Duplication and DNA segmental loss in the rice genome: implications for diploidization
Authors for correspondence: Jingchu LuoTel: +86 10 62757281Fax: +86 10 62759001Email: email@example.com
Song GeTel: +86 10 62591431x6097Fax: +86 10 62590843Email: firstname.lastname@example.org
- • Large-scale duplication events have been recently uncovered in the rice genome, but different interpretations were proposed regarding the extent of the duplications.
- • Through analysing the 370 Mb genome sequences assembled into 12 chromosomes of Oryza sativa subspecies indica, we detected 10 duplicated blocks on all 12 chromosomes that contained 47% of the total predicted genes. Based on the phylogenetic analysis, we inferred that this was a result of a genome duplication that occurred c. 70 million years ago, supporting the polyploidy origin of the rice genome. In addition, a segmental duplication was also identified involving chromosomes 11 and 12, which occurred c. 5 million years ago.
- • Following the duplications, there have been large-scale chromosomal rearrangements and deletions. About 30–65% of duplicated genes were lost shortly after the duplications, leading to a rapid diploidization.
- • Together with other lines of evidence, we propose that polyploidization is still an ongoing process in grasses of polyploidy origins.