YY males of the dioecious plant Mercurialis annua are fully viable but produce largely infertile pollen

What is it about?

The suppression of recombination between homologous sex chromosomes typically leads to their divergence and the degeneration of genes on the chromosome restricted to the heterogametic sex. This study compared the phenotypes of XY males of the plant <i>Mercurialis annua</i> with males bred to have a YY genotype. Although the two genotypes did not differ in vegetative morphology or viability, but YY males showed pollen abnormalities and were largely infertile. Male fertility in <i>M. annua</i> thus either requires an X chromosome or is sensitive to the dosage of relevant Y-linked genes.

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