A yeast living ancestor reveals the origin of genomic introgressions
Journal article, 2020

Genome introgressions drive evolution across the animal1, plant2 and fungal3 kingdoms. Introgressions initiate from archaic admixtures followed by repeated backcrossing to one parental species. However, how introgressions arise in reproductively isolated species, such as yeast4, has remained unclear. Here we identify a clonal descendant of the ancestral yeast hybrid that founded the extant Saccharomyces cerevisiae Alpechin lineage5, which carries abundant Saccharomyces paradoxus introgressions. We show that this clonal descendant, hereafter defined as a ‘living ancestor’, retained the ancestral genome structure of the first-generation hybrid with contiguous S. cerevisiae and S. paradoxus subgenomes. The ancestral first-generation hybrid underwent catastrophic genomic instability through more than a hundred mitotic recombination events, mainly manifesting as homozygous genome blocks generated by loss of heterozygosity. These homozygous sequence blocks rescue hybrid fertility by restoring meiotic recombination and are the direct origins of the introgressions present in the Alpechin lineage. We suggest a plausible route for introgression evolution through the reconstruction of extinct stages and propose that genome instability allows hybrids to overcome reproductive isolation and enables introgressions to emerge.


Melania D’Angiolo

University of Côte d'Azur

Matteo De Chiara

University of Côte d'Azur

Jia Xing Yue

University of Côte d'Azur

Agurtzane Irizar

University of Côte d'Azur

Simon Stenberg

University of Gothenburg

Norwegian University of Life Sciences

Karl Persson

University of Gothenburg

Agnès Llored

University of Côte d'Azur

Benjamin P. Barré

University of Côte d'Azur

Joseph Schacherer

University of Strasbourg

Roberto Marangoni

University of Pisa

Eric Gilson

University of Côte d'Azur

Jonas Warringer

University of Gothenburg

Gianni Liti

University of Côte d'Azur


0028-0836 (ISSN) 1476-4687 (eISSN)

Vol. 587 7834 420-425

Subject Categories

Evolutionary Biology

Astronomy, Astrophysics and Cosmology

Structural Biology



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