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Sonic Hedgehog
Sonic hedgehog protein (SHH) is a major signaling molecule of embryonic development in humans and animals, encoded by the ''SHH'' gene. 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. Abno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signaling Molecule
In biology, cell signaling (cell signalling in British English) is the Biological process, process by which a Cell (biology), cell interacts with itself, other cells, and the environment. Cell signaling is a fundamental property of all Cell (biology), cellular life in both prokaryotes and eukaryotes. Typically, the signaling process involves three components: the signal, the receptor, and the effector. In biology, signals are mostly chemical in nature, but can also be physical cues such as pressure, Membrane potential, voltage, temperature, or light. Chemical signals are molecules with the ability to bind and activate a specific Receptor (biochemistry), receptor. These molecules, also referred to as Ligand (biochemistry), ligands, are chemically diverse, including ions (e.g. Na+, K+, Ca2+, etc.), lipids (e.g. steroid, prostaglandin), peptides (e.g. insulin, ACTH), carbohydrates, glycosylated proteins (proteoglycans), nucleic acids, etc. Peptide and lipid ligands are particularly ... [...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 biology, evolutionary developmental biologist and 1995 Nobel Prize-winner. Early life Born in South Bend, Indiana, he attended John Carroll Catholic High School (Birmingham, Alabama), 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 Drosophila embryogenesis, 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 p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sonic The Hedgehog (1991 Video Game)
is a 1991 platform game developed and published by Sega for the Sega Genesis. It was released in PAL regions on June 21, North America two days later on June 23 and in 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 chose a blue hedgehog designed by Naoto Ohshima after he won an internal character design contest, and named themselves Sonic Team to match their character. It uses a novel technique that allows Sonic's sprite to roll along curved scenery which was based on a concept by Oshima from 1989. ''Sonic the Hedgeho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sonic The Hedgehog (character)
is a Character (arts), character created by the Japanese game designers Yuji Naka and Naoto Ohshima. He is the star of the ''Sonic the Hedgehog'' franchise and the mascot of the Japanese video game company Sega. Sonic is an anthropomorphism, anthropomorphic blue hedgehog who can run at supersonic speed. He races through Level (video games), levels, collecting Rings (Sonic the Hedgehog), rings and avoiding obstacles, as he seeks to defeat his archenemy, Doctor Eggman. He is accompanied by Characters of Sonic the Hedgehog, supporting characters, such as his best friend and sidekick Miles "Tails" Prower, romantic interest Amy Rose, and friendly rival Knuckles the Echidna. Sonic made a cameo appearance in the arcade game ''Rad Mobile'' (1990) before starring in ''Sonic the Hedgehog (1991 video game), Sonic the Hedgehog'', a platform game for the Sega Genesis, in 1991. Sega sought a mascot to compete with Nintendo's Mario, and Ohshima designed Sonic based on a prototype programme ... [...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 Endochondral ossification is one of the two essential pathways by which bone tissue is produced during fetal development and bone healing, bone repair of the mammalian skeleton, skeletal system, the other pathway being intramembranous ossificatio .... It regulates its effects by ... [...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. The Desert Hedgehog gene has been identified in both humans and mouse models. 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 importan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homology (biology)
In biology, homology is similarity in anatomical structures or genes between organisms of different taxa due to shared ancestry, ''regardless'' of current functional differences. Evolutionary biology explains homologous structures as retained heredity from a common descent, common ancestor after having been subjected to adaptation (biology), adaptive modifications for different purposes as the result of natural selection. 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's biology onwards, and it was explicitly analysed by Pierre Belon in 1555. A common example of homologous structures is the forelimbs of vertebrates, where the bat wing development, wings of bats and origin of avian flight, birds, the arms of primates, the front flipper (anatomy), flippers of whales, and the forelegs of quadrupedalis ... [...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 (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, 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 1982, joining the Imperial Cancer Research Fund ... [...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 17 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 15 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 , from , , because it frequents hedgerows, and , , from its piglike snout. Other names that are used are ''urchin' ... [...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 (physical form and structure), its developmental processes, its biochemical and physiological properties, and its behavior. An organism's phenotype results from two basic factors: the expression of an organism's genetic code (its genotype) and the influence of environmental factors. Both factors may interact, further affecting the 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 again in his 1982 book '' The Extended Phenotype'' suggested that one can regard bird nests and other built structures such as caddisfly larva cases and beaver dams ... [...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 linear series of repetitive segments that may or may not be interconnected to each other. 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 conventi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
