AUTHOR=Udall Joshua A. , Long Evan , Ramaraj Thiruvarangan , Conover Justin L. , Yuan Daojun , Grover Corrinne E. , Gong Lei , Arick Mark A.  , Masonbrink Rick E. , Peterson Daniel G. , Wendel Jonathan F. 

TITLE=The Genome Sequence of Gossypioides kirkii Illustrates a Descending Dysploidy in Plants

JOURNAL=Frontiers in Plant Science

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.01541

DOI=10.3389/fpls.2019.01541

ISSN=1664-462X

ABSTRACT=<p>One of the extraordinary aspects of plant genome evolution is variation in chromosome number, particularly that among closely related species. This is exemplified by the cotton genus (<italic>Gossypium</italic>) and its relatives, where most species and genera have a base chromosome number of 13. The two exceptions are sister genera that have n = 12 (the Hawaiian <italic>Kokia</italic> and the East African and Madagascan <italic>Gossypioides</italic>). We generated a high-quality genome sequence of <italic>Gossypioides kirkii</italic> (n = 12) using PacBio, Bionano, and Hi-C technologies, and compared this assembly to genome sequences of <italic>Kokia</italic> (n = 12) and <italic>Gossypium</italic> diploids (n = 13). Previous analysis demonstrated that the directionality of their reduced chromosome number was through large structural rearrangements. A series of structural rearrangements were identified comparing the <italic>de novo G. kirkii</italic> genome sequence to genome sequences of <italic>Gossypium,</italic> including chromosome fusions and inversions. Genome comparison between <italic>G. kirkii</italic> and <italic>Gossypium</italic> suggests that multiple steps are required to generate the extant structural differences.</p>