of chinstrap penguins have decreased in nearl...