Reference "Spatio-temporal patterns of genome evolution in allotetraploid species of the genus Oryza"

Reference ID

54909

Title

Spatio-temporal patterns of genome evolution in allotetraploid species of the genus Oryza

Source

Plant J, 2010, vol. , pp. -

Authors (17)

Ammiraju-J-S	Fan-C	Yu-Y	Song-X	Cranston-K-A
Pontaroli-A-C	Lu-F	Sanyal-A	Jiang-N	Rambo-T
Currie-J	Collura-K	Talag-J	Bennetzen-J-L	Chen-M
Jackson-S	Wing-R-A

Abstract

Summary Despite knowledge that polyploidy is widespread and a major evolutionary
force in flowering plant diversification, detailed comparative molecular studies
on polyploidy have been confined to only a few species and families. The genus
Oryza is composed of 23 species that are classified into ten distinct 'genome
types' (six diploid and four polyploid), and is emerging as a powerful new model
system to study polyploidy. Here we report the identification, sequence and
comprehensive comparative annotation of eight homoeologous genomes from a single
orthologous region (Adh1-Adh2) from four allopolyploid species representing each
of the known Oryza genome types (BC, CD, HJ and KL). Detailed comparative
phylogenomic analyses of these regions within and across species and ploidy
levels provided several insights into the spatio-temporal dynamics of genome
organization and evolution of this region in 'natural' polyploids of Oryza. The
major findings of this study are that: (i) homoeologous genomic regions within
the same nucleus experience both independent and parallel evolution, (ii)
differential lineage-specific selection pressures do not occur between
polyploids and their diploid progenitors, (iii) there have been no dramatic
structural changes relative to the diploid ancestors, (iv) a variation in the
molecular evolutionary rate exists between the two genomes in the BC complex
species even though the BC and CD polyploid species appear to have arisen <2
million years ago, and (v) there are no clear distinctions in the patterns of
genome evolution in the diploid versus polyploid species.