Silene
Sex Chromosomes
Chromosomes, Plant
Dianthus
Angiosperms
Genes, Mitochondrial
Immunohistochemical study of DNA methylation dynamics during plant development. (1/115)
DNA methylation represents one of the key processes that play an important role in the transcriptional control of gene expression. The role of cytosine methylation in plant development has been demonstrated by at least three different kinds of evidence: parent-specific expression of some genes in developing seeds, control of flowering time and floral morphogenesis, and correlation with silencing of intrusive DNA sequences (mobile genetic elements and transgenes). In this work global changes in DNA methylation during seed germination and shoot apical meristem development in Silene latifolia have been studied using an indirect immunohistochemical approach. The data presented show that a rapid decrease in global DNA methylation during seed germination occurs first in endosperm tissue and subsequently in the hypocotyl. Using 5-bromo-2'-deoxyuridine pulses, it has been demonstrated that these demethylation events occurred before cell division had begun. In the early post-germination period, a decrease in DNA methylation was detected in cotyledons, also before cell division was observed. Taken together, these results indicate that DNA demethylation takes place in a non-replicative way, probably by an active mechanism. The central zone of the shoot apical meristem remains highly methylated during the whole period of vegetative growth and in this region, only a low cell division activity was found. However, upon the transition of the shoot apical meristem to the floral bud, the meristem both decreased its high methylation status and its cells started to divide. These data indicate that the central zone of the shoot apical meristem can represent a relatively quiescent 'germ-line' which is activated upon flowering to form spores and gametes. (+info)Analysis and evolution of two functional Y-linked loci in a plant sex chromosome system. (2/115)
White campion (Silene latifolia) is one of the few examples of plants with separate sexes and with X and Y sex chromosomes. The presence or absence of the Y chromosome determines which type of reproductive organs--male or female--will develop. Recently, we characterized the first active gene located on a plant Y chromosome, SlY1, and its X-linked homolog, SlX1. These genes encode WD-repeat proteins likely to be involved in cell proliferation. Here, we report the characterization of a novel Y-linked gene, SlY4, which also has a homolog on the X chromosome, SlX4. Both SlY4 and SlX4 potentially encode fructose-2,6-bisphosphatases. A comparative molecular analysis of the two sex-linked loci (SlY1/SlX1 and SlY4/SlX4) suggests selective constraint on both X- and Y-linked genes and thus that both X- and Y-linked copies are functional. Divergence between SlY4 and SlX4 is much greater than that between the SlY1 and SlX1 genes. These results suggest that, as for human XY-linked genes, the sex-linked plant loci ceased recombining at different times and reveal distinct events in the evolutionary history of the sex chromosomes. (+info)Mapping of sex determination loci on the white campion (Silene latifolia) Y chromosome using amplified fragment length polymorphism. (3/115)
S. latifolia is a dioecious plant with morphologically distinct sex chromosomes. To genetically map the sex determination loci on the male-specific Y chromosome, we identified X-ray-induced sex determination mutants that had lost male traits. We used male-specific AFLP markers to characterize the extent of deletions in the Y chromosomes of the mutants. We then compared overlapping deletions to predict the order of the AFLP markers and to locate the mutated sex-determining genes. We found three regions on the Y chromosome where frequent deletions were significantly associated with loss of male traits. One was associated with hermaphroditic mutants. A second was associated with asexual mutants that lack genes needed for early stamen development and a third was associated with asexual mutants that lack genes for late stages of stamen development. Our observations confirmed a classical genetic prediction that S. latifolia has three dispersed male-determining loci on the Y chromosome, one for carpel suppression, one for early stamen development, and another for late stamen development. This AFLP map provides a framework for locating genes on the Y chromosome and for characterizing deletions on the Y chromosomes of potentially interesting mutants. (+info)Substitution rates in the X- and Y-linked genes of the plants, Silene latifolia and S. dioica. (4/115)
Theory predicts that selection should be less effective in the nonrecombining genes of Y-chromosomes, relative to the situation for genes on the other chromosomes, and this should lead to the accumulation of deleterious nonsynonymous substitutions. In addition, synonymous substitution rates may differ between X- and Y-linked genes because of the male-driven evolution effect and also because of actual differences in per-replication mutation rates between the sex chromosomes. Here, we report the first study of synonymous and nonsynonymous substitution rates on plant sex chromosomes. We sequenced two pairs of sex-linked genes, SlX1-SlY1 and SlX4-SlY4, from dioecious Silene latifolia and S. dioica, and their non-sex-linked homologues from nondioecious S. vulgaris and Lychnis flos-jovis, respectively. The rate of nonsynonymous substitutions in the SlY4 gene is significantly higher than that in the SlX4 gene. Silent substitution rates are also significantly higher in both Y-linked genes, compared with their X-linked homologues. The higher nonsynonymous substitution rate in the SlY4 gene is therefore likely to be caused by a mutation rate difference between the sex chromosomes. The difference in silent substitution rates between the SlX4 and SlY4 genes is too great to be explained solely by a higher per-generation mutation rate in males than females. It is thus probably caused by a difference in per-replication mutation rates between the sex chromosomes. This suggests that the local mutation rate can change in a relatively short evolutionary time. (+info)Linkage disequilibrium and phylogenetic congruence between chloroplast and mitochondrial haplotypes in Silene vulgaris. (5/115)
Both the chloroplast and mitochondrial genomes are used extensively in studies of plant population genetics and systematics. In the majority of angiosperms, the chloroplast DNA (cpDNA) and mitochondrial DNA (mtDNA) are each primarily transmitted maternally, but rare biparental transmission is possible. The extent to which the cpDNA and mtDNA are in linkage disequilibrium is argued to be dependent on the fidelity of co-transmission and the population structure. This study reports complete linkage disequilibrium between cpDNA and mtDNA haplotypes in 86 individuals from 17 populations of Silene vulgaris, a gynodioecious plant species. Phylogenetic analysis of cpDNA and mtDNA haplotypes within 14 individuals supports a hypothesis that the evolutionary histories of the chloroplasts and mitochondria are congruent within S. vulgaris, as might be expected if this association persists for long periods. This provides the first documentation of the evolutionary consequences of long-term associations between chloroplast and mitochondrial genomes within a species. Factors that contribute to the phylogenetic and linkage associations, as well as the potential for intergenomic hitchhiking resulting from selection on genes in one organellar genome are discussed. (+info)A plant pathogen reduces the enemy-free space of an insect herbivore on a shared host plant. (6/115)
An important mechanism in stabilizing tightly linked host-parasitoid and prey-predator interactions is the presence of refuges that protect organisms from their natural enemies. However, the presence and quality of refuges can be strongly affected by the environment. We show that infection of the host plant Silene latifolia by its specialist fungal plant pathogen Microbotryum violaceum dramatically alters the enemy-free space of a herbivore, the specialist noctuid seed predator Hadena bicruris, on their shared host plant. The pathogen arrests the development of seed capsules that serve as refuges for the herbivore's offspring against the specialist parasitoid Microplitis tristis, a major source of mortality of H. bicruris in the field. Pathogen infection resulted both in lower host-plant food quality, causing reduced adult emergence, and in twofold higher rates of parasitism of the herbivore. We interpret the strong oviposition preference of H. bicruris for uninfected plants in the field as an adaptive response, positioning offspring on refuge-rich, high-quality hosts. To our knowledge, this is the first demonstration that plant-inhabiting micro-organisms can affect higher trophic interactions through alteration of host refuge quality. We speculate that such interference can potentially destabilize tightly linked multitrophic interactions. (+info)Breeding system in the dichogamous hermaphrodite Silene acutifolia (Caryophyllaceae). (7/115)
The breeding system of the dichogamous hermaphrodite species Silene acutifolia, endemic to north-west Spain and north and central Portugal, is examined. Pollen germinability and style-stigma receptivity were analysed to determine whether protandry is a barrier to self-fertilization. By 48 h after anthesis, pollen germinability had declined to approx. 10 %. The short straight styles are not receptive when flowers first open. They gradually elongate and curve outwards, develop stigma papillae and become receptive. There is no clear separation between stigma and style: the stigma papillae appear in a line along the length of the style. Fruit set is high regardless of pollen source; however, seed set is significantly reduced after both spontaneous and facilitated autogamy. Seed set following spontaneous autogamy was 30 % (86 % in controls) in 1998 and 33 % (87 % in controls) in 1999. Seed set following facilitated autogamy was 62 % (86 % in controls) in 1998 and 67 % (89 % in controls) in 1999. Thus, separation of the male and female phases does not prevent production of seeds by self-pollination, although it does reduce the likelihood of this. Furthermore, results of the present experiments indicate that this species has no self-incompatibility mechanisms (self-compatibility index = 0.98). The selfing rate in the study population was 0.41, which is supported by the lack of self-incompatibility systems and by the incomplete protandry. (+info)Genetic and functional analysis of DD44, a sex-linked gene from the dioecious plant Silene latifolia, provides clues to early events in sex chromosome evolution. (8/115)
Silene latifolia is a dioecious plant with heteromorphic sex chromosomes. The sex chromosomes of S. latifolia provide an opportunity to study the early events in sex chromosome evolution because of their relatively recent emergence. In this article, we present the genetic and physical mapping, expression analysis, and molecular evolutionary analysis of a sex-linked gene from S. latifolia, DD44 (Differential Display 44). DD44 is homologous to the oligomycin sensitivity-conferring protein, an essential component of the mitochondrial ATP synthase, and is ubiquitously expressed in both sexes. We have been able to genetically map DD44 to a region of the Y chromosome that is genetically linked to the carpel-suppressing locus. Although we have physically mapped DD44 to the distal end of the long arm of the X chromosome using fluorescence in situ hybridization (FISH), DD44 maps to the opposite arm of the Y chromosome as determined by our genetic map. These data suggest that chromosomal rearrangements have occurred on the Y chromosome, which may have contributed to the genetic isolation of the Y chromosome. We discuss the implications of these results with respect to the structural and functional evolution of the S. latifolia Y chromosome. (+info)"Silene" is a genus of flowering plants in the family Caryophyllaceae. It includes over 700 species that are found worldwide, particularly in temperate regions. These plants are commonly known as catchflies or campions. They are usually herbaceous and can vary in size from small annuals to large perennials. The flowers of Silene species are typically radial symmetrical with five distinct petals, often with notched or lobed ends. Some species have inflated calyxes that enclose the flower buds, giving them a bladder-like appearance.
However, it's important to note that "Silene" is not a medical term and does not have a direct application in human health or medicine.
Y-linked genes are a type of sex-limited gene that is located on the Y chromosome. These genes are only present in males because they are passed from father to son through the paternal Y chromosome during reproduction. They are not paired with any corresponding genes on the X chromosome, and therefore, they do not have a counterpart to complement their function.
Y-linked genes play an essential role in sex determination and male development. For example, the SRY gene, which is located on the Y chromosome, encodes a protein that triggers testis development during embryonic development. Other Y-linked genes are involved in spermatogenesis, the process of producing sperm cells.
Since Y-linked genes are not present in females, they do not have any direct impact on female traits or characteristics. However, mutations in Y-linked genes can cause various genetic disorders that affect male fertility and development, such as Klinefelter syndrome, XYY syndrome, and other sex chromosome aneuploidies.
Sex chromosomes, often denoted as X and Y, are one of the 23 pairs of human chromosomes found in each cell of the body. Normally, females have two X chromosomes (46,XX), and males have one X and one Y chromosome (46,XY). The sex chromosomes play a significant role in determining the sex of an individual. They contain genes that contribute to physical differences between men and women. Any variations or abnormalities in the number or structure of these chromosomes can lead to various genetic disorders and conditions related to sexual development and reproduction.
Chromosomes in plants are thread-like structures that contain genetic material, DNA, and proteins. They are present in the nucleus of every cell and are inherited from the parent plants during sexual reproduction. Chromosomes come in pairs, with each pair consisting of one chromosome from each parent.
In plants, like in other organisms, chromosomes play a crucial role in inheritance, development, and reproduction. They carry genetic information that determines various traits and characteristics of the plant, such as its physical appearance, growth patterns, and resistance to diseases.
Plant chromosomes are typically much larger than those found in animals, making them easier to study under a microscope. The number of chromosomes varies among different plant species, ranging from as few as 2 in some ferns to over 1000 in certain varieties of wheat.
During cell division, the chromosomes replicate and then separate into two identical sets, ensuring that each new cell receives a complete set of genetic information. This process is critical for the growth and development of the plant, as well as for the production of viable seeds and offspring.
A gene in plants, like in other organisms, is a hereditary unit that carries genetic information from one generation to the next. It is a segment of DNA (deoxyribonucleic acid) that contains the instructions for the development and function of an organism. Genes in plants determine various traits such as flower color, plant height, resistance to diseases, and many others. They are responsible for encoding proteins and RNA molecules that play crucial roles in the growth, development, and reproduction of plants. Plant genes can be manipulated through traditional breeding methods or genetic engineering techniques to improve crop yield, enhance disease resistance, and increase nutritional value.
I'm sorry for any confusion, but "flowers" is not a term that has a medical definition. The term "flowers" is commonly used to refer to the reproductive structures of flowering plants (angiosperms), which are characterized by having both male and female reproductive organs or separate male and female flowers.
If you have any questions related to medical terminology or health conditions, I would be happy to try to help answer those for you!
DNA, or deoxyribonucleic acid, is the genetic material present in the cells of all living organisms, including plants. In plants, DNA is located in the nucleus of a cell, as well as in chloroplasts and mitochondria. Plant DNA contains the instructions for the development, growth, and function of the plant, and is passed down from one generation to the next through the process of reproduction.
The structure of DNA is a double helix, formed by two strands of nucleotides that are linked together by hydrogen bonds. Each nucleotide contains a sugar molecule (deoxyribose), a phosphate group, and a nitrogenous base. There are four types of nitrogenous bases in DNA: adenine (A), guanine (G), cytosine (C), and thymine (T). Adenine pairs with thymine, and guanine pairs with cytosine, forming the rungs of the ladder that make up the double helix.
The genetic information in DNA is encoded in the sequence of these nitrogenous bases. Large sequences of bases form genes, which provide the instructions for the production of proteins. The process of gene expression involves transcribing the DNA sequence into a complementary RNA molecule, which is then translated into a protein.
Plant DNA is similar to animal DNA in many ways, but there are also some differences. For example, plant DNA contains a higher proportion of repetitive sequences and transposable elements, which are mobile genetic elements that can move around the genome and cause mutations. Additionally, plant cells have cell walls and chloroplasts, which are not present in animal cells, and these structures contain their own DNA.
"Dianthus" is not a medical term, but a genus of flowering plants commonly known as "pinks." There are several species within the Dianthus genus, including garden pinks, sweet William, and carnations. These plants are native to Europe and Asia and are often cultivated for their attractive flowers, which can be white, pink, red, or purple. While Dianthus plants have no direct medical relevance, some species may have potential medicinal properties. For example, certain Dianthus species contain compounds with anti-inflammatory and antioxidant effects, but more research is needed to determine their safety and efficacy in humans.
Angiosperms, also known as flowering plants, are a group of plants that produce seeds enclosed within an ovary. The term "angiosperm" comes from the Greek words "angeion," meaning "case" or "capsule," and "sperma," meaning "seed." This group includes the majority of plant species, with over 300,000 known species.
Angiosperms are characterized by their reproductive structures, which consist of flowers. The flower contains male and female reproductive organs, including stamens (which produce pollen) and carpels (which contain the ovules). After fertilization, the ovule develops into a seed, while the ovary matures into a fruit, which provides protection and nutrition for the developing embryo.
Angiosperms are further divided into two main groups: monocots and eudicots. Monocots have one cotyledon or embryonic leaf, while eudicots have two. Examples of monocots include grasses, lilies, and orchids, while examples of eudicots include roses, sunflowers, and legumes.
Angiosperms are ecologically and economically important, providing food, shelter, and other resources for many organisms, including humans. They have evolved a wide range of adaptations to different environments, from the desert to the ocean floor, making them one of the most diverse and successful groups of plants on Earth.
Mitochondrial genes are a type of gene that is located in the DNA (deoxyribonucleic acid) found in the mitochondria, which are small organelles present in the cytoplasm of eukaryotic cells (cells with a true nucleus). Mitochondria are responsible for generating energy for the cell through a process called oxidative phosphorylation.
The human mitochondrial genome is a circular DNA molecule that contains 37 genes, including 13 genes that encode for proteins involved in oxidative phosphorylation, 22 genes that encode for transfer RNAs (tRNAs), and 2 genes that encode for ribosomal RNAs (rRNAs). Mutations in mitochondrial genes can lead to a variety of inherited mitochondrial disorders, which can affect any organ system in the body and can present at any age.
Mitochondrial DNA is maternally inherited, meaning that it is passed down from the mother to her offspring through the egg cell. This is because during fertilization, only the sperm's nucleus enters the egg, while the mitochondria remain outside. As a result, all of an individual's mitochondrial DNA comes from their mother.
Ecological and environmental processes refer to the complex interactions and relationships between living organisms and their physical surroundings. These processes can be biological, chemical, or physical in nature and they play a critical role in shaping the distribution and abundance of species, as well as the overall health and functioning of ecosystems.
Biological processes include things like predation, competition, and symbiosis, which describe how organisms interact with one another for resources and survival. Chemical processes involve the cycling of nutrients and energy through an ecosystem, such as the carbon cycle or nitrogen cycle. Physical processes include things like weather patterns, geological formations, and water cycles, which can all impact the distribution and diversity of species in an area.
Environmental processes can also refer to human activities that impact the environment, such as pollution, land use changes, and climate change. These processes can have significant consequences for both natural ecosystems and human health, making it essential to understand and manage them effectively.
Plastocyanin is a small, copper-containing protein that plays a crucial role in the photosynthetic electron transport chain. It functions as an electron carrier, facilitating the movement of electrons between two key protein complexes (cytochrome b6f and photosystem I) located in the thylakoid membrane of chloroplasts. Plastocyanin is a soluble protein found in the lumen of the thylakoids, and its copper ion serves as the site for electron transfer. The oxidized form of plastocyanin accepts an electron from cytochrome b6f and then donates it to photosystem I, helping to maintain the flow of electrons during light-dependent reactions in photosynthesis.