Contrasting pattern of subtelomeric satellites in the Cannabaceae family.

Introduction: Satellite DNA (satDNA) is a rapidly evolving component of plant genomes, typically found in (peri)centromeric, (sub)telomeric, and other heterochromatic regions. Due to their variability and species- or population-specific distribution, satDNA serves as valuable cytogenetic markers for studying chromosomal rearrangements and karyotype evolution among closely related species. Previous studies have identified species-specific subtelomeric repeats CS-1 in , HSR1 in , and HJSR in .

Sexy ways: approaches to studying plant sex chromosomes.

Sex chromosomes have evolved in many plant species with separate sexes. Current plant research is shifting from examining the structure of sex chromosomes to exploring their functional aspects. New studies are progressively unveiling the specific genetic and epigenetic mechanisms responsible for shaping distinct sexes in plants.

The Outline of Seed Silhouettes: A Morphological Approach to (Caryophyllaceae).

Seed morphology is an important source of information for plant taxonomy. Nevertheless, the characters under study are diverse, and a simple, unified method is lacking in the literature. A new method for the classification of seeds of the genus based on optical images and image analysis has recently been described on the basis of morphological measurements of the lateral seed views.

The evolution of huge Y chromosomes in and its sister, .

Microscopically dimorphic sex chromosomes in plants are rare, reducing our ability to study them. One difficulty has been the paucity of cultivatable species pairs for cytogenetic, genomic and experimental work. Here, we study the newly recognized sisters and , both with large Y chromosomes as we here show for .

Adaptive changes of the autosomal part of the genome in a dioecious clade of .

The genus brings many opportunities for the study of various processes involved in the evolution of dioecy and young sex chromosomes. Here we focus on a dioecious clade in subgenus and closely related species. This study provides improved support for monophyly of this clade (based on inclusion of further dioecious species) and a new estimate of its age ( 2.

Seed Morphology in Based on Geometric Models.

Seed description in morphology is often based on adjectives such as "spherical", "globular", or "reniform", but this does not provide a quantitative method. A new morphological approach based on the comparison of seed images with geometric models provides a seed description in species on a quantitative basis. The novelty of the proposed method is based in the comparison of the seed images with geometric models according to a cardioid shape.

Evolution of sex determination and heterogamety changes in section Otites of the genus Silene.

Switches in heterogamety are known to occur in both animals and plants. Although plant sex determination systems probably often evolved more recently than those in several well-studied animals, including mammals, and have had less time for switches to occur, we previously detected a switch in heterogamety in the plant genus Silene: section Otites has both female and male heterogamety, whereas S. latifolia and its close relatives, in a different section of the genus, Melandrium (subgenus Behenantha), all have male heterogamety.

Sex and the flower - developmental aspects of sex chromosome evolution.

Background: The evolution of dioecious plants is occasionally accompanied by the establishment of sex chromosomes: both XY and ZW systems have been found in plants. Structural studies of sex chromosomes are now being followed up by functional studies that are gradually shedding light on the specific genetic and epigenetic processes that shape the development of separate sexes in plants.

Scope: This review describes sex determination diversity in plants and the genetic background of dioecy, summarizes recent progress in the investigation of both classical and emerging model dioecious plants and discusses novel findings.

The evolutionary fate of the horizontally transferred agrobacterial mikimopine synthase gene in the genera Nicotiana and Linaria.

Few cases of spontaneously horizontally transferred bacterial genes into plant genomes have been described to date. The occurrence of horizontally transferred genes from the T-DNA of Agrobacterium rhizogenes into the plant genome has been reported in the genus Nicotiana and in the species Linaria vulgaris. Here we compare patterns of evolution in one of these genes (a gene encoding mikimopine synthase, mis) following three different events of horizontal gene transfer (HGT).

Evolution of sex determination systems with heterogametic males and females in silene.

The plant genus Silene has become a model for evolutionary studies of sex chromosomes and sex-determining mechanisms. A recent study performed in Silene colpophylla showed that dioecy and the sex chromosomes in this species evolved independently from those in Silene latifolia, the most widely studied dioecious Silene species. The results of this study show that the sex-determining system in Silene otites, a species related to S.

Comparative analysis of a plant pseudoautosomal region (PAR) in Silene latifolia with the corresponding S. vulgaris autosome.

Background: The sex chromosomes of Silene latifolia are heteromorphic as in mammals, with females being homogametic (XX) and males heterogametic (XY). While recombination occurs along the entire X chromosome in females, recombination between the X and Y chromosomes in males is restricted to the pseudoautosomal region (PAR). In the few mammals so far studied, PARs are often characterized by elevated recombination and mutation rates and high GC content compared with the rest of the genome.

Bisprimer--a program for the design of primers for bisulfite-based genomic sequencing of both plant and Mammalian DNA samples.

Plants and animals differ in the sequence context of the methylated sites in DNA. Plants exhibit cytosine methylation in CG, CHG, and CHH sites, whereas CG methylation is the only form present in mammals (with an exception of the early embryonic development). This fact must be taken into account in the design of primers for bisulfite-based genomic sequencing because CHG and CHH sites can remain unmodified.

What can we learn from tobacco and other Solanaceae about horizontal DNA transfer?

In eukaryotic organisms, horizontal gene transfer (HGT) is regarded as an important though infrequent source of reticulate evolution. Many confirmed instances of natural HGT involving multicellular eukaryotes come from flowering plants. This review intends to provide a synthesis of present knowledge regarding HGT in higher plants, with an emphasis on tobacco and other species in the Solanaceae family because there are numerous detailed reports concerning natural HGT events, involving various donors, in this family.

Dioecious Silene latifolia plants show sexual dimorphism in the vegetative stage.

Background: Prior to this study, no differences in gene expression between male and female dioecious plants in the vegetative state had been detected. Among dioecious plants displaying sexual dimorphism, Silene latifolia is one of the most studied species. Although many sexually dimorphic traits have been described in S.

Independent origin of sex chromosomes in two species of the genus Silene.

Here we introduce a new model species, Silene colpophylla, that could facilitate research of sex chromosome evolution and sex-determining systems. This species is related to the well-established dioecious plant model Silene latifolia. Our results show that S.

An interspecific hybrid as a tool to study phylogenetic relationships in plants using the GISH technique.

We established a new auxiliary phylogenetic approach based on genomic in situ hybridization technique (GISH). We used an interspecific hybrid Silene latifolia x Silene viscosa to compare two different genomes simultaneously on one slide. By using GISH with genomic DNA from another closely related species as a probe, we directly compared the level of relatedness between the genomes of the studied species and parental species.

Early events in the evolution of the Silene latifolia Y chromosome: male specialization and recombination arrest.

Understanding the origin and evolution of sex chromosomes requires studying recently evolved X-Y chromosome systems such as those in some flowering plants. We describe Y chromosome deletion mutants of Silene latifolia, a dioecious plant with heteromorphic sex chromosomes. The combination of results from new and previously described deletions with histological descriptions of their stamen development defects indicates the presence of two distinct Y regions containing loci with indispensable roles in male reproduction.

MK17, a specific marker closely linked to the gynoecium suppression region on the Y chromosome in Silene latifolia.

The aim of this work was to isolate new DNA markers linked to the Silene latifolia Y chromosome. To do this we created a chromosome-specific plasmid library after DOP-PCR amplification of laser-microdissected Y-chromosomes. The library screening led to the isolation of several clones yielding mostly to exclusive male specific hybridization signals.

Karyological analysis of an interspecific hybrid between the dioecious Silene latifolia and the hermaphroditic Silene viscosa.

The genus Silene is a good model for studying evolution of the sex chromosomes, since it includes species that are hermaphroditic and dioecious, while maintain a basic chromosome number of 2n = 24. For some combinations of Silene species it is possible to construct interspecific hybrids. Here, we present a detailed karyological analysis of a hybrid between the dioecious Silene latifolia as the maternal plant and a related species, hermaphroditic Silene viscosa, used as a pollen partner.

The inter-specific hybrid Silene latifolia x S. viscosa reveals early events of sex chromosome evolution.

The dioecious plant species Silene latifolia has a sex determination mechanism based on an active Y chromosome. Here, we used inter-specific hybrids in the genus Silene to study the effects of gene complexes on the Y chromosome. If the function of Y-linked genes has been maintained in the same state as in the hermaphrodite progenitor species, it should be possible to substitute such genes by genes coming from a related hermaphrodite species.

Comparison of the X and Y chromosome organization in Silene latifolia.

Here we compare gene orders on the Silene latifolia sex chromosomes. On the basis of the deletion mapping results (11 markers and 23 independent Y chromosome deletion lines used), we conclude that a part of the Y chromosome (covering a region corresponding to at least 23.9 cM on the X chromosome) has been inverted.

A gradual process of recombination restriction in the evolutionary history of the sex chromosomes in dioecious plants.

To help understand the evolution of suppressed recombination between sex chromosomes, and its consequences for evolution of the sequences of Y-linked genes, we have studied four X-Y gene pairs, including one gene not previously characterized, in plants in a group of closely related dioecious species of Silene which have an X-Y sex-determining system (S. latifolia, S. dioica, and S.