BACKGROUND: The rise and fall of the Y chromosome was demonstrated in animals but plants often possess the large evolutionarily young Y chromosome that is thought has expanded recently. Break-even points dividing expansion and shrinkage phase of plant Y chromosome evolution are still to be determined. To assess the size dynamics of the Y chromosome, we studied intraspecific genome size variation and genome composition of male and female individuals in a dioecious plant Silene latifolia, a well-established model for sex-chromosomes evolution. RESULTS: Our genome size data are the first to demonstrate that regardless of intraspecific genome size variation, Y chromosome has retained its size in S. latifolia. Bioinformatics study of genome composition showed that constancy of Y chromosome size was caused by Y chromosome DNA loss and the female-specific proliferation of recently active dominant retrotransposons. We show that several families of retrotransposons have contributed to genome size variation but not to Y chromosome size change. CONCLUSIONS: Our results suggest that the large Y chromosome of S. latifolia has slowed down or stopped its expansion. Female-specific proliferation of retrotransposons, enlarging the genome with exception of the Y chromosome, was probably caused by silencing of highly active retrotransposons in males and represents an adaptive mechanism to suppress degenerative processes in the haploid stage. Sex specific silencing of transposons might be widespread in plants but hidden in traditional hermaphroditic model plants.

• MeSH
• chromozomy rostlin * MeSH
• délka genomu MeSH
• DNA rostlinná * MeSH
• genom rostlinný MeSH
• hybridizace in situ fluorescenční MeSH
• koncové repetice MeSH
• mapování chromozomů MeSH
• molekulární evoluce * MeSH
• repetitivní sekvence nukleových kyselin MeSH
• retroelementy * MeSH
• sekvenční delece * MeSH
• Silene klasifikace   genetika   MeSH
• umlčování genů * MeSH
• variabilita počtu kopií segmentů DNA MeSH
• zastoupení bazí MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH