Topic: Genetics
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π Atomic gardening
Atomic gardening is a form of mutation breeding where plants are exposed to radioactive sources, typically cobalt-60, in order to generate mutations, some of which have turned out to be useful.
The practice of plant irradiation has resulted in the development of over 2000 new varieties of plants, most of which are now used in agricultural production. One example is the resistance to verticillium wilt of the "Todd's Mitcham" cultivar of peppermint which was produced from a breeding and test program at Brookhaven National Laboratory from the mid-1950s. Additionally, the Rio Star Grapefruit, developed at the Texas A&M Citrus Center in the 1970s, now accounts for over three quarters of the grapefruit produced in Texas.
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- "Atomic Gardening" | 2023-08-11 | 18 Upvotes 1 Comments
- "Atomic Gardening" | 2021-05-21 | 188 Upvotes 96 Comments
- "Atomic Gardening" | 2021-05-03 | 18 Upvotes 1 Comments
- "Atomic gardening" | 2015-05-15 | 22 Upvotes 4 Comments
π Svalbard Global Seed Vault
The Svalbard Global Seed Vault (Norwegian: Svalbard globale frΓΈhvelv) is a secure seed bank on the Norwegian island of Spitsbergen in the remote Arctic Svalbard archipelago. Conservationist Cary Fowler, in association with the Consultative Group on International Agricultural Research (CGIAR), started the vault to preserve a wide variety of plant seeds that are duplicate samples, or "spare" copies, of seeds held in gene banks worldwide. The seed vault is an attempt to ensure against the loss of seeds in other genebanks during large-scale regional or global crises. The seed vault is managed under terms spelled out in a tripartite agreement among the Norwegian government, the Crop Trust, and the Nordic Genetic Resource Center (NordGen).
The Norwegian government entirely funded the vault's approximately 45 million kr (US$8.8 million in 2008) construction. Storing seeds in the vault is free to end users; Norway and the Crop Trust pay for operational costs. Primary funding for the Trust comes from organisations such as the Bill & Melinda Gates Foundation and from various governments worldwide.
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- "Svalbard Global Seed Vault" | 2019-06-13 | 108 Upvotes 13 Comments
- "Svalbard Global Seed Vault" | 2016-05-15 | 63 Upvotes 11 Comments
π Mirror life
Mirror life (also called mirror-image life, chiral life, or enantiomeric life) is a hypothetical form of life with mirror-reflected molecular building blocks. The possibility of mirror life was first discussed by Louis Pasteur. Although this alternative life form has not been discovered in nature, efforts to build a mirror-image version of biology's molecular machinery are already underway.
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- "Mirror life" | 2018-09-09 | 145 Upvotes 35 Comments
π Spiegelman's Monster
Spiegelman's Monster is the name given to an RNA chain of only 218 nucleotides that is able to be reproduced by the RNA replication enzyme RNA-dependent RNA polymerase, also called RNA replicase. It is named after its creator, Sol Spiegelman, of the University of Illinois at Urbana-Champaign who first described it in 1965.
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- "Spiegelman's Monster" | 2016-06-06 | 125 Upvotes 34 Comments
π Belyayev's Fox Experiment
Dmitry Konstantinovich Belyayev (Russian: ΠΠΌΠΈΜΡΡΠΈΠΉ ΠΠΎΠ½ΡΡΠ°Π½ΡΠΈΜΠ½ΠΎΠ²ΠΈΡ ΠΠ΅Π»ΡΜΠ΅Π², 17 July 1917 β 14 November 1985) was a Russian geneticist and academician who served as director of the Institute of Cytology and Genetics (IC&G) of the USSR Academy of Sciences, Novosibirsk, from 1959 to 1985. His decades-long effort to breed domesticated foxes was described by The New York Times as βarguably the most extraordinary breeding experiment ever conducted.β A 2010 article in Scientific American stated that Belyayev βmay be the man most responsible for our understanding of the process by which wolves were domesticated into our canine companions.β
Beginning in the 1950s, in order to uncover the genetic basis of the distinctive behavioral and physiological attributes of domesticated animals, Belyayev and his team spent decades breeding the wild silver fox (Vulpes vulpes) and selecting for reproduction only those individuals in each generation that showed the least fear of humans. After several generations of controlled breeding, a majority of the silver foxes no longer showed any fear of humans and often wagged their tails and licked their human caretakers to show affection. They also began to display spotted coats, floppy ears, curled tails, as well as other physical attributes often found in domesticated animals, thus confirming Belyayevβs hypothesis that both the behavioral and physical traits of domesticated animals could be traced to "a collection of genes that conferred a propensity to tamenessβa genotype that the foxes perhaps shared with any species that could be domesticated".
Belyayevβs experiments were the result of a politically motivated demotion, in response to defying the now discredited non-Mendellian theories of Lysenkoism, which were politically accepted in the Soviet Union at the time. Belyayev has since been vindicated in recent years by major scientific journals, and by the Soviet establishment as a pioneering figure in modern genetics.
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- "Belyayev's Fox Experiment" | 2020-01-25 | 109 Upvotes 30 Comments
π HeLa, the oldest and most commonly used human cell line
HeLa (; also Hela or hela) is an immortal cell line used in scientific research. It is the oldest and most commonly used human cell line. The line was derived from cervical cancer cells taken on February 8, 1951 from Henrietta Lacks, a patient who died of cancer on October 4, 1951. The cell line was found to be remarkably durable and prolific, which gives rise to its extensive use in scientific research.
The cells from Lacks's cancerous cervical tumor were taken without her knowledge or consent, which was common practice at the time. Cell biologist George Otto Gey found that they could be kept alive, and developed a cell line. Previously, cells cultured from other human cells would only survive for a few days. Scientists would spend more time trying to keep the cells alive than performing actual research on them. Cells from Lacks' tumor behaved differently. As was custom for Gey's lab assistant, she labeled the culture 'HeLa', the first two letters of the patient's first and last name; this became the name of the cell line.
These were the first human cells grown in a lab that were naturally "immortal", meaning that they do not die after a set number of cell divisions (i.e. cellular senescence). These cells could be used for conducting a multitude of medical experimentsβif the cells died, they could simply be discarded and the experiment attempted again on fresh cells from the culture. This represented an enormous boon to medical and biological research, as previously stocks of living cells were limited and took significant effort to culture.
The stable growth of HeLa enabled a researcher at the University of Minnesota hospital to successfully grow polio virus, enabling the development of a vaccine, and by 1952, Jonas Salk developed a vaccine for polio using these cells. To test Salk's new vaccine, the cells were put into mass production in the first-ever cell production factory.
In 1953, HeLa cells were the first human cells successfully cloned and demand for the HeLa cells quickly grew in the nascent biomedical industry. Since the cells' first mass replications, they have been used by scientists in various types of investigations including disease research, gene mapping, effects of toxic substances on organisms, and radiation on humans. Additionally, HeLa cells have been used to test human sensitivity to tape, glue, cosmetics, and many other products.
Scientists have grown an estimated 50 million metricΒ tons of HeLa cells, and there are almost 11,000Β patents involving these cells.
The HeLa cell lines are also notorious for invading other cell cultures in laboratory settings. Some have estimated that HeLa cells have contaminated 10β20% of all cell lines currently in use.
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- "HeLa, the oldest and most commonly used human cell line" | 2015-10-30 | 54 Upvotes 12 Comments
- "Immortal cells of Henrietta Lacks" | 2010-02-01 | 36 Upvotes 7 Comments
π Russian Domesticated Red Fox
The Russian domesticated red fox is a form of the wild red fox (Vulpes vulpes) which has been domesticated to an extent, under laboratory conditions. They are the result of an experiment which was designed to demonstrate the power of selective breeding to transform species, as described by Charles Darwin in On the Origin of Species. The experiment was purposely designed to replicate the process that had produced dogs from wolves, by recording the changes in foxes, when in each generation only the most tame foxes were allowed to breed. In short order, the descendant foxes became tamer and more dog-like in their behavior.
The program was started in 1959 in the Soviet Union by zoologist Dmitry Belyayev and it has been in continuous operation since. Today, the experiment is under the supervision of Lyudmila Trut, in Russia, at the Institute of Cytology and Genetics in Novosibirsk.
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- "Russian Domesticated Red Fox" | 2015-11-06 | 96 Upvotes 30 Comments
π Last universal ancestor
The last universal common ancestor (LUCA), also called the last universal ancestor (LUA),Β or concestor, is the most recent population of organisms from which all organisms now living on Earth have a common descent, the most recent common ancestor of all current life on Earth. (A related concept is that of progenote.) LUCA is not thought to be the first life on Earth but only one of many early organisms, all the others becoming extinct.
While there is no specific fossil evidence of LUCA, it can be studied by comparing the genomes of all modern organisms, its descendants. By this means, a 2016 study identified a set of 355 genes most likely to have been present in LUCA. (However, some of those genes could have developed later, then spread universally by horizontal gene transfer between archaea and bacteria.) The genes describe a complex life form with many co-adapted features, including transcription and translation mechanisms to convert information from DNA to RNA to proteins. The study concluded that the LUCA probably lived in the high-temperature water of deep sea vents near ocean-floor magma flows.
Studies from 2000 to 2018 have suggested an increasingly ancient time for LUCA. In 2000, estimations suggested LUCA existed 3.5 to 3.8 billion years ago in the Paleoarchean era, a few hundred million years after the earliest fossil evidence of life, for which there are several candidates ranging in age from 3.48 to 4.28 billion years ago. A 2018 study from the University of Bristol, applying a molecular clock model, places the LUCA shortly after 4.5 billion years ago, within the Hadean.
Charles Darwin first proposed the theory of universal common descent through an evolutionary process in his book On the Origin of Species in 1859: "Therefore I should infer from analogy that probably all the organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first breathed." Later biologists have separated the problem of the origin of life from that of the LUCA.
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- "Last universal ancestor" | 2015-04-05 | 63 Upvotes 24 Comments
π DNA origami
DNA origami is the nanoscale folding of DNA to create non-arbitrary two- and three-dimensional shapes at the nanoscale. The specificity of the interactions between complementary base pairs make DNA a useful construction material, through design of its base sequences. DNA is a well-understood material that is suitable for creating scaffolds that hold other molecules in place or to create structures all on its own.
DNA origami was the cover story of Nature on March 16, 2006. Since then, DNA origami has progressed past an art form and has found a number of applications from drug delivery systems to uses as circuitry in plasmonic devices; however, most applications remain in a concept or testing phase.
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- "DNA origami" | 2016-12-22 | 37 Upvotes 5 Comments
π Horizontal Gene Transfer
Horizontal gene transfer (HGT) or lateral gene transfer (LGT) is the movement of genetic material between unicellular and/or multicellular organisms other than by the ("vertical") transmission of DNA from parent to offspring (reproduction). HGT is an important factor in the evolution of many organisms.
Horizontal gene transfer is the primary mechanism for the spread of antibiotic resistance in bacteria, and plays an important role in the evolution of bacteria that can degrade novel compounds such as human-created pesticides and in the evolution, maintenance, and transmission of virulence. It often involves temperate bacteriophages and plasmids. Genes responsible for antibiotic resistance in one species of bacteria can be transferred to another species of bacteria through various mechanisms of HGT such as transformation, transduction and conjugation, subsequently arming the antibiotic resistant genes' recipient against antibiotics. The rapid spread of antibiotic resistance genes in this manner is becoming medically challenging to deal with. Ecological factors may also play a role in the LGT of antibiotic resistant genes. It is also postulated that HGT promotes the maintenance of a universal life biochemistry and, subsequently, the universality of the genetic code.
Most thinking in genetics has focused upon vertical transfer, but the importance of horizontal gene transfer among single-cell organisms is beginning to be acknowledged.
Gene delivery can be seen as an artificial horizontal gene transfer, and is a form of genetic engineering.
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- "Horizontal gene transfer" | 2014-04-29 | 14 Upvotes 1 Comments