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Glires
Glires (, Latin ''glīrēs'' 'dormice') is a clade (sometimes ranked as a grandorder) consisting of rodents and lagomorphs ( rabbits, hares, and pikas). The hypothesis that these form a monophyletic group has been long debated based on morphological evidence. Two morphological studies, published in 2001 and 2003, strongly support the monophyly of Glires. In particular, the 2003 study reported the discovery of fossil material of basal members of Glires, particularly the genera '' Mimotona'', ''Gomphos'', '' Heomys'', '' Matutinia'', '' Rhombomylus'', and '' Sinomylus''. Their description, in 2005, helped to bridge the gap between more typical rodents and lagomorphs. Data published in 2001, based on nuclear DNA, supported Glires as a sister of Euarchonta to form Euarchontoglires, but some genetic data from both nuclear and mitochondrial DNA have been less supportive. A study, published in 2007, investigating retrotransposon Retrotransposons (also called Class I transposab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simplicidentata
Simplicidentata is a group of mammals that includes the rodents (order Rodentia) and their closest extinct relatives. The term has historically been used as an alternative to Rodentia, contrasting the rodents (which have one pair of upper incisors) with their close relatives the lagomorphs (which have two). However, Simplicidentata is now defined as including all members of Glires (the clade formed by lagomorphs and rodents) that share a more recent common ancestor with living rodents than with living lagomorphs. Thus, Simplicidentata is a total group that is more inclusive than Rodentia, a crown group that includes all living rodents, their last common ancestor, and all its descendants. Under this definition, the loss of the second pair of upper incisors is a synapomorphic (shared derived) feature of Simplicidentata. The loss of the second upper premolar (P2) has also been considered as synapomorphic for Simplicidentata, but the primitive simplicidentate ''Sinomylus'' does have a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rodents
Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are native to all major land masses except for New Zealand, Antarctica, and several oceanic islands, though they have subsequently been introduced to most of these land masses by human activity. Rodents are extremely diverse in their ecology and lifestyles and can be found in almost every terrestrial habitat, including human-made environments. Species can be arboreal, fossorial (burrowing), saltatorial/richochetal (leaping on their hind legs), or semiaquatic. However, all rodents share several morphological features, including having only a single upper and lower pair of ever-growing incisors. Well-known rodents include mice, rats, squirrels, prairie dogs, porcupines, beavers, guinea pigs, and hamsters. Rabbits, hares, and pikas, who ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rodent
Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are native to all major land masses except for New Zealand, Antarctica, and several oceanic islands, though they have subsequently been introduced to most of these land masses by human activity. Rodents are extremely diverse in their ecology and lifestyles and can be found in almost every terrestrial habitat, including human-made environments. Species can be arboreal, fossorial (burrowing), saltatorial/richochetal (leaping on their hind legs), or semiaquatic. However, all rodents share several morphological features, including having only a single upper and lower pair of ever-growing incisors. Well-known rodents include mice, rats, squirrels, prairie dogs, porcupines, beavers, guinea pigs, and hamsters. Rabbits, hares, and pikas, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euarchontoglires
Euarchontoglires (synonymous with Supraprimates) is a clade and a superorder of mammals, the living members of which belong to one of the five following groups: rodents, lagomorphs, treeshrews, colugos, and primates. Evolutionary affinities within mammals The Euarchontoglires clade is based on DNA sequence analyses and retrotransposon markers that combine the clades Glires (Rodentia + Lagomorpha) and Euarchonta (Scandentia + Primates + Dermoptera). It is usually discussed without a taxonomic rank but has been called a cohort, magnorder, or superorder. Relations among the four cohorts (Euarchontoglires, Xenarthra, Laurasiatheria, Afrotheria) and the identity of the placental root remain controversial. So far, few, if any, distinctive anatomical features have been recognized that support Euarchontoglires; nor does any strong evidence from anatomy support alternative hypotheses. Although both Euarchontoglires and diprotodont marsupials are documented to possess a vermiform ap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euarchonta
The Euarchonta are a proposed grandorder of mammals: the order Scandentia (treeshrews), and its sister Primatomorpha mirorder, containing the Dermoptera or colugos and the primates (Plesiadapiformes and descendents). The term "Euarchonta" (meaning "true rulers") appeared in 1999, when molecular evidence suggested that the morphology-based Archonta should be trimmed down to exclude Chiroptera. Further DNA sequence analyses supported the Euarchonta hypothesis. Despite multiple papers pointing out that some mitochondrial sequences showed unusual properties (particularly murid rodents and hedgehogs) and were likely distorting the overall tree, and despite earlier studies showing near total congruence of mtDNA-based and nuclear-based trees when such sequences were excluded, some authors continued to produce misleading trees. A study investigating retrotransposon presence/absence data has claimed strong support for Euarchonta. Some interpretations of the molecular data link Primate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gomphos
''Gomphos'' is an extinct genus of early lagomorph from the early Eocene of the People's Republic of China, China and Mongolia. Gomphos was first named in 1975 from material found in the Gashato Formation. There are currently two species in this genus: ''G. elkema'', from the Greek word ''γόμφος'' (Romanized gomphos), which means "peg", but can also be used to signify molar teeth; and ''G. shevyrevae'' was named later in honour of the lead author who named the first original genus and species of ''Gomphos elkema''. Analysis supports ''Gomphos'' as one of the earliest lagomorphs, the group that includes rabbits, hares and pikas.Asher, Robert J., Jin Meng, John R. Wible, Malcolm C. McKenna, Guillermo W. Rougier, Demberlyn Dashzeveg, and Michael J. Novacek. "Stem Lagomorpha and the antiquity of Glires." Science 307, no. 5712 (2005): 1091-1094. It is likely that lagomorphs split off from the rest of the placental mammals around the Cretaceous-Palaeogene boundary. Sources * '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rabbit
Rabbits, also known as bunnies or bunny rabbits, are small mammals in the family Leporidae (which also contains the hares) of the order Lagomorpha (which also contains the pikas). ''Oryctolagus cuniculus'' includes the European rabbit species and its descendants, the world's 305 breeds of domestic rabbit. ''Sylvilagus'' includes 13 wild rabbit species, among them the seven types of cottontail. The European rabbit, which has been introduced on every continent except Antarctica, is familiar throughout the world as a wild prey animal and as a domesticated form of livestock and pet. With its widespread effect on ecologies and cultures, the rabbit is, in many areas of the world, a part of daily life—as food, clothing, a companion, and a source of artistic inspiration. Although once considered rodents, lagomorphs like rabbits have been discovered to have diverged separately and earlier than their rodent cousins and have a number of traits rodents lack, like two extra i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lagomorpha
The lagomorphs are the members of the taxonomic order Lagomorpha, of which there are two living families: the Leporidae (hares and rabbits) and the Ochotonidae ( pikas). The name of the order is derived from the Ancient Greek ''lagos'' (λαγώς, "hare") + ''morphē'' (μορφή, "form"). There are 110 recent species of lagomorph of which 109 are extant, including 34 species of pika, 42 species of rabbit, and 33 species of hare. Taxonomy and evolutionary history Other names used for this order, now considered synonymous, include: ''Duplicidentata'' - Illiger, 1811; ''Leporida'' - Averianov, 1999; ''Neolagomorpha'' - Averianov, 1999; ''Ochotonida'' - Averianov, 1999; and ''Palarodentia'' - Haeckel, 1895, Lilian, 2016. The evolutionary history of the lagomorphs is still not well understood. Until recently, it was generally agreed that '' Eurymylus'', which lived in eastern Asia and dates back to the late Paleocene or early Eocene, was an ancestor of the lagomorphs. More re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duplicidentata
The lagomorphs are the members of the taxonomic order Lagomorpha, of which there are two living families: the Leporidae (hares and rabbits) and the Ochotonidae (pikas). The name of the order is derived from the Ancient Greek ''lagos'' (λαγώς, "hare") + ''morphē'' (μορφή, "form"). There are 110 recent species of lagomorph of which 109 are extant, including 34 species of pika, 42 species of rabbit, and 33 species of hare. Taxonomy and evolutionary history Other names used for this order, now considered synonymous, include: ''Duplicidentata'' - Illiger, 1811; ''Leporida'' - Averianov, 1999; ''Neolagomorpha'' - Averianov, 1999; ''Ochotonida'' - Averianov, 1999; and ''Palarodentia'' - Haeckel, 1895, Lilian, 2016. The evolutionary history of the lagomorphs is still not well understood. Until recently, it was generally agreed that '' Eurymylus'', which lived in eastern Asia and dates back to the late Paleocene or early Eocene, was an ancestor of the lagomorphs. More rec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
10th Edition Of Systema Naturae
The 10th edition of ''Systema Naturae'' is a book written by Swedish naturalist Carl Linnaeus and published in two volumes in 1758 and 1759, which marks the starting point of zoological nomenclature. In it, Linnaeus introduced binomial nomenclature for animals, something he had already done for plants in his 1753 publication of '' Species Plantarum''. Starting point Before 1758, most biological catalogues had used polynomial names for the taxa included, including earlier editions of ''Systema Naturae''. The first work to consistently apply binomial nomenclature across the animal kingdom was the 10th edition of ''Systema Naturae''. The International Commission on Zoological Nomenclature therefore chose 1 January 1758 as the "starting point" for zoological nomenclature, and asserted that the 10th edition of ''Systema Naturae'' was to be treated as if published on that date. Names published before that date are unavailable, even if they would otherwise satisfy the rules. The only ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondrial DNA
Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial DNA is only a small portion of the DNA in a eukaryotic cell; most of the DNA can be found in the cell nucleus and, in plants and algae, also in plastids such as chloroplasts. Human mitochondrial DNA was the first significant part of the human genome to be sequenced. This sequencing revealed that the human mtDNA includes 16,569 base pairs and encodes 13 proteins. Since animal mtDNA evolves faster than nuclear genetic markers, it represents a mainstay of phylogenetics and evolutionary biology. It also permits an examination of the relatedness of populations, and so has become important in anthropology and biogeography. Origin Nuclear and mitochondrial DNA are thought to be of separate evolutionary origin, with the mtDNA being derive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retrotransposon
Retrotransposons (also called Class I transposable elements or transposons via RNA intermediates) are a type of genetic component that copy and paste themselves into different genomic locations ( transposon) by converting RNA back into DNA through the reverse transcription process using an RNA transposition intermediate. Through reverse transcription, retrotransposons amplify themselves quickly to become abundant in eukaryotic genomes such as maize (49–78%) and humans (42%). They are only present in eukaryotes but share features with retroviruses such as HIV, for example, discontinuous reverse transcriptase-mediated extrachromosomal recombination. These retrotransposons are regulated by a family of short non-coding RNAs termed as PIWI -element induced wimpy testisinteracting RNAs (piRNAs). piRNA is a recently discovered class of ncRNAs, which are in the length range of ~24-32 nucleotides. Initially, piRNAs were described as repeat-associated siRNAs (rasiRNAs) because of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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