Finding. In free-living kinetoplastids, the more of the cell's DNA that lives in the mitochondrion, the less of the nuclear genome is allowed to be junk. Zavadska, Richter and colleagues measure mitochondrial (kDNA) versus nuclear DNA with quantitative fluorescence in ten distant free-living isolates, infer nuclear non-coding fraction from imaging plus transcriptomes, and find the inverse they hypothesized. Compact, almost intron-free nuclei and sometimes nucleus-rivaling kinetoplasts are not two independent oddities. They look like a shared DNA budget.
Why this paper matters
Genome-size debates stall on cell volume and drift. Here mitochondrial DNA is on the ledger. If selection sees total DNA, a giant kinetoplast is a reason to shed nuclear non-coding sequence. That is a mitochondria-first genome-evolution sentence, even without a respiratory phenotype.
What they actually measured
Ten free-living lineages, fluorescence DNA fractions, transcriptome-informed non-coding estimates. A trend, not a fitted universal constant.
How to read the score
Low 70s. Real kDNA quantitative biology, no function. Confidence is medium for the causal story, higher for the trend as stated.
Caveats
Not parasitic kinetoplastids. Not finished assemblies. Fluorescence can lie about DNA mass. Do not turn this into a human mtDNA-copy-number rule.
What to do with it
If you argue about C-values, add a mitochondrial-DNA-fraction axis. If you work on trypanosome kDNA structure, this is a free-living comparative backdrop, not a minicircle mechanism.