Genomic insights into the Montseny brook newt (Calotriton arnoldi), a Critically Endangered glacial relict

Talavera, Adrián; Palmada Flores, Marc; Burriel Carranza, Bernat; Valbuena Ureña, Emilio; Mochales Riaño, Gabriel; Adams, Dean C.; Tejero Cicuéndez, Héctor, 1993-; Soler Membrives, Anna; Amat Orriols, Fèlix; Guinart, Daniel; Carbonell Buira, Francesc; Obón Losada, Elena; Marquès i Bonet, Tomàs, 1975-; Carranza Gil-Dolz del Castellar, Salvador

doi:http://dx.doi.org/10.1016/j.isci.2023.108665

Genomic insights into the Montseny brook newt (Calotriton arnoldi), a Critically Endangered glacial relict

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Talavera A, Palmada-Flores M, Burriel-Carranza B, Valbuena-Ureña E, Mochales-Riaño G, Adams DC, Tejero-Cicuéndez H, Soler-Membrives A, Amat F, Guinart D, Carbonell F, Obon E, Marquès-Bonet T, Carranza S. Genomic insights into the Montseny brook newt (Calotriton arnoldi), a Critically Endangered glacial relict. iScience. 2023 Dec 12;27(1):108665. DOI: 10.1016/j.isci.2023.108665

Abstract

The Montseny brook newt (Calotriton arnoldi), considered the most endangered amphibian in Europe, is a relict salamandrid species endemic to a small massif located in northeastern Spain. Although conservation efforts should always be guided by genomic studies, those are yet scarce among urodeles, hampered by the extreme sizes of their genomes. Here, we present the third available genome assembly for the order Caudata, and the first genomic study of the species and its sister taxon, the Pyrenean brook newt (Calotriton asper), combining whole-genome and ddRADseq data. Our results reveal significant demographic oscillations which accurately mirrored Europe's climatic history. Although severe bottlenecks have led to depauperate genomic diversity and long runs of homozygosity along a gigantic genome, inbreeding might have been avoided by assortative mating strategies. Other life history traits, however, seem to have been less advantageous, and the lack of land dispersal has driven to exceptional levels of population fragmentation.