Drosophila melanogaster, the common fruit fly, has been used to study the effects of spaceflight on living organisms.
On a July 9, 1946, suborbital V-2 rocket flight, fruit flies became the first living and sentient organisms to go to space, and on February 20, 1947, fruit flies safely returned from a suborbital space flight, which paved the way for human exploration. For years before sending mammals into space, such as the 1949 flight of the rhesus monkey Albert II, the Soviet space dogs, or humans, scientists studied Drosophila melanogaster (the common fruit fly) and its reactions to both radiation and space flight to understand the possible effects of space and a zero-gravity environment on humans. Starting in the 1910s, researchers conducted experiments on fruit flies because humans and fruit flies share many genes.
At the height of the Cold War and the Space Race, flies were sent on missions to space with great frequency, allowing scientists to study the nature of living and breeding in space. Scientists and researchers from the Soviet Union and the United States both used fruit flies for their research and missions.
Fruit flies have been used in recent years as the reality of Mars and Moon colonization becomes clearer. These flies further the understanding of the effects of weightlessness on the cardiovascular system, the immune system, and the genes of astronauts. Fruit flies have been invaluable assets to scientific discoveries that humankind has made, especially discoveries about space travel.
Background
Even after the Space Race was completed, advancements in space travel continued. Researchers continue to study the ability of life to survive in the harsh atmosphere of space, promote commercial development, expand and advance knowledge, and prepare future generations for exploration.[1] Throughout time, Animals in space have ensured suitable conditions for human exploration. Larger animals including dogs, monkeys, cats, mice, tortoises and others, have been vital to many excursions, as have insects.
The fruit fly has frequently been utilized for space travel, due to its comparable genetics to that of humans.[2] The short gestation period and quick maturing process allows their continued use. Additionally, a female fruit fly can lay one hundred eggs daily, and each egg requires less than ten days to fully mature. Since three-quarters of its genome compares to other organisms, fruit flies frequently proceed with humans in space travel because their entire genetic makeup, including the sex chromosomes, have been sequenced by scientists.[1]
History
Pre-1930
Scientists began using fruit flies for research as early as 1907. The first fruit fly research was performed by Thomas Hunt Morgan. He exposed flies to radiation and realized that they were a medical miracle, in the sense that they provided test results that are very often mirrored across many other species of animals. He studied fifteen different types of fruit flies, including the fruit fly most widely known, the Drosophila melanogaster. He established the "fly room" at the University of Columbia, dedicated and reserved to all the research being conducted on flies.[3]
1930s
In the 1930s, Dobzhanksy used research from Charles Darwin. Rather than focus on the idea of survival of the fittest, Dobzhanksy focused on gene pools. Even though fruit flies are very small, they had the largest chromosomes that scientists had yet observed, making his research groundbreaking.[3] In 1933, Thomas Hunt Morgan won a Nobel Prize for his research in medicine using flies.[3] In 1935, Albert William Stevens and Orvil Arson Anderson ascended to 72,395 feet in a special balloon aircraft, and they carried fruit flies on their flight with them.[4]
1946 and 1947, first spaceflights carrying Earthlings
On July 9 1946, the first fruit flies reached space but were not recovered.[5] On February 20, 1947, the United States sent a V-2 rocket containing fruit flies into space to study the effects of radiation on living organisms and to see if the radiation from space would be a potential problem for future astronauts.[6] The flight was launched from White Sands Missile Range in New Mexico and lasted a total of three minutes. All the flies returned to Earth untouched by radiation. These flies paved the way for space-bound monkeys in 1949, dogs in 1957, and eventually humans in 1961.[6]
1950s
In February 1953, the United States launched several unmanned balloons containing fruit flies in various experiments. Most of the flies died or were never recovered, but twelve flies survived one flight on February 26, 1953.[4] In February 1956, an unmanned balloon carrying mice, guinea pigs, a fungus sample, and some fruit flies reached an altitude of 115,000 feet. The mission proved successful: all the animals were recovered alive.[4] In July 1958, the United States Navy launched Malcolm David Ross, Morton Lee Lewis, and fruit flies in a manned high-altitude balloon to 82,000 feet.[7] This was the first flight that reached the stratosphere, where the cabin of the balloon mimicked the pressurized conditions found at a sea-level environment.[7]
1960s
In 1961, the first humans were sent to space.[6] In 1968, scientists found that fruit fly larvae exposed to both radiation and space flight had a higher rate of premature death compared to fruit flies that were only exposed to radiation or fruit flies that only went to space.[8] The same study showed that the flies exposed to both radiation and space flight also experienced accelerated aging and genetic mutations. A different 1968 study with the same general premise of exposing fruit flies to both pre-flight radiation and space flight showed that flies exposed to both had significant damage to their sperm, as opposed to flies exposed to only one or the other.[9]
1970s
A 1978 publication included several key findings that were critical for scientists studying fruit flies sent into space. First, fruit flies who were born and spent their first few days in space had a shorter lifespan than Earth-bound flies. Second, the development process of flies born in space and living flies sent to space was regular. Third, the wings of flies that were sent to space were either physically damaged (most likely due to the nature of the takeoff and landing of the Space Shuttle and not because of the micro-gravitational environment) or genetically damaged, since flies born in space did not produce as much glycogen in their wings, thus inhibiting their ability to fly.[1]
1980s
In 1981, Soviet scientists concluded that flies which were exposed to radiation before they were sent into orbit were far more likely to have offspring that exhibited genetic mutations than fruit flies that were only exposed to radiation or fruit flies that were only sent to space.[10]
1990s
In 1997, researchers sent fruit flies into space for eight days and mated them with earthbound fruit flies upon their return. They then produced male fruit flies that were three times as likely to carry lethal mutations on the Y-chromosome. These researchers suggested that the mutations were a result of the radiation found in space.[11]
2000s
A 2006 study found that fruit flies born in space were more vulnerable and susceptible to illness, and had a far weaker immune system compared to fruit flies born on Earth.[2] This study confirmed to scientists that any plans for the Moon or Mars colonization would need to include countermeasures to boost astronauts' immune systems against infections like sepsis.[12]
2010s
In 2012, Dr. Richard Hill used a powerful magnet that simulated a zero-gravity experience to study the effect on fruit flies. Hill found that the flies' speed increased and that instead of floating, the flies moved in a motion similar to walking.[13] The effect of weightlessness on fruit flies that Dr. Hill studied can give researchers valuable insights to the effects of weightlessness on humans since humans and fruit flies have very similar genes. In 2015, scientists from the Sanford Burnham Prebys Medical Discovery Institute found that fruit flies sent to space experienced changes in their genes that controlled their hearts and other cardiovascular structures.[14] In 2017, the same scientists sent 30 live fruit flies with 2,000 fruit fly eggs to further research on the effects of zero-gravity on the heart and cardiovascular system.[14] They found that the hearts of fruit flies that lived in space for several weeks were anatomically different from the hearts of earthbound fruit flies. From this study, scientists concluded that plans for Moon or Mars colonization would also have to include specific plans to protect astronauts' hearts.[15]
2020s and ongoing
With the technological advancements that exist today, space-like conditions can be replicated on Earth. This allows research to continue regarding the supposed effects of space travel on organisms and their body systems, without the costly nature of space expeditions. While technology advances, the fruit fly is continually used in preliminary research regarding space travel and organisms. Based on past research stating the dangerous consequences of space travel on blood flow and heart health, current research is being conducted. With time, research specialists hope to find results to combat these negative side effects and promote safe space travel.[15]
See also
Zond 5, 1968 USSR Moon mission which carried fruit fly eggs
1 2 3 Mains, Richard, Sharon Reynolds, Matthew Lera, and Lance Ellingson. A Researcher's Guide to Fruit Fly Research. Houston, Texas: NASA ISS Program Science Office, 2016.
1 2 3 Beischer, DE; Fregly, AR (1962). "Animals and man in space. A chronology and annotated bibliography through the year 1960". US Naval School of Aviation Medicine. ONR TR ACR-64 (AD0272581).
↑ Browning, L., and Altenburg, E. (1968). Effects of the space environment on radiation-induced damage in mature reproductive cells of adult Drosophila and in spermatocytes of the immature testis. Radiat. Res. 35, 500–501.
Drosophila is a genus of flies, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit. They should not be confused with the Tephritidae, a related family, which are also called fruit flies ; tephritids feed primarily on unripe or ripe fruit, with many species being regarded as destructive agricultural pests, especially the Mediterranean fruit fly.
Drosophila melanogaster is a species of fly 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.
Hermann Joseph Muller was an American geneticist, educator, and Nobel laureate best known for his work on the physiological and genetic effects of radiation (mutagenesis), as well as his outspoken political beliefs. Muller frequently warned of long-term dangers of radioactive fallout from nuclear war and nuclear testing, which resulted in greater public scrutiny of these practices.
A genetic screen or mutagenesis screen is an experimental technique used to identify and select individuals who possess a phenotype of interest in a mutagenized population. Hence a genetic screen is a type of phenotypic screen. Genetic screens can provide important information on gene function as well as the molecular events that underlie a biological process or pathway. While genome projects have identified an extensive inventory of genes in many different organisms, genetic screens can provide valuable insight as to how those genes function.
STS-42 was a NASA Space Shuttle Discovery mission with the Spacelab module. Liftoff was originally scheduled for 8:45 EST on January 22, 1992, but the launch was delayed due to weather constraints. Discovery successfully lifted off an hour later at 9:52:33 EST. The main goal of the mission was to study the effects of microgravity on a variety of organisms. The shuttle landed at 8:07:17 PST on January 30, 1992, on Runway 22, Edwards Air Force Base, California. STS-42 was the first of two flights in 1992 of Discovery, the second of which occurred during STS-53, which launched on December 2, 1992. The mission was also the last mission of the Space Shuttle Discovery to have a seven-member crew until STS-82, which was launched on February 11, 1997.
Animals in space originally served to test the survivability of spaceflight, before human spaceflights were attempted. Later, other non-human animals were flown to investigate various biological processes and the effects microgravity and space flight might have on them. Bioastronautics is an area of bioengineering research that spans the study and support of life in space. To date, seven national space programs have flown animals into space: the United States, Soviet Union, France, Argentina, China, Japan and Iran.
Mosaicism or genetic mosaicism is a condition in which a multicellular organism possesses more than one genetic line as the result of genetic mutation. This means that various genetic lines resulted from a single fertilized egg. Mosaicism is one of several possible causes of chimerism, wherein a single organism is composed of cells with more than one distinct genotype.
Venturing into the environment of space can have negative effects on the human body. Significant adverse effects of long-term weightlessness include muscle atrophy and deterioration of the skeleton. Other significant effects include a slowing of cardiovascular system functions, decreased production of red blood cells, balance disorders, eyesight disorders and changes in the immune system. Additional symptoms include fluid redistribution, loss of body mass, nasal congestion, sleep disturbance, and excess flatulence. Overall, NASA refers to the various deleterious effects of spaceflight on the human body by the acronym RIDGE.
Genetic assimilation is a process described by Conrad H. Waddington by which a phenotype originally produced in response to an environmental condition, such as exposure to a teratogen, later becomes genetically encoded via artificial selection or natural selection. Despite superficial appearances, this does not require the (Lamarckian) inheritance of acquired characters, although epigenetic inheritance could potentially influence the result. Waddington stated that genetic assimilation overcomes the barrier to selection imposed by what he called canalization of developmental pathways; he supposed that the organism's genetics evolved to ensure that development proceeded in a certain way regardless of normal environmental variations.
Balancer chromosomes are a type of genetically engineered chromosome used in laboratory biology for the maintenance of recessive lethal mutations within living organisms without interference from natural selection. Since such mutations are viable only in heterozygotes, they cannot be stably maintained through successive generations and therefore continually lead to production of wild-type organisms, which can be prevented by replacing the homologous wild-type chromosome with a balancer. In this capacity, balancers are crucial for genetics research on model organisms such as Drosophila melanogaster, the common fruit fly, for which stocks cannot be archived. They can also be used in forward genetics screens to specifically identify recessive lethal mutations. For that reason, balancers are also used in other model organisms, most notably the nematode worm Caenorhabditis elegans and the mouse.
Most animal testing involves invertebrates, especially Drosophila melanogaster, a fruit fly, and Caenorhabditis elegans, a nematode. These animals offer scientists many advantages over vertebrates, including their short life cycle, simple anatomy and the ease with which large numbers of individuals may be studied. Invertebrates are often cost-effective, as thousands of flies or nematodes can be housed in a single room.
The GAL4-UAS system is a biochemical method used to study gene expression and function in organisms such as the fruit fly. It is based on the finding by Hitoshi Kakidani and Mark Ptashne, and Nicholas Webster and Pierre Chambon in 1988 that Gal4 binding to UAS sequences activates gene expression. The method was introduced into flies by Andrea Brand and Norbert Perrimon in 1993 and is considered a powerful technique for studying the expression of genes. The system has two parts: the Gal4 gene, encoding the yeast transcription activator protein Gal4, and the UAS, an enhancer to which GAL4 specifically binds to activate gene transcription.
Neurogenetics studies the role of genetics in the development and function of the nervous system. It considers neural characteristics as phenotypes, and is mainly based on the observation that the nervous systems of individuals, even of those belonging to the same species, may not be identical. As the name implies, it draws aspects from both the studies of neuroscience and genetics, focusing in particular how the genetic code an organism carries affects its expressed traits. Mutations in this genetic sequence can have a wide range of effects on the quality of life of the individual. Neurological diseases, behavior and personality are all studied in the context of neurogenetics. The field of neurogenetics emerged in the mid to late 20th century with advances closely following advancements made in available technology. Currently, neurogenetics is the center of much research utilizing cutting edge techniques.
Weightlessness is the complete or near-complete absence of the sensation of weight. It is also termed zero gravity, zero G-force, or zero-G. Micro-g environment is more or less synonymous, with the recognition that g-forces are never exactly zero.
A genetically modified (GM) insect is an insect that has been genetically modified, either through mutagenesis, or more precise processes of transgenesis, or cisgenesis. Motivations for using GM insects include biological research purposes and genetic pest management. Genetic pest management capitalizes on recent advances in biotechnology and the growing repertoire of sequenced genomes in order to control pest populations, including insects. Insect genomes can be found in genetic databases such as NCBI, and databases more specific to insects such as FlyBase, VectorBase, and BeetleBase. There is an ongoing initiative started in 2011 to sequence the genomes of 5,000 insects and other arthropods called the i5k. Some Lepidoptera have been genetically modified in nature by the wasp bracovirus.
Endless Forms Most Beautiful: The New Science of Evo Devo and the Making of the Animal Kingdom is a 2005 book by the molecular biologist Sean B. Carroll. It presents a summary of the emerging field of evolutionary developmental biology and the role of toolkit genes. It has won numerous awards for science communication.
A behaviour mutation is a genetic mutation that alters genes that control the way in which an organism behaves, causing their behavioural patterns to change.
Genetics of aging is generally concerned with life extension associated with genetic alterations, rather than with accelerated aging diseases leading to reduction in lifespan.
The following page is a list of scientific research that is currently underway or has been previously studied on the International Space Station by the European Space Agency.
Biosatellite 2, also known as Biosat 2 or Biosatellite B, was the second mission in NASA's Biosatellite program for biological research. It was launched on September 7, 1967, by a Delta G rocket from Cape Canaveral Air Force Station in Florida.
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