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82-571: The original zebrafish (or zebra danio, Danio rerio ) is a native of rivers in India and Bangladesh . It measures three centimeters long and has gold and dark blue stripes. In 1999, Dr. Zhiyuan Gong and his colleagues at the National University of Singapore were working with a gene that encodes the green fluorescent protein (GFP), originally extracted from a jellyfish , that naturally produced bright green fluorescence . They inserted

164-432: A homozygous embryo. The zebrafish embryos are transparent and they develop outside of the uterus, which allows scientists to study the details of development starting from fertilization and continuing throughout development. The zebrafish is also demonstrably similar to mammalian models and humans in toxicity testing, and exhibits a diurnal sleep cycle with similarities to mammalian sleep behavior. However, zebrafish are not

246-480: A medaka (rice fish) with a fluorescent green color, which, like the zebrafish, is a model organism used in biology. The scientists from NUS and businessmen Alan Blake and Richard Crockett from Yorktown Technologies, L.P., a company in Austin, Texas , met and a deal was signed whereby Yorktown obtained the worldwide rights to market the fluorescent zebrafish, which Yorktown subsequently branded as "GloFish". At around

328-605: A solute carrier that appeared to be required for melanin production, and confirmed its function with a Morpholino knockdown. The orthologous gene was then characterized in humans and a one base pair difference was found to strongly segregate fair-skinned Europeans and dark-skinned Africans. Zebrafish with the nacre mutation have since been bred with fish with a roy orbison (roy) mutation to make Casper strain fish that have no melanophores or iridophores, and are transparent into adulthood. These fish are characterized by uniformly pigmented eyes and translucent skin. Transgenesis

410-413: A daily basis. Females are able to spawn at intervals of two to three days, laying hundreds of eggs in each clutch . Upon release, embryonic development begins; in absence of sperm, growth stops after the first few cell divisions. Fertilized eggs almost immediately become transparent, a characteristic that makes D. rerio a convenient research model species . Sex determination of common laboratory strains

492-497: A dedicated online database of genetic, genomic, and developmental information, the Zebrafish Information Network (ZFIN). The Zebrafish International Resource Center (ZIRC) is a genetic resource repository with 29,250 alleles available for distribution to the research community. D. rerio is also one of the few fish species to have been sent into space . Research with D. rerio has yielded advances in

574-649: A different brand name. GloFish were introduced to the United States market in late 2003 by Yorktown Technologies, after two years of research. The governmental environmental risk assessment was made by the U.S. Food and Drug Administration (FDA), which has jurisdiction over all genetically modified (GM) animals, including fluorescent zebra fish, since they consider the inserted gene to be a drug. The FDA determined in December 2003: Because tropical aquarium fish are not used for food purposes, they pose no threat to

656-407: A group, males will mate with whichever females they can find. What attracts females is not currently understood. The presence of plants, even plastic plants, also apparently encourages spawning. Exposure to environmentally relevant concentrations of diisononyl phthalate (DINP), commonly used in a large variety of plastic items, disrupt the endocannabinoid system and thereby affect reproduction in

738-597: A laboratory animal was pioneered by the American molecular biologist George Streisinger and his colleagues at the University of Oregon in the 1970s and 1980s; Streisinger's zebrafish clones were among the earliest successful vertebrate clones created. Its importance has been consolidated by successful large-scale forward genetic screens (commonly referred to as the Tübingen/Boston screens). The fish has

820-460: A new strain of zebrafish, named Casper, whose adult bodies had transparent skin. This allows for detailed visualization of cellular activity, circulation, metastasis and many other phenomena. In 2019 researchers published a crossing of a prkdc and a IL2rga strain that produced transparent, immunodeficient offspring, lacking natural killer cells as well as B - and T-cells . This strain can be adapted to 37 °C (99 °F) warm water and

902-592: A number of commercially available global platforms exist for analysis of both gene expression by microarrays and promoter regulation using ChIP-on-chip . The Wellcome Trust Sanger Institute started the zebrafish genome sequencing project in 2001, and the full genome sequence of the Tuebingen reference strain is publicly available at the National Center for Biotechnology Information (NCBI)'s Zebrafish Genome Page . The zebrafish reference genome sequence

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984-667: A regulation that restricts genetically modified fish. The regulation was implemented before the marketing of GloFish, largely due to concern about a fast-growing biotech salmon. The regulations were lifted in 2015 due to a growing body of evidence and the findings of the Food and Drug Administration and the Florida Department of Agriculture and Consumer Services . GloFish are now legal in California for importation and commercial sale. The import, sale and possession of these fish

1066-460: A sex-specific manner. Zebrafish feeding practices vary significantly across different developmental stages, reflecting their changing nutritional needs. For newly hatched larvae, which begin feeding at approximately 5 days post-fertilization (dpf), small live prey such as Paramecium or rotifers are commonly used until they reach 9–15 dpf. This early diet is crucial for their growth and survival, as these small organisms provide essential nutrients. As

1148-515: A significant advantage over GloFish when it came to mating. According to the mating trials that were analyzed in the study, wild-type males sired twice as much as the genetically modified fish due to their more aggressive nature. However, in Owen et al. 2012 by the same group, female zebrafish preferred the GloFish rather than wild-type males. Zebrafish The zebrafish ( Danio rerio )

1230-490: A sliding bottom insert, which reduces the depth of the pool to simulate the shore of a river. Zebrafish spawn best in the morning due to their Circadian rhythms . Researchers have been able to collect 10,000 embryos in 10 minutes using this method. In particular, one pair of adult fish is capable of laying 200–300 eggs in one morning in approximately 5 to 10 at time. Male zebrafish are furthermore known to respond to more pronounced markings on females, i.e., "good stripes", but in

1312-412: A specialised protein , known as fibroblast growth factor , to ensure their spinal cords heal without glial scarring after injury. In addition, hair cells of the posterior lateral line have also been found to regenerate following damage or developmental disruption. Study of gene expression during regeneration has allowed for the identification of several important signaling pathways involved in

1394-437: A study was published about zebrafishes' capacity for episodic memory . The individuals showed a capacity to remember context with respect to objects, locations and occasions (what, when, where). Episodic memory is a capacity of explicit memory systems, typically associated with conscious experience . The Mauthner cells integrate a wide array of sensory stimuli to produce the escape reflex . Those stimuli are found to include

1476-512: A universally ideal research model; there are a number of disadvantages to their scientific use, such as the absence of a standard diet and the presence of small but important differences between zebrafish and mammals in the roles of some genes related to human disorders. Zebrafish have the ability to regenerate their heart and lateral line hair cells during their larval stages. The cardiac regenerative process likely involves signaling pathways such as Notch and Wnt ; hemodynamic changes in

1558-411: A variety of different DNA repair pathways are expressed during development. Zebrafish have, in recent years, proven to be a useful model for assessing environmental pollutants that might cause DNA damage. Black tetra The black tetra ( Gymnocorymbus ternetzi ), also known as the black skirt tetra , petticoat tetra , high-fin black skirt tetra , black widow tetra and blackamoor ,

1640-422: Is 16,596 base pairs. This is within 100 base pairs of other related species of fish, and it is notably only 18 pairs longer than the goldfish ( Carassius auratus ) and 21 longer than the carp ( Cyprinus carpio ). Its gene order and content are identical to the common vertebrate form of mitochondrial DNA. It contains 13 protein -coding genes and a noncoding control region containing the origin of replication for

1722-562: 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 it is both tropical and subtropical ). The zebrafish is an important and widely used vertebrate model organism in scientific research, particularly developmental biology , but also gene function, oncology , teratology , and drug development , in particular pre-clinical development . It

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1804-549: Is a freshwater fish of the characin family ( Characidae ). It is native to the Paraguay River basin of south-central Brazil (mainly Pantanal region), Paraguay and northeast Argentina , but there are also populations in the upper Paraná and Paraíba do Sul Rivers that likely were introduced . It was formerly reported from the Guapore River , but this population is part of G. flaviolimai , which

1886-493: Is a popular approach to study the function of genes in zebrafish. Construction of transgenic zebrafish is rather easy by a method using the Tol2 transposon system. Tol2 element which encodes a gene for a fully functional transposase capable of catalyzing transposition in the zebrafish germ lineage. Tol2 is the only natural DNA transposable element in vertebrates from which an autonomous member has been identified. Examples include

1968-508: Is a spotted colour morph of the zebrafish which arose due to a pigment mutation. Xanthistic forms of both the zebra and leopard pattern, along with long-finned strains, have been obtained via selective breeding programs for the aquarium trade. Various transgenic and mutant strains of zebrafish were stored at the China Zebrafish Resource Center (CZRC), a non-profit organization, which was jointly supported by

2050-405: Is able to integrate into most cells of the embryo. A known problem with gene knockdowns is that, because the genome underwent a duplication after the divergence of ray-finned fishes and lobe-finned fishes , it is not always easy to silence the activity of one of the two gene paralogs reliably due to complementation by the other paralog. Despite the complications of the zebrafish genome ,

2132-428: Is also notable for its regenerative abilities, and has been modified by researchers to produce many transgenic strains. 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. The zebrafish

2214-658: Is annotated as part of the Ensembl project , and is maintained by the Genome Reference Consortium . In 2009, researchers at the Institute of Genomics and Integrative Biology in Delhi, India, announced the sequencing of the genome of a wild zebrafish strain, containing an estimated 1.7 billion genetic letters. The genome of the wild zebrafish was sequenced at 39-fold coverage. Comparative analysis with

2296-498: Is found throughout the Madeira River basin and was described in 2015. The black tetra is often kept in aquariums. Growing up to 7.5 cm (3.0 in) in length, the black tetra has a roughly tetragonal body shape and is greyish in colour, fading from near black at the tail to light at the nose. Two prominent, black, vertical bars appear just posterior to the gills. It is easily distinguished from all of its congeners by

2378-546: Is linked to male infertility. The researchers cloned oestrogen-sensitive genes and injected them into the fertile eggs of zebrafish. The modified fish turned green if placed into water that was polluted by oestrogen. In 2015, researchers at Brown University discovered that 10% of zebrafish genes do not need to rely on the U2AF2 protein to initiate RNA splicing . These genes have the DNA base pairs AC and TG as repeated sequences at

2460-566: Is more local, with scattered records from the Western and Eastern Ghats regions. It has frequently been said to occur in Myanmar (Burma), but this is entirely based on pre-1930 records and likely refers to close relatives only described later, notably Danio kyathit . Likewise, old records from Sri Lanka are highly questionable and remain unconfirmed. Zebrafish have been introduced to California, Connecticut, Florida and New Mexico in

2542-818: Is native to freshwater habitats in South Asia where it is found in India, Pakistan, Bangladesh, Nepal and Bhutan. The northern limit is in the South Himalayas , ranging from the Sutlej river basin in the Pakistan–India border region to the state of Arunachal Pradesh in northeast India. Its range is concentrated in the Ganges and Brahmaputra River basins, and the species was first described from Kosi River (lower Ganges basin) of India. Its range further south

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2624-587: Is not permitted within the European Union. On November 9, 2006, however, the Netherlands’ Ministry of Housing, Spatial Planning and the Environment (VROM) found 1,400 fluorescent fish, which were sold in various aquarium shops. In January 2009, the U.S. Food & Drug Administration formalized their recommendations for genetically engineered animals. These non-binding recommendations describe

2706-407: Is to reduce gene expression or modify splicing using Morpholino antisense technology. Morpholino oligonucleotides (MO) are stable, synthetic macromolecules that contain the same bases as DNA or RNA; by binding to complementary RNA sequences, they can reduce the expression of specific genes or block other processes from occurring on RNA. MO can be injected into one cell of an embryo after

2788-407: Is usually some vegetation, either submerged or overhanging from the banks, and the bottom is sandy, muddy or silty, often mixed with pebbles or gravel. In surveys of zebrafish locations throughout much of its Bangladeshi and Indian distribution, the water had a near-neutral to somewhat basic pH and mostly ranged from 16.5 to 34 °C (61.7–93.2 °F) in temperature. One unusually cold site

2870-414: Is very rapid, and its embryos are relatively large, robust, and transparent, and able to develop outside their mother. Furthermore, well-characterized mutant strains are readily available. Other advantages include the species' nearly constant size during early development, which enables simple staining techniques to be used, and the fact that its two-celled embryo can be fused into a single cell to create

2952-586: The Carp (including Grass Carp, Ctenopharyngodon idella ) and Milkfish ( Chanos chanos ) which are quite close, both being in the Cyprinidae . However it should also be noted that Danio consistently proves to be a useful model for mammals in many cases and there is dramatically more genetic distance between them than between Danio and any farmed fish. In a glucocorticoid receptor -defective mutant with reduced exploratory behavior , fluoxetine rescued

3034-554: The Center for Food Safety . They were concerned that approval of the GloFish based only on a Food and Drug Administration risk assessment would create a precedent of inadequate scrutiny of biotech animals in general. The group filed a lawsuit in US Federal District Court to block the sale of the GloFish. The lawsuit sought a court order stating that the sale of transgenic fish is subject to federal regulation beyond

3116-634: The Ministry of Science and Technology of China and the Chinese Academy of Sciences . The Zebrafish Information Network ( ZFIN ) provides up-to-date information about current known wild-type (WT) strains of D. rerio , some of which are listed below. Hybrids between different Danio species may be fertile: for example, between D. rerio and D. nigrofasciatus . D. rerio is a common and useful scientific model organism for studies of vertebrate development and gene function. Its use as

3198-401: The anal fin origin. The zebrafish can reach up to 4–5 cm (1.6–2.0 in) in length, although they typically are 1.8–3.7 cm (0.7–1.5 in) in the wild with some variations depending on location. Its lifespan in captivity is around two to three years, although in ideal conditions, this may be extended to over five years. In the wild it is typically an annual species. In 2015,

3280-443: The black tetra . This was followed by a green version of a tiger barb . In 2013, Yorktown Technologies introduced orange, pink, and purple Tetras, which made Tetras the first GloFish to be available in pink. This was followed in 2014 by the release of red and blue Tetras. The colors are trademarked as "Starfire Red", "Moonrise Pink", "Sunburst Orange", "Electric Green", "Cosmic Blue", and "Galactic Purple". Other fish released include

3362-469: The lateral line signals by McHenry et al. 2009 and visual signals consistent with looming objects by Temizer et al. 2015, Dunn et al. 2016, and Yao et al. 2016. The approximate generation time for Danio rerio is three months. A male must be present for ovulation and spawning to occur. Zebrafish are asynchronous spawners and under optimal conditions (such as food availability and favorable water parameters) can spawn successfully frequently, even on

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3444-432: The replication crisis in biomedical research. Genetic differences in wild-type lines among populations maintained at different research institutions have been demonstrated using both Single-nucleotide polymorphisms and microsatellite analysis. Due to their fast and short life cycles and relatively large clutch sizes, D. rerio or zebrafish are a useful model for genetic studies. A common reverse genetics technique

3526-410: The 32-cell stage, reducing gene expression in only cells descended from that cell. However, cells in the early embryo (less than 32 cells) are permeable to large molecules, allowing diffusion between cells. Guidelines for using Morpholinos in zebrafish describe appropriate control strategies. Morpholinos are commonly microinjected in 500pL directly into 1–2 cell stage zebrafish embryos. The morpholino

3608-724: The FDA's charter, and as such should not be sold without more extensive approvals. In the opinion of Joseph Mendelson, the Center for Food Safety's legal director: It's clear this sets a precedent for genetically engineered animals. It opens the dams to a whole host of nonfood genetically engineered organisms. That's unacceptable to us and runs counter to things the National Academy of Sciences and other scientific review boards have said, particularly when it comes to mobile GM organisms like fish and insects. The Center for Food Safety's suit

3690-402: The GloFish shark, available in orange, green, and purple. Though these fish are not scientifically related to sharks, they are based on the albino rainbow shark. In February 2020, green GloFish bettas also known as Globettas were released, with three different variations. These variations include female, (young) male, and premium (adult) male. Despite the speculation of aquarium enthusiasts that

3772-550: The National University of Singapore filed a patent application on this work. Shortly thereafter, his team developed a line of red fluorescent zebra fish by adding a gene from a sea coral , and orange-yellow fluorescent zebra fish, by adding a variant of the jellyfish gene. Later, a team of researchers at the National Taiwan University , headed by Professor Huai-Jen Tsai, succeeded in creating

3854-550: The United States, presumably by deliberate release by aquarists or by escape from fish farms . The New Mexico population had been extirpated by 2003 and it is unclear if the others survive, as the last published records were decades ago. Elsewhere the species has been introduced to Colombia and Malaysia. Zebrafish typically inhabit moderately flowing to stagnant clear water of quite shallow depth in streams, canals, ditches, oxbow lakes , ponds and rice paddies . There

3936-399: The absence of an immune system makes the use of patient derived xenografts possible. In January 2013, Japanese scientists genetically modified a transparent zebrafish specimen to produce a visible glow during periods of intense brain activity. In January 2007, Chinese researchers at Fudan University genetically modified zebrafish to detect oestrogen pollution in lakes and rivers, which

4018-434: The artificial interaction produced between LEF1 and Catenin beta-1 /β-catenin/ CTNNB1 . Dorsky et al. 2002 investigated the developmental role of Wnt by transgenically expressing a Lef1/β-catenin reporter. There are well-established protocols for editing zebrafish genes using CRISPR-Cas9 and this tool has been used to generate genetically modified models. In 2008, researchers at Boston Children's Hospital developed

4100-783: The damaged heart are sensed by ventricular endothelial cells and their associated cardiac cilia by way of the mechanosensitive ion channel TRPV4 , subsequently facilitating the Notch signaling pathway via KLF2 and activating various downstream effectors such as BMP-2 and HER2/neu . In 2011, the British Heart Foundation ran an advertising campaign publicising its intention to study the applicability of this ability to humans, stating that it aimed to raise £50 million in research funding. Zebrafish have also been found to regenerate photoreceptor cells and retinal neurons following injury, which has been shown to be mediated by

4182-424: The dedifferentiation and proliferation of Müller glia . Researchers frequently amputate the dorsal and ventral tail fins and analyze their regrowth to test for mutations. It has been found that histone demethylation occurs at the site of the amputation, switching the zebrafish's cells to an "active", regenerative, stem cell-like state. In 2012, Australian scientists published a study revealing that zebrafish use

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4264-492: The detrimental effects of inbreeding depression . Inbreeding depression is predominantly caused by the homozygous expression of recessive deleterious alleles. For zebrafish, inbreeding depression might be expected to be more severe in stressful environments, including those caused by anthropogenic pollution . Exposure of zebrafish to environmental stress induced by the chemical clotrimazole, an imidazole fungicide used in agriculture and in veterinary and human medicine, amplified

4346-448: The effects of inbreeding on key reproductive traits. Embryo viability was significantly reduced in inbred exposed fish and there was a tendency for inbred males to sire fewer offspring. Zebrafish are common models for research into fish farming , including pathogens and parasites causing yield loss or spreading to adjacent wild populations. This usefulness is less than it might be due to Danio ' s taxonomic distance from

4428-591: The eggs of the fluorescent fish were pressure treated to make them infertile, it has been found some GloFish are indeed fertile and will reproduce in a captive environment. However, the GloFish Fluorescent Fish License states "Intentional breeding and/or any sale, barter, or trade, of any offspring of GloFish fluorescent ornamental fish is strictly prohibited.". Sale or possession of GloFish was made illegal in California in 2003 due to

4510-457: The ends of each intron . On the 3'ss (3' splicing site), the base pairs adenine and cytosine alternate and repeat, and on the 5'ss (5' splicing site), their complements thymine and guanine alternate and repeat as well. They found that there was less reliance on U2AF2 protein than in humans, in which the protein is required for the splicing process to occur. The pattern of repeating base pairs around introns that alters RNA secondary structure

4592-503: The fields of developmental biology , oncology , toxicology , reproductive studies, teratology , genetics , neurobiology , environmental sciences , stem cell research, regenerative medicine , muscular dystrophies and evolutionary theory . As a model biological system, the zebrafish possesses numerous advantages for scientists. Its genome has been fully sequenced , and it has well-understood, easily observable and testable developmental behaviors. Its embryonic development

4674-409: The first species to be sold as GloFish (fluorescent colored fish). In late 2003, transgenic zebrafish that express green , red, and yellow fluorescent proteins became commercially available in the United States. The fluorescent strains are trade-named GloFish ; other cultivated varieties include "golden", "sandy", "longfin" and "leopard". The leopard danio, previously known as Danio frankei ,

4756-420: The food supply. There is no evidence that these genetically engineered zebra danio fish pose any more threat to the environment than their unmodified counterparts which have long been widely sold in the United States. In the absence of a clear risk to the public health, the FDA finds no reason to regulate these particular fish. Marketing of the fish was met by protests from a non-governmental organization called

4838-418: The gene into a zebrafish embryo, allowing it to integrate into the zebrafish's genome , which caused the fish to be brightly fluorescent under both natural white light and ultraviolet light. Their goal was to develop a fish that could detect pollution by selectively fluorescing in the presence of environmental toxins . The development of the constantly fluorescing fish was the first step in this process, and

4920-634: The heavy strand. In between a grouping of five tRNA genes, a sequence resembling vertebrate origin of light strand replication is found. It is difficult to draw evolutionary conclusions because it is difficult to determine whether base pair changes have adaptive significance via comparisons with other vertebrates' nucleotide sequences. T-boxes and homeoboxes are vital in Danio similarly to other vertebrates. The Bruce et al. team are known for this area, and in Bruce et al. 2003 & Bruce et al. 2005 uncover

5002-411: The larvae develop, from 15 dpf onwards, they are typically transitioned to a diet that includes brine shrimp nauplii and dry feeds, which are more nutritionally balanced and easier to manage in laboratory settings. For larvae aged 25 dpf, feeding rates can range from 50% to 300% of their body weight (BW) per day, depending on their size and growth requirements. As zebrafish grow into juveniles (30–90 dpf),

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5084-709: The most common aquaculture species. Because the most common are salmonids and cod in the Protacanthopterygii and sea bass , sea bream , tilapia , and flatfish , in the Percomorpha , zebrafish results may not be perfectly applicable. Various other models – Goldfish ( Carassius auratus ), Medaka ( Oryzias latipes ), Stickleback ( Gasterosteus aculeatus ), Roach ( Rutilus rutilus ), Pufferfish ( Takifugu rubripes ), Swordtail ( Xiphophorus hellerii ) – are less used normally but would be closer to particular target species. The only exception are

5166-460: The mother – will prevent initiation of the mesoderm or endoderm development processes in this species.) In 1999, the nacre mutation was identified in the zebrafish ortholog of the mammalian MITF transcription factor. Mutations in human MITF result in eye defects and loss of pigment, a type of Waardenburg Syndrome . In December 2005, a study of the golden strain identified the gene responsible for its unusual pigmentation as SLC24A5 ,

5248-467: The normal exploratory behavior. This demonstrates relationships between glucocorticoids, fluoxetine, and exploration in this fish. Zebrafish have been used as a model for studying DNA repair pathways. Embryos of externally fertilized fish species, such as zebrafish during their development, are directly exposed to environmental conditions such as pollutants and reactive oxygen species that may cause damage to their DNA . To cope with such DNA damages,

5330-428: The opportunity, adults eat hatchlings, which may be protected by separating the two groups with a net, breeding box or separate tank. In captivity, zebrafish live approximately forty-two months. Some captive zebrafish can develop a curved spine. They can range from a few centimeters to a few inches, and provide movement in a freshwater fish tank. The zebra danio was also used to make genetically modified fish and were

5412-689: The presence of a dense field of dark chromatophores spread homogeneously over the posterior one half of the body unlike the lack of such pigmentation in all congeners. The black widow tetra is a shoaling fish that feeds on small crustaceans , insects , and worms . The black skirt tetra is a common fish that is widely available for purchase. Hobbyists often provide live foods such as Daphnia and mosquito larvae , and frozen foods like bloodworms . The species reaches sexual maturity at about two years of age. Like most characins, this species spawns by intermittently releasing and fertilizing eggs among plants. It frequently eats its own eggs, so keepers remove

5494-429: The process, such as Wnt signaling and Fibroblast growth factor . In probing disorders of the nervous system, including neurodegenerative diseases, movement disorders, psychiatric disorders and deafness, researchers are using the zebrafish to understand how the genetic defects underlying these conditions cause functional abnormalities in the human brain, spinal cord and sensory organs. Researchers have also studied

5576-455: The public's positive reaction to controversial agricultural and aesthetic biotechnologies. The practical reception of GloFish among fish retailers was found to be affected by multiple effects, including concerns over ethics, customer demand, and the high cost of stocking the fish. Some retailers opted not to stock the fish due to low trust in federal agencies to properly regulate the organisms. GloFish are more vulnerable to predation compared to

5658-584: The recommended feeding rate decreases to about 6–8% of their BW per day, with a focus on high-quality dry feeds that meet their protein and energy needs. Upon reaching adulthood (over 90 dpf), zebrafish typically require a feeding rate of around 5% of their BW per day. Throughout these stages, it is essential to adjust the particle size of the feed: less than 100 μm for newly hatched larvae, 100–200 μm for those between 16 and 30 dpf, and larger particles for juveniles and adults. This structured approach to feeding not only supports optimal growth and health but also enhances

5740-551: The reliability of experimental outcomes in research settings Zebrafish are hardy fish and considered good for beginner aquarists. Their enduring popularity can be attributed to their playful disposition, as well as their rapid breeding, aesthetics, cheap price and broad availability. They also do well in schools or shoals of six or more, and interact well with other fish species in the aquarium. However, they are susceptible to Oodinium or velvet disease, microsporidia ( Pseudoloma neurophilia ), and Mycobacterium species. Given

5822-509: The role of two of these elements in oocytes of this species. By interfering via a dominant nonfunctional allele and a morpholino they find the T-box transcription activator Eomesodermin and its target mtx2 – a transcription factor – are vital to epiboly . (In Bruce et al. 2003 they failed to support the possibility that Eomesodermin behaves like Vegt . Neither they nor anyone else has been able to locate any mutation which – in

5904-678: The same time, a separate deal was made between Taikong, the largest aquarium fish producer in Taiwan, and the Taiwanese researchers to market the green medaka in Taiwan under the name TK-1. In the spring of 2003, Taiwan became the first to authorize sales of a genetically modified organism as a pet. One hundred thousand fish were reportedly sold in less than a month at US$ 18.60 each. The fluorescent medaka are not GloFish, as they are not marketed by Yorktown Technologies, but instead by Taikong Corp under

5986-406: The side of the body, which are reminiscent of a zebra's stripes, and which extend to the end of the caudal fin . Its shape is fusiform and laterally compressed, with its mouth directed upwards. The male is torpedo -shaped, with gold stripes between the blue stripes; the female has a larger, whitish belly and silver stripes instead of gold. Adult females exhibit a small genital papilla in front of

6068-414: The sides of the yolk (8 h panel) and begin forming a head and tail (16 h panel). The tail then grows and separates from the body (24 h panel). The yolk shrinks over time because the fish uses it for food as it matures during the first few days (72 h panel). After a few months, the adult fish reaches reproductive maturity (bottom panel). To encourage the fish to spawn, some researchers use a fish tank with

6150-431: The way in which FDA regulates all GM animals, including GloFish. Research published in 2014 assessed the environmental safety associated with GloFish. One paper concluded that there is little risk of invasiveness into the environment. A second study concluded that there is no difference in risk between GloFish and wild-type danios. The sentiments of aquarium retailers towards the GloFish have been used as an indicator of

6232-438: The wild type, according to a study published in 2011. In experiments including habitat complexity, transgenic red fluorescent zebrafish were approximately twice as vulnerable as the wild type to predation by largemouth bass ( Micropterus salmoides ) and eastern mosquitofish ( Gambusia holbrooki ), two native predators that potentially resist invasion by introduced fish. According to Howard et al. 2015, wild-type males had

6314-460: The zebrafish reference genome revealed over 5 million single nucleotide variations and over 1.6 million insertion deletion variations. The zebrafish reference genome sequence of 1.4GB and over 26,000 protein coding genes was published by Kerstin Howe et al. in 2013. In October 2001, researchers from the University of Oklahoma published D. rerio's complete mitochondrial DNA sequence. Its length

6396-473: The zebrafish to gain new insights into the complexities of human musculoskeletal diseases, such as muscular dystrophy . Another focus of zebrafish research is to understand how a gene called Hedgehog , a biological signal that underlies a number of human cancers, controls cell growth. Inbred strains and traditional outbred stocks have not been developed for laboratory zebrafish, and the genetic variability of wild-type lines among institutions may contribute to

6478-467: Was found in other teleosts , but not in tetrapods . This indicates that an evolutionary change in tetrapods may have led to humans relying on the U2AF2 protein for RNA splicing while these genes in zebrafish undergo splicing regardless of the presence of the protein. D. rerio has three transferrins , all of which cluster closely with other vertebrates . When close relatives mate, progeny may exhibit

6560-409: Was found to be without merit and dismissed on March 30, 2005. In addition to the red zebrafish, Yorktown Technologies released green and orange-yellow versions of the zebrafish in mid-2006. In 2011, blue and purple zebrafish were released. These lines of fish incorporate genes from sea coral. In 2012, Yorktown Technologies introduced a green version of a GloFish derived from a different species of fish,

6642-435: Was only 12.3 °C (54.1 °F) and another unusually warm site was 38.6 °C (101.5 °F), but the zebrafish still appeared healthy. The unusually cold temperature was at one of the highest known zebrafish locations at 1,576 m (5,171 ft) above sea level, although the species has been recorded to 1,795 m (5,889 ft). The zebrafish is named for the five uniform, pigmented, horizontal, blue stripes on

6724-445: Was shown to be a complex genetic trait, rather than to follow a simple ZW or XY system. The zebrafish embryo develops rapidly, with precursors to all major organs appearing within 36 hours of fertilization. The embryo begins as a yolk with a single enormous cell on top (see image, 0 h panel), which divides into two (0.75 h panel) and continues dividing until there are thousands of small cells (3.25 h panel). The cells then migrate down

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