Sibelle T Vilaça
Population genetics,
wildlife conservation, evolutionary genetics
Sea turtles
Sea turtles are fascinating, long-lived animals that have been swimming in the oceans since dinosaurs roamed the Earth. Of the seven extant species, six are of conservation concern. My research projects mainly focus in the South Atlantic populations, especially on:
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Hybridization between Loggerheads, Hawksbills, and Olive ridleys.
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Population structure, migration, and breeding stock definition.
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Microbiome characterization of different sea turtle species.
In my current postdoctoral research, I am investigating the hybridization between three sea turtle species in Brazil, the loggerhead (Caretta caretta), the olive ridley (Lepidochelys olivacea), and the hawksbill (Eretmochelys imbricata) sea turtles. This research started using few nuclear loci (Vilaça et al. 2012), evolved into the use of genomics using double digest RAD-Seq (funded by the Alexander von Humboldt Foundation, Vilaça et al. 2023), and now full genomes (funded by a Marie Curie Individual fellowship, Vilaça et al. 2021).
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The Brazilian sea turtle population is unique because of its high rates of hybridization between loggerheads and hawksbills, although four sea turtle species have been shown to hybridize in Brazil. The hybrids are mainly found in the northeastern states of Bahia and Sergipe. The other nesting and feeding populations along the coast have extremely low rates or no hybrids at all. This is a beautiful natural experiment to study and understand species hybridization under the extreme conditions of secondary contacts between long diverging genomes. The two species have been separated for 30 million years and previous studies have showed that interspecific mating is possibly driven by population decline. My goal is to describe the current impact of the hybridization in the Brazilian sea turtle population and to understand if historical processes (i.e. ancient hybridization, population bottlenecks) have played any role in these processes.
Ranavirus
Ranavirus is an emerging pathogen and can infect amphibians, fishes, reptiles. It can cause die-offs and has been associated with amphibian population declines in various parts of the world. These viruses are thought to be widespread in North America, although not much if known about its geographical distribution. As part of my postdoctoral research at Trent University, I studied ranaviruses isolated in Canada and tried to elucidate
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The genetic diversity of frog virus 3 throughout Canada using full genomes.
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Recombination patterns across different ranavirus lineages.
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Presence of ranaviruses in waterbodies (eDNA), amphibians, and turtles.
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Population Genetics
I am involved in different projects that investigate population genetics from various types of data (full genomes, RADseq, environmental DNA) to infer past and present genetic patterns like genetic diversity, population structure, changes in population size, and gene flow. Some of my current research projects are:
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Whole-genomes to inform conservation strategies for Eastern wolves in Canada.
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Global population structure, connectivity and conservation of ridley sea turtles
COLLABORATIONS
My work is highly collaborative, and I have ongoing projects with collaborators spread throughout five continents. If you are interested in sea turtles, hybridization, or see other opportunities for collaborations in population genomics, please get in touch and let's discuss possibilities!
