RT Journal Article
SR Electronic
T1 Genomic analyses of the <em>Linum</em> distyly supergene reveal convergent evolution at the molecular level
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2022.05.27.493681
DO 10.1101/2022.05.27.493681
A1 Juanita Gutiérrez-Valencia
A1 Marco Fracassetti
A1 Emma L. Berdan
A1 Ignas Bunikis
A1 Lucile Soler
A1 Jacques Dainat
A1 Verena E. Kutschera
A1 Aleksandra Losvik
A1 Aurélie Désamoré
A1 P. William Hughes
A1 Alireza Foroozani
A1 Benjamin Laenen
A1 Edouard Pesquet
A1 Mohamed Abdelaziz
A1 Olga Vinnere Pettersson
A1 Björn Nystedt
A1 Adrian Brennan
A1 Juan Arroyo
A1 Tanja Slotte
YR 2022
UL http://biorxiv.org/content/early/2022/05/29/2022.05.27.493681.abstract
AB Supergenes govern balanced polymorphisms in a wide range of systems. The reciprocal placement of stigmas and anthers in pin and thrum floral morphs of distylous species constitutes an iconic example of a balanced polymorphism governed by a supergene, the distyly S-locus. Recent studies have shown that the Primula and Turnera distyly supergenes are both hemizygous in thrums, but it remains unknown if hemizygosity is pervasive among distyly S-loci. Here we have characterized the genetic architecture and evolution of the distyly supergene in Linum by generating a chromosome-level genome assembly of Linum tenue, followed by the identification of the S-locus using population genomic data. We show that hemizygosity and thrum-specific expression of S-linked genes, including a pistil-expressed candidate gene for style length, are major features of the Linum S-locus. Structural variation is likely instrumental for recombination suppression, and although the non-recombining dominant haplotype has accumulated transposable elements, S-linked genes are not under relaxed purifying selection. Our findings reveal remarkable convergence in the genetic architecture and evolution of independently derived distyly supergenes. The chromosome-level genome assembly and detailed characterization of the distyly S-locus in L. tenue will facilitate elucidation of molecular mechanisms underlying the different forms of flowers described by Darwin.Competing Interest StatementThe authors have declared no competing interest.