Dating the Colonisation and Source of Adaptive Genetic Variation in the Iago Sparrow (Passer iagoensis).
26 affiliations
- 1Section for Ecology, Biodiversity and Evolution (EBE), Department of Biosciences, University of Oslo, Oslo, Norway.
- 2Department of Bioinformatics and Genetics, Swedish Museum of Natural History, Stockholm, Sweden.
- 3SciLifeLab, Karolinska Institutet Science Park, Solna, Sweden.
- 4CISAS-Center for Research and Development in Agrifood Systems and Sustainability, Polytechnic University of Viana do Castelo, Viana do Castelo, Portugal.
- 5Natural History Museum, University of Oslo, Oslo, Norway.
- 6Faculty of Biology, Ludwig Maximilian University Munich, Planegg-Martinsried, Germany.
- 7Museum of Vertebrate Zoology, University of California, Berkeley, California, USA.
- 8Department of Integrative Biology, University of California, Berkeley, California, USA.
- 9Escuela de Biología, Universidad de San Carlos de Guatemala, Ciudad de Guatemala, Guatemala.
- 10CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBio, Laboratório Associado, Universidade do Porto, Vairão, Portugal.
- 11Department of Animal Behaviour, Bielefeld University, Bielefeld, Germany.
- 12Bell Museum and Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, Minnesota, USA.
- 13Zooekologi, Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden.
- 14Department of Cell and Molecular Biology, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Uppsala University, Uppsala, Sweden.
- 15Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK.
- 16Department of Evolution and Ecology, University of California, Davis, California, USA.
- 17Department of Molecular Biology and Biochemical Engineering, University Pablo de Olavide, Seville, Spain.
- 18Department of Biology, Lund University, Lund, Sweden.
- 19Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czechia.
- 20Department of Zoology, Faculty of Science, Charles University, Praha, Czechia.
- 21STRIX - Innovation for Global Biodiversity, Alagoa Office & Retail Center, Carcavelos, Portugal.
- 22ICBAS, Instituto de Ciência Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal.
- 23Instituto de Engenharia e Ciências do Mar, Universidade Técnica do Atlântico, Mindelo, Cabo Verde.
- 24School of Life Sciences, University of Nottingham, Nottingham, UK.
- 25MHNC-UP, Natural History and Science Museum of the University of Porto, Porto, Portugal.
- 26FitzPatrick Institute of African Ornithology, University of Cape Town, Rondebosch, South Africa.
Abstract
Ancestral adaptive variation is thought to play an important role in facilitating adaptation to insular environments. However, to properly evaluate its role, we need to determine the age of genetic variation. In this study, we investigate the Iago sparrow (Passer iagoensis), a generalist endemic to the Cabo Verde archipelago, to understand how genetic diversity is maintained in an island lineage where populations are likely ephemeral and adaptation to environmental extremes is ongoing. Using whole-genome sequencing and phenotypic data, we inferred the species' evolutionary history, population structure, and signatures of selection. Our results show that the Iago sparrow diverged from its closest mainland relative approximately 4.26 million years ago, although the colonisation likely occurred only around 2 million years ago. Population structure analyses reveal three distinct lineages, corresponding to geographic divisions within the archipelago, with the Rombos islets population exhibiting significant phenotypic divergence, particularly in bill morphology. Genome scans and phenotypic measurements identified signatures of divergent selection in genes associated with bill size (HMG20B) and bill shape (ALX1), suggesting adaptive evolution in response to local environmental conditions. Our ancestral recombination graph analysis provided temporal estimates for adaptive variation associated with these genes, suggesting that adaptive haplotypes observed in the Rombos population arose after colonisation of the archipelago. This contrasts with patterns described in Darwin's finches, where ancestral variation likely originated prior to colonisation. Our findings highlight the interplay of genetic drift, gene flow, and selection in shaping island species' genetic diversity. The Iago sparrow, a generalist thriving across diverse habitats, provides insights into the mechanisms that maintain genetic diversity in island lineages despite small population sizes and pronounced environmental heterogeneity.
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BibTeX
@article{cerca2026dating,
title = {{Dating the Colonisation and Source of Adaptive Genetic Variation in the Iago Sparrow (Passer iagoensis).}},
author = {José Cerca and Ângela M Ribeiro and Michael Matschiner and Rosa Alicia Jiménez and Hugo Pereira and Zheng Oong and Gabriel David and Per Unneberg and Yan Wong and Gabriele Maria Sgarlata and Pim Edelaar and Tomáš Albrecht and Glenn-Peter Saetre and Pedro Cardia and Augusto Faustino and Evandro P Lopes and Rauri C K Bowie and Mark Ravinet and Martim Melo},
journal = {Molecular ecology},
year = {2026},
month = nov,
doi = {10.1111/mec.70587},
url = {https://europepmc.org/article/MED/42974965},
note = {CC BY},
}
RIS
TY - JOUR
TI - Dating the Colonisation and Source of Adaptive Genetic Variation in the Iago Sparrow (Passer iagoensis).
AU - José Cerca
AU - Ângela M Ribeiro
AU - Michael Matschiner
AU - Rosa Alicia Jiménez
AU - Hugo Pereira
AU - Zheng Oong
AU - Gabriel David
AU - Per Unneberg
AU - Yan Wong
AU - Gabriele Maria Sgarlata
AU - Pim Edelaar
AU - Tomáš Albrecht
AU - Glenn-Peter Saetre
AU - Pedro Cardia
AU - Augusto Faustino
AU - Evandro P Lopes
AU - Rauri C K Bowie
AU - Mark Ravinet
AU - Martim Melo
PY - 2026
DA - 2026/11/01
JO - Molecular ecology
DO - 10.1111/mec.70587
UR - https://europepmc.org/article/MED/42974965
AB - Ancestral adaptive variation is thought to play an important role in facilitating adaptation to insular environments. However, to properly evaluate its role, we need to determine the age of genetic variation. In this study, we investigate the Iago sparrow (Passer iagoensis), a generalist endemic to the Cabo Verde archipelago, to understand how genetic diversity is maintained in an island lineage where populations are likely ephemeral and adaptation to environmental extremes is ongoing. Using whole-genome sequencing and phenotypic data, we inferred the species' evolutionary history, population structure, and signatures of selection. Our results show that the Iago sparrow diverged from its closest mainland relative approximately 4.26 million years ago, although the colonisation likely occurred only around 2 million years ago. Population structure analyses reveal three distinct lineages, corresponding to geographic divisions within the archipelago, with the Rombos islets population exhibiting significant phenotypic divergence, particularly in bill morphology. Genome scans and phenotypic measurements identified signatures of divergent selection in genes associated with bill size (HMG20B) and bill shape (ALX1), suggesting adaptive evolution in response to local environmental conditions. Our ancestral recombination graph analysis provided temporal estimates for adaptive variation associated with these genes, suggesting that adaptive haplotypes observed in the Rombos population arose after colonisation of the archipelago. This contrasts with patterns described in Darwin's finches, where ancestral variation likely originated prior to colonisation. Our findings highlight the interplay of genetic drift, gene flow, and selection in shaping island species' genetic diversity. The Iago sparrow, a generalist thriving across diverse habitats, provides insights into the mechanisms that maintain genetic diversity in island lineages despite small population sizes and pronounced environmental heterogeneity.
SN - 0962-1083
SN - 1365-294X
ER -