Uncovering the Mechanisms of Evolution:
Investigating Avian Diversification and Local Adaptation through Genomic Analysis
Speciation on islandsDuring my PhD at the National Museum of Natural Sciences (MNCN-CSIC) in Madrid (Spain) in Borja Mila's group, I focused on studying the genomic basis of evolution in avian species that colonized insular environments. Specifically, we compared insular and mainland counterparts to investigate if they have undergone convergent phenotypic and genomic adaptations following island colonization. Aditionally, I studied the diversification of the common chaffinch (Fringilla coelebs) in the Macaronesian region. Our results revealed that each population was a monophiletic clade and that the Atlantic archipelagos were sequentially colonized from the continent, starting in Azores, then Madeira and finally the Canary Islands, resulting in a species-level radiation. We also implemented species delimiation approaches combining phenotypic and genomic data. Based on these findings, we proposed a taxonomic revision in order to upgrade the current subspecies of North Africa, Azores, Madeira and the Canary Islands to the species level.
Interestingly, during the last step of this colonization, the Canary Islands, the chaffinch population on the island of La Palma expanded their range from the humid cloud forest to the dry pine forest. This provided an ideal opportunity to study the local adaptation process, which can drive divergence at small spatial scales when populations occupy contrasting habitats and dispersal is reduced or non random. Remarkably, birds inhabiting the two different habitats showed significant differences in diet, plumage coloration, and morphology, which were consistent with ecomorphological predictions. After implementing Genome-Wide Association Study (GWAS) and Genotype-Environment Association (GEA) methods we detected numerous loci involved in local adaptation spread across the genome, as expected for polygenic traits. Among the candidate genes we find some involved in morphological development, plumage coloration and metabolism, which are consistent with the phenotypic differences identified. These findings suggest that local adaptation plays a strong role in the chaffinch of La Palma, making it an excellent model for studying the evolutionary mechanisms driving adaptive phenotypic divergence. |
Understanding the genomic basis of pigmentation diversification in the rapid capuchino radiation
Currently, I am starting my first postdoc at the Cornell Lab of Ornithology in the group of Leonardo Campagna. In the upcoming years, I will perform genomic analysis of whole genomes to detect polymorphisms and structural variations related to differences in plumage coloration. We will use as a model system the capuchino seedeaters, which are a group of ten closely related species of South American finches in the genus Sporophila. Additionally, I will conduct transcriptomics analysis to identify differentially expressed genes in patches with different coloration between species.