CRISPR centromere fission generates stable neo-chromosomes with skewed inheritance in Arabidopsis

A preprint from bioRxiv describes the deliberate fission of a plant centromere using CRISPR-Cas9, producing what the authors term neo-chromosomes. The team targeted the centromeric satellite repeat array of Arabidopsis thaliana chromosome 3, splitting a single metacentric chromosome (one whose centromere sits in the middle) into two stable telocentric chromosomes — those whose centromeres sit at or near the tip.

The newly generated fission chromosomes rapidly acquired telomeres following the break, stabilising as heritable neo-chromosomes. The authors report that meiotic inheritance of these neo-chromosomes is distorted relative to the parental chromosome, providing empirical data on how centromere position influences segregation fidelity and potentially chromosome number evolution across species.

Centromere position varies widely across eukaryotes and is epigenetically defined by specialised histone variants (CENH3, also called CENP-A in animals). This study adds to a growing body of work using precise genome editing to interrogate how centromeres are established, maintained, and repositioned — questions with implications for understanding speciation, chromosome evolution, and the design of synthetic chromosomes.

This is a preprint and has not yet completed peer review. Findings should be interpreted with that caveat in mind. The work is of primary interest to chromosome biologists, plant geneticists, and evolutionary genomicists.