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
BACKGROUND: Genome size evolution is a complex process influenced by polyploidization, satellite DNA accumulation, and expansion of retroelements. How this process could be affected by different reproductive strategies is still poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed differences in the number and distribution of major repetitive DNA elements in two closely related species, Silene latifolia and S. vulgaris. Both species are diploid and possess the same chromosome number (2n = 24), but differ in their genome size and mode of reproduction. The dioecious S. latifolia (1C = 2.70 pg DNA) possesses sex chromosomes and its genome is 2.5× larger than that of the gynodioecious S. vulgaris (1C = 1.13 pg DNA), which does not possess sex chromosomes. We discovered that the genome of S. latifolia is larger mainly due to the expansion of Ogre retrotransposons. Surprisingly, the centromeric STAR-C and TR1 tandem repeats were found to be more abundant in S. vulgaris, the species with the smaller genome. We further examined the distribution of major repetitive sequences in related species in the Caryophyllaceae family. The results of FISH (fluorescence in situ hybridization) on mitotic chromosomes with the Retand element indicate that large rearrangements occurred during the evolution of the Caryophyllaceae family. CONCLUSIONS/SIGNIFICANCE: Our data demonstrate that the evolution of genome size in the genus Silene is accompanied by the expansion of different repetitive elements with specific patterns in the dioecious species possessing the sex chromosomes.
- MeSH
- chromozomy rostlin MeSH
- délka genomu MeSH
- genetická variace MeSH
- genom rostlinný MeSH
- genomika MeSH
- hybridizace in situ fluorescenční MeSH
- hybridizace nukleových kyselin MeSH
- Magnoliopsida genetika MeSH
- mikrosatelitní repetice genetika MeSH
- modely genetické MeSH
- molekulární evoluce MeSH
- polyploidie MeSH
- repetitivní sekvence nukleových kyselin genetika MeSH
- rostlinné geny MeSH
- rostlinné proteiny genetika MeSH
- satelitní DNA genetika MeSH
- Silene klasifikace genetika MeSH
- výpočetní biologie metody MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
This review summarizes older as well as recent data about the model dioecious plant Silene latifolia. This plant has been the subject of more than one hundred years of research efforts and its most conspicuous property is huge and well differentiated heteromorphic sex chromosomes, XX in females and XY in males. Due to this property the S. latifolia sex chromosomes have been often used for cytogenetic studies as well as for flow sorting and laser microdissection. Nowadays S. latifolia is the focus of genomic studies, molecular mapping, phylogenetic and population genetics analyses.
- MeSH
- biologická evoluce MeSH
- chromozomy rostlin genetika MeSH
- cytogenetické vyšetření MeSH
- DNA rostlinná genetika MeSH
- epigeneze genetická MeSH
- fylogeneze MeSH
- genom rostlinný MeSH
- genomika MeSH
- hybridizace in situ fluorescenční MeSH
- modely genetické MeSH
- rozmnožování genetika MeSH
- Silene klasifikace genetika fyziologie MeSH
- transpozibilní elementy DNA genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
