Andre Marques's team reports that Rhynchospora tenuis still makes pollen and seed yet shows no crossovers in more than 10,000 pollen nuclei. The Nature paper finds obligate genome-wide achiasmy in both sexes, with about 87 percent of seeds aborting unless the parental chromosome mix is restored.
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No crossovers in more than 10,000 pollen nuclei
The Max Planck Institute for Plant Breeding Research, dated 16 September 2026, says Andre Marques' Cologne-led team found the Brazilian beak-sedge Rhynchospora tenuis still makes pollen and seed but lost DNA reshuffling, with no crossovers in more than 10,000 pollen nuclei. The institute says about 87 percent of seeds abort and only offspring that restore the parental heterozygous chromosome combination survive, so surviving progeny match the mother. Cytological, genomic, single-cell and developmental analyses found no crossovers in male or female meiosis.[2]
This is plant meiosis, not a human finding
The peer-reviewed Nature study finds obligate genome-wide achiasmy in male and female meiosis of the sedge Rhynchospora tenuis; surviving offspring are genetically identical to the parents. Early meiotic axes form, synapsis fails, crossovers are undetectable, and univalents persist at metaphase I. Haplotype-specific transposable-element piles distort segregation toward larger, repeat-rich chromosomes. Fertilization yields viable seed only when translocation-compatible gametes meet, so surviving progeny restore the parental genotype and look clonal while remaining sexual.[1]
Sex continues; reshuffling does not
The Max Planck note and the Nature paper describe one sedge: pollen and seed are still made, crossovers are not detected, and the survivors look like the parent. A gamete filter restores that genotype. The authors propose that recombination loss, a low chromosome number, inverted meiosis and that filter keep segregation faithful. The same filter could also hide a low rate of cryptic crossovers. The Max Planck note and the Nature paper do not turn this into a human fertility result.[2], [1]
