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Genetic degeneration of old and young Y chromosomes in the flowering plant Rumex hastatulus

2014; National Academy of Sciences; Volume: 111; Issue: 21 Linguagem: Inglês

10.1073/pnas.1319227111

1091-6490

Josh Hough, Jesse D. Hollister, Wei Wang, Spencer C. H. Barrett, Stephen Wright,

Plant Virus Research Studies

Significance Evolutionary theory predicts that in dioecious organisms with sex chromosomes, suppressed X-Y recombination should lead to a loss of Y-chromosome gene content and function. However, the extent to which this process occurs in plants, where sex chromosomes evolved relatively recently, is poorly understood. We tested for Y degeneration in Rumex hastatulus , an annual plant that has both XY and XY 1 Y 2 sex chromosome systems. We found that Y-linked genes are undergoing degeneration despite their recent origin; they show a faster accumulation of amino acid substitutions, contain more unpreferred changes in codon usage, and are reduced in expression relative to X-linked alleles. Significantly, the magnitude of these effects depended on sex chromosome age, being greater for genes that have been nonrecombining for longer.