Doubling genome size without polyploidization: dynamics of retrotransposition-driven genomic expansions in Oryza australiensis, a wild relative of rice.
Retrotransposons are the main components of eukaryotic genomes, representing up to 80% of some large plant genomes. These mobile elements transpose via a "copy and paste" mechanism, thus increasing their copy number while active. Their accumulation is now accepted as the main factor of genome size increase in higher eukaryotes, besides polyploidy. However, the dynamics of this process are poorly understood. In this study, we show that Oryza australiensis, a wild relative of the Asian cultivated rice O. sativa, has undergone recent bursts of three LTR-retrotransposon families. This genome has accumulated more than 90,000 retrotransposon copies during the last three million years, leading to a rapid twofold increase of its size. In addition, phenetic analyses of these retrotransposons clearly confirm that the genomic bursts occurred posterior to the radiation of the species. This provides direct evidence of retrotransposon-mediated variation of genome size within a plant genus.
Piegu
Benoit
B
Laboratoire Génome et Développement des Plantes, UMR 5096 CNRS-IRD, Université de Perpignan, Perpignan 66860, France.
Guyot
Romain
R
Picault
Nathalie
N
Roulin
Anne
A
Sanyal
Abhijit
A
Saniyal
Abhijit
A
Kim
Hyeran
H
Collura
Kristi
K
Brar
Darshan S
DS
Jackson
Scott
S
Wing
Rod A
RA
Panaud
Olivier
O
D001483:Base Sequence; D015139:Blotting, Southern; D002874:Chromosome Mapping; D022202:Chromosomes, Artificial, Bacterial; D016000:Cluster Analysis; D020440:Gene Duplication; D018745:Genome, Plant / Q000235:genetics*; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics*; D010802:Phylogeny; D018626:Retroelements / Q000235:genetics*; D017422:Sequence Analysis, DNA
D018626:Retroelements