In five tested cancer cell lines, DNA-FISH and Aurora kinase B immunofluorescence identified paired mitotic daughters and quantified distinct ecDNA species. Inherited proportions were positively correlated (R = 0.4–0.71; P < 10⁻⁴ in each line): daughters receiving more of one species tended to receive more of another. Simulations predicted less correlation under independent random segregation or measured rare covalent fusions, supporting non-independent collective co-segregation—not directly demonstrating a mechanism. Individual ecDNA inheritance remains uneven. These results do not establish universal co-segregation, obligatory covalent fusion, molecular tethering, or clinical benefit.

Source: https://www.nature.com/articles/s41586-024-07861-8