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Phenocopy
A phenocopy is a variation in phenotype (generally referring to a single trait) which is caused by environmental conditions (often, but not necessarily, during the organism's development), such that the organism's phenotype matches a phenotype which is determined by genetic factors. It is not a type of mutation, as it is non-hereditary. The term was coined by Richard Goldschmidt in 1935. He used it to refer to forms, produced by some experimental procedure, whose appearance duplicates or copies the phenotype of some mutant or combination of mutants. Examples The butterfly genus ''Vanessa'' can change phenotype based on the local temperature. If introduced to Lapland they mimic butterflies localised to this area; and if localised to Syria they mimic butterflies of this area. The larvae of ''Drosophila melanogaster'' have been found to be particularly vulnerable to environmental factors which produce phenocopies of known mutations; these factors include temperature, shock, radiati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genocopy
Genocopy is a trait that is a phenotypic copy of a genetic trait but is caused by a different genotype. When a genetic mutation or genotype in one locus results in a phenotype similar to one that is known to be caused by another mutation or genotype in another locus, it is said to be a genocopy. However, genocopies may also be referred to as "genetic mimics", in which the same mutation or specific genotype can result in two unique phenotypes in two different patients. The term “Genocopy” was coined by Dr. H. Nachstheim in 1957, in which he discusses “false” phenocopies. In comparison to when a phenotype is the result of an environmental condition that had the same effect as a previously known genetic factor such as mutation. While offspring may inherit specific mutations or genotypes that result in genocopies, phenocopies are not heritable. Two types of elliptocytosis that are genocopies of each other, but are distinguished by the fact that one is linked to the Rh blood grou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenotype
In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological properties, its behavior, and the products of behavior. An organism's phenotype results from two basic factors: the expression of an organism's genetic code, or its genotype, and the influence of environmental factors. Both factors may interact, further affecting phenotype. When two or more clearly different phenotypes exist in the same population of a species, the species is called polymorphic. A well-documented example of polymorphism is Labrador Retriever coloring; while the coat color depends on many genes, it is clearly seen in the environment as yellow, black, and brown. Richard Dawkins in 1978 and then again in his 1982 book ''The Extended Phenotype'' suggested that one can regard bird nests and other built structures such as cad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trait (biological)
A phenotypic trait, simply trait, or character state is a distinct variant of a phenotypic characteristic of an organism; it may be either inherited or determined environmentally, but typically occurs as a combination of the two.Lawrence, Eleanor (2005) ''Henderson's Dictionary of Biology''. Pearson, Prentice Hall. For example, having eye color is a ''character'' of an organism, while blue, brown and hazel versions of eye colour are ''traits''. The term ''trait'' is generally used in genetics, often to describe phenotypic expression of different combinations of alleles in different individual organisms within a single population, such as the famous purple vs. white flower coloration in Gregor Mendel's pea plants. By contrast, in systematics, the term is ''character state'' is employed to describe features that represent fixed diagnostic differences among taxa, such as the absence of tails in great apes, relative to other primate groups. Definition A phenotypic trait is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Developmental Biology
Developmental biology is the study of the process by which animals and plants grow and develop. Developmental biology also encompasses the biology of Regeneration (biology), regeneration, asexual reproduction, metamorphosis, and the growth and differentiation of stem cells in the adult organism. Perspectives The main processes involved in the embryogenesis, embryonic development of animals are: tissue patterning (via regional specification and patterned cellular differentiation, cell differentiation); tissue growth; and tissue morphogenesis. * Regional specification refers to the processes that create the spatial patterns in a ball or sheet of initially similar cells. This generally involves the action of cytoplasmic determinants, located within parts of the fertilized egg, and of inductive signals emitted from signaling centers in the embryo. The early stages of regional specification do not generate functional differentiated cells, but cell populations committed to developing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mutation
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mitosis, or meiosis or other types of damage to DNA (such as pyrimidine dimers caused by exposure to ultraviolet radiation), which then may undergo error-prone repair (especially microhomology-mediated end joining), cause an error during other forms of repair, or cause an error during replication (translesion synthesis). Mutations may also result from insertion or deletion of segments of DNA due to mobile genetic elements. Mutations may or may not produce detectable changes in the observable characteristics (phenotype) of an organism. Mutations play a part in both normal and abnormal biological processes including: evolution, cancer, and the development of the immune system, including junctional diversity. Mutation is the ultimate source o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richard Goldschmidt
Richard Benedict Goldschmidt (April 12, 1878 – April 24, 1958) was a German-born American geneticist. He is considered the first to attempt to integrate genetics, development, and evolution. He pioneered understanding of reaction norms, genetic assimilation, dynamical genetics, sex determination, and heterochrony.Dietrich, Michael R. (2003)Richard Goldschmidt: hopeful monsters and other 'heresies.'''Nature Reviews Genetics'' 4 (Jan.): 68-74. Controversially, Goldschmidt advanced a model of macroevolution through macromutations popularly known as the "Hopeful Monster" hypothesis. Goldschmidt also described the nervous system of the nematode, a piece of work that influenced Sydney Brenner to study the wiring diagram of ''Caenorhabditis elegans'', winning Brenner and his colleagues the Nobel Prize in 2002. Childhood and education Goldschmidt was born in Frankfurt-am-Main, Germany to upper-middle class parents of Ashkenazi Jewish heritage. He had a classical education and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vanessa (butterfly)
''Vanessa'' is a genus of brush-footed butterflies in the tribe Nymphalini. It has a near-global distribution and includes conspicuous species such as the red admirals (e.g., red admiral, Indian red admiral, New Zealand red admiral), the Kamehameha, and the painted ladies of the ''Cynthia'' group (formerly a subgenus): Painted lady, American painted lady, West Coast lady, Australian painted lady, etc. For African admirals, see genus ''Antanartia''. Recently, several members traditionally considered to be in the genus ''Antanartia'' have been determined to belong within the genus ''Vanessa''. The name of the genus may have been taken from the character Vanessa in Jonathan Swift's poem "Cadenus and Vanessa," which is the source of the woman's name Vanessa. In the poem Vanessa is called a "nymph" eleven times, and the genus is closely related to the previously-named genus Nymphalis. Though the name has been suggested to be a variant of "Phanessa", from the name of an Ancient Gre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sápmi (area)
(, smj, Sábme / Sámeednam, sma, Saepmie, sju, Sábmie, , , sjd, Са̄мь е̄ммьне, Saam' jiemm'n'e) is the cultural region traditionally inhabited by the Sámi people. Sápmi is in Northern and Eastern Europe and includes the northern parts of Fennoscandia, also known as the "Cap of the North". The region stretches over four countries: Norway, Sweden, Finland, and Russia. On the north it is bounded by the Barents Sea, on the west by the Norwegian Sea, and on the east by the White Sea."Lapland." Encyclopædia Britannica. ''Encyclopædia Britannica Online. Encyclopædia Britannica'', 2009. Web. 24 November 2009 http://search.eb.com/eb/article-9047170. The area is historically referred to as Lapland () in English, although the term "Lapp" for its inhabitants is now considered pejorative.; ; Norwegian Sápmi was historically called ''Finnmǫrk'', a name used for the former county Finnmark, now Troms og Finnmark. Sápmi refers to the areas where the Sámi people h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Syria
Syria ( ar, سُورِيَا or سُورِيَة, translit=Sūriyā), officially the Syrian Arab Republic ( ar, الجمهورية العربية السورية, al-Jumhūrīyah al-ʻArabīyah as-Sūrīyah), is a Western Asian country located in the Eastern Mediterranean and the Levant. It is a unitary republic that consists of 14 governorates (subdivisions), and is bordered by the Mediterranean Sea to the west, Turkey to the north, Iraq to the east and southeast, Jordan to the south, and Israel and Lebanon to the southwest. Cyprus lies to the west across the Mediterranean Sea. A country of fertile plains, high mountains, and deserts, Syria is home to diverse ethnic and religious groups, including the majority Syrian Arabs, Kurds, Turkmens, Assyrians, Armenians, Circassians, Albanians, and Greeks. Religious groups include Muslims, Christians, Alawites, Druze, and Yazidis. The capital and largest city of Syria is Damascus. Arabs are the largest ethnic group, and Mu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drosophila Melanogaster
''Drosophila melanogaster'' is a species of fly (the taxonomic order Diptera) in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the "vinegar fly" or "pomace fly". Starting with Charles W. Woodworth's 1901 proposal of the use of this species as a model organism, ''D. melanogaster'' continues to be widely used for biological research in genetics, physiology, microbial pathogenesis, and life history evolution. As of 2017, five Nobel Prizes have been awarded to drosophilists for their work using the insect. ''D. melanogaster'' is typically used in research owing to its rapid life cycle, relatively simple genetics with only four pairs of chromosomes, and large number of offspring per generation. It was originally an African species, with all non-African lineages having a common origin. Its geographic range includes all continents, including islands. ''D. melanogaster'' is a common pest in homes, restaurants, and othe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thomas Hunt Morgan
Thomas Hunt Morgan (September 25, 1866 – December 4, 1945) was an American evolutionary biologist, geneticist, embryologist, and science author who won the Nobel Prize in Physiology or Medicine in 1933 for discoveries elucidating the role that the chromosome plays in heredity. Morgan received his Ph.D. from Johns Hopkins University in zoology in 1890 and researched embryology during his tenure at Bryn Mawr. Following the rediscovery of Mendelian inheritance in 1900, Morgan began to study the genetic characteristics of the fruit fly ''Drosophila melanogaster''. In his famous Fly Room at Columbia University's Schermerhorn Hall, Morgan demonstrated that genes are carried on chromosomes and are the mechanical basis of heredity. These discoveries formed the basis of the modern science of genetics. During his distinguished career, Morgan wrote 22 books and 370 scientific papers. As a result of his work, ''Drosophila'' became a major model organism in contemporary genetics. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
