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Projeto de investigação
PROGRAMA DOUTORAL EM BIOLOGIA E ECOLOGIA DAS ALTERAÇÕES GLOBAIS DA UNIV. DE AVEIRO
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Analyses of the genomic variation to study cork oak evolution and adaptation : from past to future climatic changes
Publication . Pina-Martins; Paulo, Octávio, 1963-; Pappas, Georgios Joannis
Current scientific literature indicates that climate change will cause an average world temperature increase between 1 and 4ºC, along with changes in precipitation patterns and extreme weather events in the next 50 years. These are likely to have a negative impact for biodiversity in general, and forest ecosystems should be particularly affected, especially those in Mediterranean areas, like the cork oak (Quercus suber L.) “montados”. In order to understand how species can respond to such alterations, it is important to know their evolutionary history and genetic architecture of adaptive traits. Advances in sequencing technologies have relatively recently brought down the cost of sequencing per base pair to a point where even small research facilities can obtain genomic information of non-model organisms. These advances made SNP markers become the most abundant type of genetic variation in eukaryotic genomes, especially with the advent of Reduced Representation libraries such as RAD-Seq and GBS. Yet, despite their widespread use, SNP data analyses still bore its own set of bioinformatics challenges. While most of these are related with the practical aspects of the process, such as being able to handle very large datasets, or discriminate between neutral and non-neutral markers, some fundamental problems, like reproducibility are also important issues affecting research in this area. In this thesis, genomic and transcriptomic data from Q. suber was used to assess the evolutionary history of the species, detect the effects of natural selection across the cork oak’s distribution range and find any associations between the obtained markers and environmental variables. The main methodological contributions of this thesis are in the form of three software suites: (1) 4Pipe4, a software for automatically mining SNP markers from NGS data when no reference genome nor strain information is present, (2) NCBI Mass Sequence Downloader, a program to automate the downloading of large datasets from the NCBI databases, and (3) Structure_threader, a software to automate and parallelize analyses using several popular clustering analyses programs. All of these programs were developed with the intent to improve the automation and reproducibility value of the analysis processes they are meant to be part of. The main findings of this thesis are that (1) the evolutionary history and population structure of Q. suber is not as neatly structured as chloroplastidial markers indicate, (2) local adaptation plays and important role in the distribution of the species’ genetic variability, and (3) the cork oak may be better equipped, from a genetic point of view, to adapt to climate change than what previous studies based solely on ecological modelling indicated.
New insights into adaptation and population structure of cork oak using genotyping by sequencing
Publication . Pina-Martins, Francisco; Baptista, João; Pappas, Georgios; Paulo, Octávio S.
Species respond to global climatic changes in a local context. Understanding this process, including its speed and intensity, is paramount due to the pace at which such changes are currently occurring. Tree species are particularly interesting to study in this regard due to their long generation times, sedentarism, and ecological and economic importance. Quercus suber L. is an evergreen forest tree species of the Fagaceae family with an essentially Western Mediterranean distribution. Despite frequent assessments of the species' evolutionary history, large-scale genetic studies have mostly relied on plastidial markers, whereas nuclear markers have been used on studies with locally focused sampling strategies. In this work, "Genotyping by sequencing" is used to derive 1,996 single nucleotide polymorphism markers to assess the species' evolutionary history from a nuclear DNA perspective, gain insights into how local adaptation is shaping the species' genetic background, and to forecast how Q. suber may respond to global climatic changes from a genetic perspective. Results reveal (a) an essentially unstructured species, where (b) a balance between gene flow and local adaptation keeps the species' gene pool somewhat homogeneous across its distribution, but still allowing (c) variation clines for the individuals to cope with local conditions. "Risk of Non-Adaptedness" (RONA) analyses suggest that for the considered variables and most sampled locations, (d) the cork oak should not require large shifts in allele frequencies to survive the predicted climatic changes. Future directions include integrating these results with ecological niche modeling perspectives, improving the RONA methodology, and expanding its use to other species. With the implementation presented in this work, the RONA can now also be easily assessed for other organisms.
NCBI Mass Sequence Downloader–Large dataset downloading made easy
Publication . Pina Martins, Francisco; S. Paulo, Octávio
Structure_threader: An improved method for automation and parallelization of programs structure, fastStructure and MavericK on multicore CPU systems
Publication . Pina-Martins, Francisco; Silva, Diogo N.; Fino, Joana; Paulo, Octávio S.
Structure_threader is a program to parallelize multiple runs of genetic clustering software that does not make use of multithreading technology (structure, fastStructure and MavericK) on multicore computers. Our approach was benchmarked across multiple systems and displayed great speed improvements relative to the single-threaded implementation, scaling very close to linearly with the number of physical cores used. Structure_threader was compared to previous software written for the same task-ParallelStructure and StrAuto and was proven to be the faster (up to 25% faster) wrapper under all tested scenarios. Furthermore, Structure_threader can perform several automatic and convenient operations, assisting the user in assessing the most biologically likely value of 'K' via implementations such as the "Evanno," or "Thermodynamic Integration" tests and automatically draw the "meanQ" plots (static or interactive) for each value of K (or even combined plots). Structure_threader is written in python 3 and licensed under the GPLv3. It can be downloaded free of charge at https://github.com/StuntsPT/Structure_threader.
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Fundação para a Ciência e a Tecnologia
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SFRH/BD/51411/2011