Introgression facilitates rapid evolution of Galápagos tree finches

Introgression facilitates rapid evolution of Galápagos tree finches | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Introgression facilitates rapid evolution of Galápagos tree finches Matteo Sebastianelli Arbelaez, Erik Enbody, Carl-Johan Rubin, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8220844/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted You are reading this latest preprint version Abstract Adaptive radiations provide powerful models to study the origins of phenotypic novelty and species diversity. Darwin’s finches constitute a classic example of adaptive radiation, in which beak morphology is a key trait related to fitness. Here, we focused on Camarhynchus tree finches by analysing whole genomes in combination with morphological data to revisit long-standing questions regarding their origins raised before genetic evidence became available. Camarhynchus diversified recently, at least 100,000 Kya, yielding striking morphological differences despite shallow genetic divergence. We identified seven highly differentiated loci, including G03, a supergene affecting beak and body size. We reveal an unusual example of genomic mosaicism, in which autosomal differentiation between a large tree finch lineage and the small tree finch is restricted primarily to a single locus -(G03)- that approaches fixation. Contextualized in a broader phylogenetic framework, we reveal an unexpected diversity of G03 haplotypes, and show that the small and large G03 alleles diverged early in the radiation, suggesting a key genetic innovation enabling ecological expansion among species of Darwin’s finches. Our results establish Camarhynchus as a model example of speciation with gene flow, underscoring the broader role of hybridization in generating biodiversity. Biological sciences/Evolution/Speciation/Adaptive radiation Biological sciences/Genetics/Evolutionary biology Full Text Additional Declarations There is NO Competing Interest. Supplementary Files TreeFinchesSupplementaryMaterial101225.pdf Supplementary Material Cite Share Download PDF Status: Under Review Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8220844","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":558946778,"identity":"b57393d0-2d66-4c37-a1a3-0463131e0854","order_by":0,"name":"Matteo Sebastianelli 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