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Sonic Hedgehog (gene)
Sonic hedgehog protein (SHH) is encoded for by the ''SHH'' gene. The protein is named after the character ''Sonic the Hedgehog''. This signaling molecule is key in regulating embryonic morphogenesis in all animals. SHH controls organogenesis and the organization of the central nervous system, limbs, digits and many other parts of the body. Sonic hedgehog is a morphogen that patterns the developing embryo using a concentration gradient characterized by the French flag model. This model has a non-uniform distribution of SHH molecules which governs different cell fates according to concentration. Mutations in this gene can cause holoprosencephaly, a failure of splitting in the cerebral hemispheres, as demonstrated in an experiment using SHH knock-out mice in which the forebrain midline failed to develop and instead only a single fused telencephalic vesicle resulted. Sonic hedgehog still plays a role in differentiation, proliferation, and maintenance of adult tissues. Abnormal activ ... [...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 g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eric Wieschaus
Eric Francis Wieschaus (born June 8, 1947 in South Bend, Indiana) is an American evolutionary developmental biologist and 1995 Nobel Prize-winner. Early life Born in South Bend, Indiana, he attended John Carroll Catholic High School in Birmingham, Alabama before attending the University of Notre Dame for his undergraduate studies (B.S., biology), and Yale University (Ph.D., biology) for his graduate work. Scientific career In 1978, he moved to his first independent job, at the European Molecular Biology Laboratory in Heidelberg, Germany and moved from Heidelberg to Princeton University in the United States in 1981. Much of his research has focused on embryogenesis in the fruit fly ''Drosophila melanogaster'', specifically in the patterning that occurs in the early ''Drosophila'' embryo. Most of the gene products used by the embryo at these stages are already present in the unfertilized egg and were produced by maternal transcription during oogenesis. A small number of g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zebra Danio
The zebrafish (''Danio rerio'') is a freshwater fish belonging to the minnow family (Cyprinidae) of the order Cypriniformes. Native to South Asia, it is a popular aquarium fish, frequently sold under the trade name zebra danio (and thus often called a "tropical fish" although both tropical and subtropical). It is also found in private ponds. The zebrafish is an important and widely used vertebrate model organism in scientific research, for example in drug development, in particular pre-clinical development. It is also notable for its regenerative abilities, and has been modified by researchers to produce many transgenic strains. Taxonomy The zebrafish is a derived member of the genus ''Brachydanio'', of the family Cyprinidae. It has a sister-group relationship with '' Danio aesculapii''. Zebrafish are also closely related to the genus '' Devario'', as demonstrated by a phylogenetic tree of close species. Distribution Range The zebrafish is native to fresh water ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sonic The Hedgehog (1991 Video Game)
is a 1991 platform game developed by Sonic Team and published by Sega for the Sega Genesis. The first game in the ''Sonic the Hedgehog'' franchise, it was released in North America on June 23 and in PAL regions and Japan the following month. Players control Sonic the Hedgehog, who can run at supersonic speeds; Sonic sets out on a quest to defeat Dr. Robotnik, a scientist who has imprisoned animals in robots and seeks the powerful Chaos Emeralds. The gameplay involves collecting rings as a form of health, and a simple control scheme, with jumping and attacking controlled by a single button. Development began in 1990 when Sega ordered its developers to create a game featuring a mascot for the company. The developers decided on a blue hedgehog and named themselves Sonic Team to match their character. ''Sonic the Hedgehog'', designed for fast gameplay, was influenced by games by ''Super Mario'' series creator Shigeru Miyamoto. It uses a novel technique that allows Sonic's sprite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indian Hedgehog (protein)
Indian hedgehog homolog (Drosophila), also known as IHH, is a protein which in humans is encoded by the ''IHH'' gene. This cell signaling protein is in the hedgehog signaling pathway. The several mammalian variants of the ''Drosophila'' hedgehog gene ( which was the first named) have been named after the various species of hedgehog; the Indian hedgehog is honored by this one. The gene is not specific to Indian hedgehogs. Function The Indian hedgehog protein is one of three proteins in the mammalian hedgehog family, the others being desert hedgehog (DHH) and sonic hedgehog (SHH). It is involved in chondrocyte differentiation, proliferation and maturation especially during endochondral ossification. It regulates its effects by feedback control of parathyroid hormone-related peptide (PTHrP Parathyroid hormone-related protein (PTHrP) is a proteinaceous hormone and a member of the parathyroid hormone family secreted by mesenchymal stem cells. It is occasionally secreted by canc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desert Hedgehog (protein)
Desert hedgehog, also Desert hedgehog homolog or Dhh, is a protein encoded by the DHH gene, and is a member of the hedgehog signaling pathway. The human homolog (DHH) is on chromosome band 12q13.1. The protein encoded by this gene is involved in cell signaling. The several mammalian variants of the ''Drosophila'' hedgehog gene ( which was the first named) have been named after the various species of hedgehog; the desert hedgehog is honored by this one. The gene is not specific to desert hedgehogs. Function This gene encodes a member of the hedgehog family. The hedgehog gene family encodes signaling molecules that play an important role in regulating morphogenesis. This protein is predicted to be made as a precursor that is autocatalytically cleaved; the N-terminal portion is soluble and contains the signalling activity while the C-terminal portion is involved in precursor processing. More importantly, the C-terminal product covalently attaches a cholesterol moiety to the N-t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homology (biology)
In biology, homology is similarity due to shared ancestry between a pair of structures or genes in different taxa. A common example of homologous structures is the forelimbs of vertebrates, where the wings of bats and birds, the arms of primates, the front flippers of whales and the forelegs of four-legged vertebrates like dogs and crocodiles are all derived from the same ancestral tetrapod structure. Evolutionary biology explains homologous structures adapted to different purposes as the result of descent with modification from a common ancestor. The term was first applied to biology in a non-evolutionary context by the anatomist Richard Owen in 1843. Homology was later explained by Charles Darwin's theory of evolution in 1859, but had been observed before this, from Aristotle onwards, and it was explicitly analysed by Pierre Belon in 1555. In developmental biology, organs that developed in the embryo in the same manner and from similar origins, such as from matc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clifford Tabin
Clifford James Tabin (born 1954) is chairman of the Department of Genetics at Harvard Medical School. Education Tabin was educated at the University of Chicago where he was awarded a BS in physics in 1976. He went on to graduate school at Massachusetts Institute of Technology and was awarded a PhD in 1984 for work on the regulation of gene expression in the Ras subfamily of oncogenes supervised by Robert Weinberg based in the MIT Department of Biology. In Weinberg's lab, Tabin constructed murine leukemia virus, the first recombinant retrovirus that could be used as a eukaryotic vector. Career Following his PhD, Tabin did postdoctoral research with Douglas A. Melton at Harvard University, then moved to Massachusetts General Hospital where he worked on the molecular biology of limb development. He was appointed to the faculty in the Department of Genetics at Harvard Medical School in 1989, and promoted to full professor in 1997 and chairman of the department in January 2007.< ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philip Ingham
Philip William Ingham FRS, FMedSci, Hon. FRCP (born 19 March 1955 Liverpool) is a British geneticist, currently the Toh Kian Chui Distinguished Professor at the Lee Kong Chian School of Medicine, a partnership between Nanyang Technological University, Singapore and Imperial College, London. Previously, he was the inaugural Director of the Living Systems Institute at the University of Exeter, UK and prior to that was Vice Dean, Research at the Lee Kong Chian School of Medicine. Career Ingham was educated at Merchant Taylors' School, Crosby near Liverpool and then at Queens' College in the University of Cambridge where after initially reading Philosophy and Theology he graduated in Genetics. He gained his Doctorate of Philosophy from the University of Sussex under the supervision of J Robert S Whittle before moving to the Laboratoire de Génétique Moleculaire des Eukaryotes in Strasbourg, France, as a Royal Society European Exchange Programme fellow. He returned to the UK in 19 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hedgehog
A hedgehog is a spiny mammal of the subfamily Erinaceinae, in the eulipotyphlan family Erinaceidae. There are seventeen species of hedgehog in five genera found throughout parts of Europe, Asia, and Africa, and in New Zealand by introduction. There are no hedgehogs native to Australia and no living species native to the Americas. However, the extinct genus '' Amphechinus'' was once present in North America. Hedgehogs share distant ancestry with shrews (family Soricidae), with gymnures possibly being the intermediate link, and they have changed little over the last fifteen million years. Like many of the first mammals, they have adapted to a nocturnal way of life. Their spiny protection resembles that of porcupines, which are rodents, and echidnas, a type of monotreme. Etymology The name ''hedgehog'' came into use around the year 1450, derived from the Middle English ''heyghoge'', from ''heyg'', ''hegge'' ("hedge"), because it frequents hedgerows, and ''hoge'', ''hogg ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Segmentation (biology)
Segmentation in biology is the division of some animal and plant body plans into a series of repetitive segments. This article focuses on the segmentation of animal body plans, specifically using the examples of the taxa Arthropoda, Chordata, and Annelida. These three groups form segments by using a "growth zone" to direct and define the segments. While all three have a generally segmented body plan and use a growth zone, they use different mechanisms for generating this patterning. Even within these groups, different organisms have different mechanisms for segmenting the body. Segmentation of the body plan is important for allowing free movement and development of certain body parts. It also allows for regeneration in specific individuals. Definition Segmentation is a difficult process to satisfactorily define. Many taxa (for example the molluscs) have some form of serial repetition in their units but are not conventionally thought of as segmented. Segmented animals are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
