Turnover of retroelements and satellite DNA drives centromere reorganization over short evolutionary timescales in Drosophila
Centromeres reside in rapidly evolving, repeat-rich genomic regions, despite their essential function in chromosome segregation. This study of centromere evolution over short evolutionary timescales in Drosophila reveals dramatic centromere reorganization involving recurrent shifts between retroelements and satellite DNAs.
Scientists reveal evolutionary dynamics of centromeres in octoploid strawberries
The modern cultivated strawberry (Fragaria x ananassa) originates from interspecific hybridization between two octoploid wild species: F. virginiana and F. chiloensis. However, the differences in centromere characteristics and evolutionary patterns between wild and cultivated octoploids have remained poorly understood.
The complete genome assembly of Nicotiana benthamiana reveals the genetic and epigenetic landscape of centromeres | Nature Plants
Nicotiana benthamiana is a model organism widely adopted in plant biology. Its complete assembly remains unavailable despite several recent improvements. To further improve its usefulness, we generate and phase the complete 2.85 Gb genome assembly of allotetraploid N. benthamiana. We find that although Solanaceae centromeres are widely dominated by Ty3/Gypsy retrotransposons, satellite-based centromeres are surprisingly common in N. benthamiana, with 11 of 19 centromeres featured by megabase-scale satellite arrays. Interestingly, the satellite-enriched and satellite-free centromeres are extensively invaded by distinct Gypsy retrotransposons which CENH3 protein more preferentially occupies, suggestive of their crucial roles in centromere function. We demonstrate that ribosomal DNA is a major origin of centromeric satellites, and mitochondrial DNA could be employed as a core component of the centromere. Subgenome analysis indicates that the emergence of satellite arrays probably drives new centromere formation. Altogether, we propose that N. benthamiana centromeres evolved via neocentromere formation, satellite expansion, retrotransposon enrichment and mtDNA integration. This study generates and phases the complete genome assembly of a model plant Nicotiana benthamiana, revealing insights into the structure, epigenetic landscape and evolutionary dynamics of its centromeres following allotetraploidization.
This centromere map developed by Lv et al. and based on the
#rice super pan-
#genome highlights the structure and function of rice
#centromeres and provides avenues for future
#crop improvements.
https://doi.org/10.1111/jipb.13607 @wileyplantsci
#JIPB #PlantSci #CropSci #OpenAccess #SciComm #botany
Amelia Cervera 🧬
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