Fast Diploidization in Close Mesopolyploid Relatives ofArabidopsis
Open Access
- 1 July 2010
- journal article
- Published by Oxford University Press (OUP) in Plant Cell
- Vol. 22 (7), 2277-2290
- https://doi.org/10.1105/tpc.110.074526
Abstract
Mesopolyploid whole-genome duplication (WGD) was revealed in the ancestry of Australian Brassicaceae species with diploid-like chromosome numbers (n = 4 to 6). Multicolor comparative chromosome painting was used to reconstruct complete cytogenetic maps of the cryptic ancient polyploids. Cytogenetic analysis showed that the karyotype of the Australian Camelineae species descended from the eight ancestral chromosomes (n = 8) through allopolyploid WGD followed by the extensive reduction of chromosome number. Nuclear and maternal gene phylogenies corroborated the hybrid origin of the mesotetraploid ancestor and suggest that the hybridization event occurred ~6 to 9 million years ago. The four, five, and six fusion chromosome pairs of the analyzed close relatives of Arabidopsis thaliana represent complex mosaics of duplicated ancestral genomic blocks reshuffled by numerous chromosome rearrangements. Unequal reciprocal translocations with or without preceeding pericentric inversions and purported end-to-end chromosome fusions accompanied by inactivation and/or loss of centromeres are hypothesized to be the main pathways for the observed chromosome number reduction. Our results underline the significance of multiple rounds of WGD in the angiosperm genome evolution and demonstrate that chromosome number per se is not a reliable indicator of ploidy level.Keywords
This publication has 74 references indexed in Scilit:
- Genome comparisons reveal a dominant mechanism of chromosome number reduction in grasses and accelerated genome evolution in TriticeaeProceedings of the National Academy of Sciences of the United States of America, 2009
- Centromere repositioning in cucurbit species: Implication of the genomic impact from centromere activation and inactivationProceedings of the National Academy of Sciences of the United States of America, 2009
- The frequency of polyploid speciation in vascular plantsProceedings of the National Academy of Sciences of the United States of America, 2009
- A bicontinental origin of polyploid Australian/New Zealand Lepidium species (Brassicaceae)? Evidence from genomic in situ hybridizationAnnals of Botany, 2009
- Gene and genome duplications: the impact of dosage-sensitivity on the fate of nuclear genesChromosome Research, 2009
- Plants with double genomes might have had a better chance to survive the Cretaceous–Tertiary extinction eventProceedings of the National Academy of Sciences of the United States of America, 2009
- Genome size diversity in orchids: consequences and evolutionAnnals of Botany, 2009
- Allopolyploid speciation inPersicaria(Polygonaceae): Insights from a low-copy nuclear regionProceedings of the National Academy of Sciences of the United States of America, 2008
- The draft genome of the transgenic tropical fruit tree papaya (Carica papaya Linnaeus)Nature, 2008
- SCALLOPED Interacts with YORKIE, the Nuclear Effector of the Hippo Tumor-Suppressor Pathway in DrosophilaCurrent Biology, 2008