Hybrid Drosophila cell lines show selective genome instabilities

Four independently derived hybrid Drosophila cell lines from Drosophila melanogaster × Drosophila simulans selectively lost the D. melanogaster Hmr allele and showed biased erosion of additional D. melanogaster regions.

• Why it matters: Post-zygotic reproductive isolation is linked to genomic conflict, but the specific incompatible genomic regions that are prone to be lost in hybrids remain unclear.
• What they did: Hybrid cell lines from an authentic interspecies cross were analyzed for allele loss, X-chromosome dosage compensation, rDNA amplification, nucleolar dominance drivers, and species-specific proteome differences in RNA-to-protein coefficient Kp.
• The result: The D. melanogaster X was dosage compensated via upregulation on the hemizygous D. simulans X, while D. melanogaster rDNA was paradoxically amplified; nucleolar dominance depended on relative rDNA copy number, and Kp differences revealed additional molecular conflict sources.