2 research outputs found
A Genotyping-by-Sequencing approach brings new insights into the population structure and local adaptation of Western Mediterranean Oaks
XIX ENBE Annual Meeting of the Portuguese Association for Evolutionary Biology, 18-19 December 2023, Lisboninfo:eu-repo/semantics/publishedVersio
A Genotyping-by-Sequencing Approach Brings New Insights into the Population Structure and Local Adaptation of Western Mediterranean Oaks.
The Mediterranean region has been described as a âclimate change hotspotâ, with increased
temperatures and decreased precipitation expected to affect the region in the coming decades.
Given the pace and intensity at which these changes are expected to happen, it becomes important
to understand species capacity to respond to climate change. Species response to environmental
change can happen through phenotypic plasticity, range shift, or genetic adaptation to their new
conditions. In order to understand a species adaptive capacity to respond to climate change, it is
important to disentangle how much of its genetic diversity is the result of population structure,
and how much results from the action of natural selection. This work involved samples of Cork
Oak (Quercus suber) and Holm Oak (Quercus ilex and Quercus rotundifolia), collected
throughout the species range, with special attention given to the Western Mediterranean basin.
Genotyping by Sequencing was employed to generate several genome wide Single Nucleotide
Polymorphism datasets, which were used (i) to investigate population structure using several
complementary approaches, and (ii) to detect evidence of local adaptation through a Landscape
Genomics approach involving the detection of genetic-environmental associations with several
bioclimatic variables. This work builds on previous analyses of Cork Oak SNP data, and is, to
our knowledge, the first attempt to use genome-wide nuclear genetic markers to uncover the
existence of population structure and signatures of local adaptation in Holm oak. Our results
reveal contrasting patterns of population structure and differentiation. Holm Oak shows a marked
pattern of population structure and considerable differentiation, especially between Q.
rotundifolia and Q. ilex samples, which brings support to the status of Q. ilex and Q. rotundifolia
as two genetically distinct species. Cork Oak, on the other hand, shows much less pronounced
population structuring, as reported in previous works based on nuclear genetic markers.
Furthermore, a considerable degree of differentiation is observed between Iberian and Moroccan
populations of Q. rotundifolia, which is not observed for Q. suber. Additionally, we uncover the
relatively unstructured nature of the Iberian Q. rotundifolia and Q. suber populations. We also
identified a considerable number of putative SNPs under selection in both species, showing
association with multiple bioclimatic variables related to temperature and precipitation.
Annotation of the genomic regions harboring these putative SNPs revealed several genes
potentially associated with heat and water stress. In general, these results build on previous
knowledge regarding the population structure of Cork Oak and bring new insights into the
population structure of Holm Oak, contributing towards the clarification of its taxonomy, which
up until this point has suffered from a lack of consistency. Regarding the detection of local
adaptation, our results serve as a first step in understanding the capacity of Cork Oak and Holm
Oak to respond to future climate change, opening the door to more complex analyses, such as
genomic prediction of maladaptation, which may help identify areas of the speciesâ distribution
especially sensitive to climate change, and inform future management efforts towards the
conservation of these species