Telomere‐centric genome repatterning determines recurring chromosome number reductions during the evolution of eukaryotes. Issue 1 (20th August 2014)

• Record Type: Journal Article
• Authors: Wang, Xiyin; Jin, Dianchuan; Wang, Zhenyi; Guo, Hui; Zhang, Lan; Wang, Li; Li, Jingping; Paterson, Andrew H.
• Is Part Of: New phytologist. Volume 205:Issue 1(2015)
• Page Start: 378
• Page End: 389
• Publication Date: 2014-08-20
• Subjects: Arabidopsis -- centromere -- chromosome number reduction -- genome repatterning -- grasses -- polyploidy -- telomere; Botany -- Periodicals; 580
• DOI: 10.1111/nph.12985
• Languages: English
• ISSNs: 0028-646X

Abstract

Summary: Whole‐genome duplication (WGD) is central to the evolution of many eukaryotic genomes, in particular rendering angiosperm (flowering plant) genomes much less stable than those of animals. Following repeated duplication/triplication(s), angiosperm chromosome numbers have usually been restored to a narrow range, as one element in a 'diploidization' process that re‐establishes diploid heredity. In several angiosperms affected by WGD, we show that chromosome number reduction (CNR) is best explained by intra‐ and/or inter‐chromosomal crossovers to form new chromosomes that utilize the existing telomeres of 'invaded' and centromeres of 'invading' chromosomes, the alternative centromeres and telomeres being lost. Comparison with the banana ( Musa acuminata ) genome supports a 'fusion model' for the evolution of rice ( Oryza sativa ) chromosomes 2 and 3, implying that the grass common ancestor had seven chromosomes rather than the five implied by a 'fission model.' The 'invading' and 'invaded' chromosomes are frequently homoeologs, originating from duplication of a common ancestral chromosome and with greater‐than‐average DNA‐level correspondence to one another. Telomere‐centric CNR following recursive WGD in plants is also important in mammals and yeast, and may be a general mechanism of restoring small linear chromosome numbers in higher eukaryotes.