Reconstruction of evolutionary trajectories of chromosomes unraveled independent genomic repatterning between Triticeae and Brachypodium

作者：Zhenyi Wang, Jinpeng Wang, Yuxin Pan, Tianyu Lei, Weina Ge, Li Wang, Lan Zhang, Yuxian Li, Kanglu Zhao, Tao Liu, Xiaoming Song, Jiaqi Zhang, Jigao Yu, Jingjing Hu, Xiyin Wang · 发表于：BMC Genomics · 年份：2019 · DOI：10.1186/s12864-019-5566-8 · 被引用次数：69 · 研究领域：Chromosomal and Genetic Variations、Plant Taxonomy and Phylogenetics、Genome Rearrangement Algorithms

BACKGROUND: After polyploidization, a genome may experience large-scale genome-repatterning, featuring wide-spread DNA rearrangement and loss, and often chromosome number reduction. Grasses share a common tetraploidization, after which the originally doubled chromosome numbers reduced to different chromosome numbers among them. A telomere-centric reduction model was proposed previously to explain chromosome number reduction. With Brachpodium as an intermediate linking different major lineages of grasses and a model plant of the Pooideae plants, we wonder whether it mediated the evolution from ancestral grass karyotype to Triticeae karyotype. RESULTS: By inferring the homology among Triticeae, rice, and Brachpodium chromosomes, we reconstructed the evolutionary trajectories of the Triticeae chromosomes. By performing comparative genomics analysis with rice as a reference, we reconstructed the evolutionary trajectories of Pooideae plants, including Ae. Tauschii (2n = 14, DD), barley (2n = 14), Triticum turgidum (2n = 4x = 28, AABB), and Brachypodium (2n = 10). Their extant Pooidea and Brachypodium chromosomes were independently produced after sequential nested chromosome fusions in the last tens of millions of years, respectively, after their split from rice. More frequently than would be expected by chance, in Brachypodium, the 'invading' and 'invaded' chromosomes are homoeologs, originating from duplication of a common ancestral chromosome, that is, with more extensive DNA-le...