|
Introgressed
Introgression, also known as introgressive hybridization, in genetics is the transfer of genetic material from one species into the gene pool of another by the repeated backcrossing of an interspecific hybrid with one of its parent species. Introgression is a long-term process, even when artificial; it may take many hybrid generations before significant backcrossing occurs. This process is distinct from most forms of gene flow in that it occurs between two populations of different species, rather than two populations of the same species. Introgression also differs from simple hybridization. Simple hybridization results in a relatively even mixture; gene and allele frequencies in the first generation will be a uniform mix of two parental species, such as that observed in mules. Introgression, on the other hand, results in a complex, highly variable mixture of genes, and may only involve a minimal percentage of the donor genome. Definition Introgression or introgressive hybridizat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Denisovan
The Denisovans or Denisova hominins ( ) are an extinct species or subspecies of archaic human that ranged across Asia during the Lower and Middle Paleolithic, and lived, based on current evidence, from 285 thousand to 25 thousand years ago. Denisovans are known from few physical remains; consequently, most of what is known about them comes from DNA evidence. No formal species name has been established pending more complete fossil material. The first identification of a Denisovan individual occurred in 2010, based on mitochondrial DNA (mtDNA) extracted from a juvenile finger bone excavated from the Siberian Denisova Cave in the Altai Mountains in 2008. Nuclear DNA indicates close affinities with Neanderthals. The cave was also periodically inhabited by Neanderthals, but it is unclear whether Neanderthals and Denisovans ever cohabited in the cave. Additional specimens from Denisova Cave were subsequently identified, as was a single specimen from the Baishiya Karst Cave on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microcephalin
Microcephalin (MCPH1) is a gene that is expressed during fetal brain development. Certain mutations in ''MCPH1'', when homozygous, cause primary microcephaly—a severely diminished brain. Hence, it has been assumed that variants have a role in brain development. However, in normal individuals no effect on mental ability or behavior has yet been demonstrated in either this or another similarly studied microcephaly gene, '' ASPM''. However, an association has been established between normal variation in brain structure, as measured with MRI (i.e., primarily '' cortical surface area'' and total brain volume) but only in females, and common genetic variants within both the MCPH1 gene and another similarly studied microcephaly gene, ''CDK5RAP2''. Structure Microcephalin proteins contain the following three domains: * N-terminal BRCT domain * Central microcephalin protein domain () * C-terminal BRCT domain Expression in the brain MCPH1 is expressed in the fetal brain, in the develo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neanderthal
Neanderthals ( ; ''Homo neanderthalensis'' or sometimes ''H. sapiens neanderthalensis'') are an extinction, extinct group of archaic humans who inhabited Europe and Western and Central Asia during the Middle Pleistocene, Middle to Late Pleistocene. Neanderthal extinction occurred roughly 40,000 years ago with the immigration of modern humans (Cro-Magnons), but Neanderthals in Gibraltar may have persisted for thousands of years longer. The first recognised Neanderthal fossil, Neanderthal 1, was discovered in 1856 in the Neander Valley, Germany. At first, Neanderthal 1 was considered to be one of the racial hierarchy, lower races in accord with historical race concepts. As more fossils were discovered through the early 20th century, Neanderthals became characterised most especially by Marcellin Boule as a unique species of underdeveloped human. By the mid-20th century, human evolution was described as progressing from an apelike ancestor, through a "Neanderthal phase", ending ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hybrid PNGT
Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two different genetic parent strains * Hybrid (particle physics), a valence quark-antiquark pair and one or more gluons * Hybrid solar eclipse, a rare solar eclipse type * Hybrid star (other), with properties normally found in different types of stars Technology Transportation * Hybrid vehicle (other), various types of vehicles referred to as hybrids * Hybrid rail, an urban rail service for passengers using lightweight trains * Hybrid rocket, a rocket motor using propellants from two different states of matter * Hybrid shipping container, a container using phase change material in combination with the ability to recharge itself * Hybrid train, a locomotive, railcar, or train that uses an onboard rechargeable energy storage s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Biology And Evolution
''Molecular Biology and Evolution'' (''MBE'') is a monthly peer-reviewed scientific journal published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. It publishes work in the intersection of molecular biology and evolutionary biology. The founding editors were Walter Fitch and Masatoshi Nei; the present editors-in-chief are Brandon Gaut and Claudia Russo. Subject matter Evolution is the most fundamental of biological processes. MBE publishes patterns and processes that impact the evolution of life at molecular levels, across a full breadth of taxonomy, genomic organization, and functions, forms, and phenotypes. MBE's Methods, Resource, and Protocol sections include research tools that enable discoveries, while the Reviews and Perspectives synthesize different aspects of the evolutionary thought. Editorial process All MBE manuscripts are peer-reviewed. Decisions to publish are made by the Board of Editors, led by the Editors-in-Chief (Ei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosome
A chromosome is a package of DNA containing part or all of the genetic material of an organism. In most chromosomes, the very long thin DNA fibers are coated with nucleosome-forming packaging proteins; in eukaryotic cells, the most important of these proteins are the histones. Aided by chaperone proteins, the histones bind to and condense the DNA molecule to maintain its integrity. These eukaryotic chromosomes display a complex three-dimensional structure that has a significant role in transcriptional regulation. Normally, chromosomes are visible under a light microscope only during the metaphase of cell division, where all chromosomes are aligned in the center of the cell in their condensed form. Before this stage occurs, each chromosome is duplicated ( S phase), and the two copies are joined by a centromere—resulting in either an X-shaped structure if the centromere is located equatorially, or a two-armed structure if the centromere is located distally; the jo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agriculture
Agriculture encompasses crop and livestock production, aquaculture, and forestry for food and non-food products. Agriculture was a key factor in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to live in the cities. While humans started gathering grains at least 105,000 years ago, nascent farmers only began planting them around 11,500 years ago. Sheep, goats, pigs, and cattle were domesticated around 10,000 years ago. Plants were independently cultivated in at least 11 regions of the world. In the 20th century, industrial agriculture based on large-scale monocultures came to dominate agricultural output. , small farms produce about one-third of the world's food, but large farms are prevalent. The largest 1% of farms in the world are greater than and operate more than 70% of the world's farmland. Nearly 40% of agricultural land is found on farms larger than . However, five of every six farm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Troglomorphism
Troglomorphism is the morphological adaptation of an animal to living in the constant darkness of caves, characterised by features such as loss of pigment, reduced eyesight or blindness, and frequently with attenuated bodies or appendages. The terms troglobitic, stygobitic, stygofauna, troglofauna, and hypogean or hypogeic, are often used for cave-dwelling organisms. Troglomorphism occurs in molluscs, velvet worms, arthropods, fish, amphibians (notably cave salamanders) and reptiles. To date no mammals or birds have been found to live exclusively in caves. Pickerel frogs are classed as either trogloxenes, or possibly troglophiles. The first Troglobiont to be described was ''Leptodirus hochenwartii.'' Morphology of Troglomorphism Troglomorphic species must adapt to unique elements of subterranean life, like continual darkness, reduced season queues, and limited food availability. The reduction of characters like eyes and pigmentation is generally considered to be an evolutionary ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astroblepus
''Astroblepus'' is a genus of fish in the family Astroblepidae found in South America and Panama. This genus is the only member of its family. These catfishes are primarily found in torrential streams in the Andean area. ''Astroblepus pholeter'' and ''A. riberae'' are troglobites adapted to living in subterranean water systems. These species are typically small, less than . The largest species reaches . These fish have suckermouths like those of loricariids. They have two pairs of barbels, maxillary and nasal. The dorsal fin spine lacks a locking mechanism. These fish also have odontodes, tiny teeth on their skin. All species exhibit a conical, pointy type on their fin rays like that found in other loricarioids; other species also exhibit a blunt type that is only found on their skin. Some of these fish are able to live in high altitude and climb the faces of waterfalls. Their climbing ability comes from specially developed pelvic fins, as well as their suckermouths. In their N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Louisiana
Louisiana ( ; ; ) is a state in the Deep South and South Central regions of the United States. It borders Texas to the west, Arkansas to the north, and Mississippi to the east. Of the 50 U.S. states, it ranks 31st in area and 25th in population, with roughly 4.6 million residents. Reflecting its French heritage, Louisiana is the only U.S. state with political subdivisions termed parishes, which are equivalent to counties, making it one of only two U.S. states not subdivided into counties (the other being Alaska and its boroughs). Baton Rouge is the state's capital, and New Orleans, a French Louisiana region, is its most populous city with a population of about 363,000 people. Louisiana has a coastline with the Gulf of Mexico to the south; a large part of its eastern boundary is demarcated by the Mississippi River. Much of Louisiana's lands were formed from sediment washed down the Mississippi River, leaving enormous deltas and vast areas of coastal marsh a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iris (plant)
''Iris'' is a flowering plant genus of 310 accepted species with showy flowers. As well as being the scientific name, iris is also widely used as a common name for all ''Iris'' species, as well as some belonging to other closely related genera. A common name for some species is flags, while the plants of the subgenus '' Scorpiris'' are widely known as junos, particularly in horticulture. It is a popular garden flower. The often-segregated, monotypic genera '' Belamcanda'' (blackberry lily, ''I. domestica''), '' Hermodactylus'' (snake's head iris, ''I. tuberosa''), and ''Pardanthopsis'' (vesper iris, '' I. dichotoma'') are currently included in ''Iris''. Three ''Iris'' varieties are used in the ''Iris'' flower data set outlined by Ronald Fisher in his 1936 paper ''The use of multiple measurements in taxonomic problems'' as an example of linear discriminant analysis. Description Irises are perennial plants, growing from creeping rhizomes (rhizomatous irises) or, in drier c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canid Hybrid
Canid hybrids are the result of interbreeding between the species of the subfamily ''Caninae''. Genetic considerations The wolf-like canids are a group of large carnivores that are genetically closely related because they all possess 78 chromosomes, arranged in 39 pairs and are Karyology, karyologically indistinguishable from each other. The group includes the genera ''Canis'', ''Cuon'', ''Lupulella'' and ''Lycaon''. The members are the Dog, domestic dog ''(C. lupus familiaris)'', gray wolf (''C. lupus''), dingo (''C. lupus dingo''), coyote (''C. latrans''), golden jackal (''C. aureus''), African wolf (''C. lupaster''), Ethiopian wolf (''C. simensis''), dhole (''Cuon alpinus''), black-backed jackal (''Lupulella mesomelas''), side-striped jackal (''L. adusta'') and African wild dog (''Lycaon pictus''). Newly proposed members include the red wolf (''Canis rufus''), and the eastern wolf (''Canis lycaon''), subject to a resolution of the dispute as to whether these constitute separat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
