title: Compact genomes and complex evolution in the genus Brachypodium.
abstract: The temperate annual grass Brachypodium distachyon is a diploid species with a chromosome base number of 5. It is strikingly different from other Eurasian species of the genus, which are perennial and often polyploid, with the diploids typically having base numbers of 8 or 9. Previously, phylogenies indicated that B. distachyon split from the other species early in the evolution of the genus, while its genome sequence revealed that extensive synteny on a chromosomal scale had been maintained with rice, a tropical grass with a base number of 12. Here we show evidence that B. distachyon may have a homoploid origin, involving ancestral interspecific hybridisation, although it does not appear to be a component of any of the perennial Eurasian allopolyploids. Using a cytogenetic approach, we show that dysploidy in Brachypodium has not followed a simple progression.
authors.affiliation: Department of Plant Anatomy and Cytology, University of Silesia, Jagiellonska 28, 40-032, Katowice, Poland.
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Wolny
authors.forename: Karolina
authors.initials: K
authors.lastname: Lesniewska
authors.forename: Robert
authors.initials: R
authors.lastname: Hasterok
authors.forename: Tim
authors.initials: T
authors.lastname: Langdon
mesh_terms: D058431:Brachypodium / Q000145:classification / Q000235:genetics*; D032461:Chromosomes, Plant / Q000235:genetics; D019143:Evolution, Molecular; D018745:Genome, Plant; D008969:Molecular Sequence Data; D010802:Phylogeny; D011123:Polyploidy