Department of Plant Biology, University of California, Davis, Davis, United States; Genome Center, University of California, Davis, Davis, United States
Department of Plant Biology, University of California, Davis, Davis, United States; Genome Center, University of California, Davis, Davis, United States
Maruthachalam Ravi
School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, India
Genome Center, University of California, Davis, Davis, United States
Terezie Mandakova
Central European Institute of Technology, Masaryk University, Brno, Czech Republic
Mohan PA Marimuthu
Department of Plant Biology, University of California, Davis, Davis, United States; Genome Center, University of California, Davis, Davis, United States
Ian Korf
Genome Center, University of California, Davis, Davis, United States; Department of Molecular and Cellular Biology, University of California, Davis, Davis, United States
Martin A Lysak
Central European Institute of Technology, Masaryk University, Brno, Czech Republic
Department of Plant Biology, University of California, Davis, Davis, United States; Genome Center, University of California, Davis, Davis, United States
Simon WL Chan
Department of Plant Biology, University of California, Davis, Davis, United States; Gordon and Betty Moore Foundation, Howard Hughes Medical Institute, University of California, Davis, Davis, United States
Genome instability is associated with mitotic errors and cancer. This phenomenon can lead to deleterious rearrangements, but also genetic novelty, and many questions regarding its genesis, fate and evolutionary role remain unanswered. Here, we describe extreme chromosomal restructuring during genome elimination, a process resulting from hybridization of Arabidopsis plants expressing different centromere histones H3. Shattered chromosomes are formed from the genome of the haploid inducer, consistent with genomic catastrophes affecting a single, laggard chromosome compartmentalized within a micronucleus. Analysis of breakpoint junctions implicates breaks followed by repair through non-homologous end joining (NHEJ) or stalled fork repair. Furthermore, mutation of required NHEJ factor DNA Ligase 4 results in enhanced haploid recovery. Lastly, heritability and stability of a rearranged chromosome suggest a potential for enduring genomic novelty. These findings provide a tractable, natural system towards investigating the causes and mechanisms of complex genomic rearrangements similar to those associated with several human disorders.
