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ITS-2
Internal transcribed spacer (ITS) is the spacer DNA situated between the small-subunit ribosomal RNA (rRNA) and large-subunit rRNA genes in the chromosome or the corresponding transcribed region in the polycistronic rRNA precursor transcript. Across life domains In bacteria and archaea, there is a single ITS, located between the 16S and 23S rRNA genes. Conversely, there are two ITSs in eukaryotes: ITS1 is located between 18S and 5.8S rRNA genes, while ITS2 is between 5.8S and 28S (in opisthokonts, or 25S in plants) rRNA genes. ITS1 corresponds to the ITS in bacteria and archaea, while ITS2 originated as an insertion that interrupted the ancestral 23S rRNA gene. Organization In bacteria and archaea, the ITS occurs in one to several copies, as do the flanking 16S and 23S genes. When there are multiple copies, these do not occur adjacent to one another. Rather, they occur in discrete locations in the circular chromosome. It is not uncommon in bacteria to carry tRNA gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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18S Ribosomal RNA
18S ribosomal RNA (abbreviated 18S rRNA) is a part of the ribosomal RNA in eukaryotes. It is a component of the Eukaryotic small ribosomal subunit (40S) and the cytosolic homologue of both the 12S ribosomal RNA, 12S rRNA in mitochondria and the 16S ribosomal RNA, 16S rRNA in plastids and prokaryotes. Similar to the prokaryotic 16S rRNA, the genes of the 18S ribosomal RNA have been widely used for Phylogenetics, phylogenetic studies and biodiversity screening of eukaryotes. Research history Along with the 28S ribosomal RNA, 28S and 5.8S ribosomal RNA, 5.8S rRNA in eukaryotes, the 18S rRNA was early identified as integral structural element of ribosomes which were first characterized by their sedimentation properties and named according to measured Svedberg, Svedberg units. Given its ubiquitous presence in eukaryotic life, the evolution of the 18S rRNA was soon proposed as marker for phylogenetics, phylogenetic studies to resolve the evolution of eukaryotes. Structure and function ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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18S RRNA
18S ribosomal RNA (abbreviated 18S rRNA) is a part of the ribosomal RNA in eukaryotes. It is a component of the Eukaryotic small ribosomal subunit (40S) and the cytosolic homologue of both the 12S rRNA in mitochondria and the 16S rRNA in plastids and prokaryotes. Similar to the prokaryotic 16S rRNA, the genes of the 18S ribosomal RNA have been widely used for phylogenetic studies and biodiversity screening of eukaryotes. Research history Along with the 28S and 5.8S rRNA in eukaryotes, the 18S rRNA was early identified as integral structural element of ribosomes which were first characterized by their sedimentation properties and named according to measured Svedberg units. Given its ubiquitous presence in eukaryotic life, the evolution of the 18S rRNA was soon proposed as marker for phylogenetic studies to resolve the evolution of eukaryotes. Structure and function The 18S ribosomal RNA is the structural RNA of the small subunit in the eukaryotic cytoplasmic ribosome. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Ribosomal DNA
The ribosomal DNA (rDNA) consists of a group of ribosomal RNA encoding genes and related regulatory elements, and is widespread in similar configuration in all domains of life. The ribosomal DNA encodes the non-coding ribosomal RNA, integral structural elements in the assembly of ribosomes, its importance making it the most abundant section of RNA found in cells of eukaryotes. Additionally, these segments include regulatory sections, such as a promoter specific to the RNA polymerase I, as well as both transcribed and non-transcribed spacer segments. Due to their high importance in the assembly of ribosomes for protein biosynthesis, the rDNA genes are generally highly conserved in molecular evolution. The number of copies can vary considerably per species. Ribosomal DNA is widely used for phylogenetic studies. Structure The ribosomal DNA includes all genes coding for the non-coding structural ribosomal RNA molecules. Across all domains of life, these are the structural ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Spacer DNA
Spacer DNA is a region of non-coding DNA between genes. The terms intergenic spacer (IGS) or non-transcribed spacer (NTS) are used particularly for the spacer DNA between the many tandemly repeated copies of the ribosomal RNA genes. In bacteria, spacer DNA sequences are only a few nucleotides long. In eukaryotes, they can be extensive and include repetitive DNA, comprising the majority of the DNA of the genome. In ribosomal DNA, there are spacers within and between gene clusters, called internal transcribed spacer (ITS) and external transcribed spacers (ETS), respectively. In animals, the mitochondrial DNA genes generally have very short spacers. In fungi A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ..., mitochondrial DNA spacers are common and variable in length, and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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External Transcribed Spacer
External transcribed spacer (ETS) refers to a piece of non-functional RNA, closely related to the internal transcribed spacer, which is situated outside structural ribosomal RNAs (rRNA) on a common precursor transcript. ETS sequences characteristic to an organism can be used to trace its phylogeny A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or Taxon, taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, M .... References {{genetics-stub DNA Phylogenetics de:Spacer (Biologie) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Leguminosae
Fabaceae () or Leguminosae,International Code of Nomenclature for algae, fungi, and plants. Article 18.5 states: "The following names, of long usage, are treated as validly published: ....Leguminosae (nom. alt.: Fabaceae; type: Faba Mill. Vicia L.; ... When the Papilionaceae are regarded as a family distinct from the remainder of the Leguminosae, the name Papilionaceae is conserved against Leguminosae." English pronunciations are as follows: , and . commonly known as the legume, pea, or bean family, is a large and agriculturally important of |
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Zea (plant)
''Zea'' is a genus of flowering plants in the Poaceae, grass family. The best-known species is ''Z. mays'' (variously called maize, corn, or Indian corn), one of the most important crops for human societies throughout much of the world. The four wild species are commonly known as teosintes and are native to Mesoamerica. Etymology ''Zea'' is derived from the Greek language, Greek name () for another cereal grain (possibly spelt).Gledhill, David (2008). "The Names of Plants". Cambridge University Press (CUP). (hardback), (paperback). pp 411 Recognized species The five accepted species names in the genus are: Maize (''Zea mays'') is further divided into four subspecies: ''Zea mays subsp. huehuetenangensis, Z. m. huehuetenangensis'', ''Zea mays subsp. mexicana, Z. m. mexicana'', ''Zea mays subsp. parviglumis, Z. m. parviglumis'' (Balsas teosinte, the ancestor of maize), and ''Zea mays subsp. mays, Z. m. mays''. The first three subspecies are teosintes; the last is maize, or co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Poaceae
Poaceae ( ), also called Gramineae ( ), is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos, the grasses of natural grassland and species cultivated in lawns and pasture. The latter are commonly referred to collectively as grass. With around 780 genera and around 12,000 species, the Poaceae is the fifth-largest plant family, following the Asteraceae, Orchidaceae, Fabaceae and Rubiaceae. The Poaceae are the most economically important plant family, including staple foods from domesticated cereal crops such as maize, wheat, rice, oats, barley, and millet for people and as feed for meat-producing animals. They provide, through direct human consumption, just over one-half (51%) of all dietary energy; rice provides 20%, wheat supplies 20%, maize (corn) 5.5%, and other grains 6%. Some members of the Poaceae are used as building materials ( bamboo, thatch, and straw); oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Arceuthobium
The genus ''Arceuthobium'', commonly called dwarf mistletoes, is a genus of 42 species of parasitic plants that parasitize members of Pinaceae and Cupressaceae in North America, Central America, Asia, Europe, and Africa. Of the 42 species that have been recognized, 39 and 21 of these are endemic to North America and the United States, respectively. They all have very reduced shoots and leaves (mostly reduced to scales) with the bulk of the plant living under the host's bark. Recently the number of species within the genus has been reduced to 26 as a result of more detailed genetic analysis. Description They are plant sexuality, dioecious, individual plants being either male or female. The fruit is unusual in that it builds up hydrostatic pressure internally when ripe and shoots the single sticky seed up to speeds nearly , an example of rapid plant movement. The Arceuthobium americanum, lodgepole pine dwarf mistletoe,'' Arceuthobium americanum, has been found to explosively-disp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Viscaceae
Viscaceae is a taxonomic family name of flowering plants. In this circumscription, the family includes the several genera of mistletoes. This family name is currently being studied and under review as in past decades, several systems of plant taxonomy recognized this family, notably the 1981 Cronquist system. However, the APG II system of 2003 does not recognize the family, treating it as a synonym of Santalaceae. This did not end the taxonomic debate among botanists and there are many that still think Viscaceae should be an accepted family name. According to the APG IV system, Der and Nickrent (2008) found seven well supported clades in Santalaceae, but relationships between these clades are still poorly understood. The traditional and cultural uses of species within the Viscaceae merit further attention. Clades or genera treated as belonging to the currently debated family name Viscaceae include: *''Arceuthobium The genus ''Arceuthobium'', commonly called dwarf mistleto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Compositae
Asteraceae () is a large family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the order Asterales. The number of species in Asteraceae is rivaled only by the Orchidaceae, and which is the larger family is unclear as the quantity of extant species in each family is unknown. The Asteraceae were first described in the year 1740 and given the original name Compositae. The family is commonly known as the aster, daisy, composite, or sunflower family. Most species of Asteraceae are herbaceous plants, and may be annual, biennial, or perennial, but there are also shrubs, vines, and trees. The family has a widespread distribution, from subpolar to tropical regions, in a wide variety of habitats. Most occur in hot desert and cold or hot semi-desert climates, and they are found on every continent but Antarctica. Their common primary characteristic is compound flower heads, technically known as capitula, consisting of sometimes hundred ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Asteraceae
Asteraceae () is a large family (biology), family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the Order (biology), order Asterales. The number of species in Asteraceae is rivaled only by the Orchidaceae, and which is the larger family is unclear as the quantity of Extant taxon, extant species in each family is unknown. The Asteraceae were first described in the year 1740 and given the original name Composita, Compositae. The family is commonly known as the aster, Daisy (flower), daisy, composite, or sunflower family. Most species of Asteraceae are herbaceous plants, and may be Annual plant, annual, Biennial plant, biennial, or Perennial plant, perennial, but there are also shrubs, vines, and trees. The family has a widespread distribution, from subpolar to tropical regions, in a wide variety of habitats. Most occur in Hot desert climate, hot desert and cold or hot Semi-arid climate, semi-desert climates, and they are found on ever ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |