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64-473: Teneurins are highly conserved between Drosophila , C. elegans and vertebrates . In each species, they are expressed by a subset of neurons as well as at sites of pattern formation and morphogenesis. In Drosophila , a teneurin known as ten-m or Odz is a pair-rule gene, and its expression is required for normal development. The knockdown of teneurin ( ten-1 ) expression in C. elegans with RNAi leads to abnormal neuronal pathfinding and abnormal development of

128-496: A hypoxia treatment experience decreased thorax length, while hyperoxia produces smaller flight muscles, suggesting negative developmental effects of extreme oxygen levels. Circadian rhythms are also subject to developmental plasticity. Light conditions during development affect daily activity patterns in Drosophila melanogaster , where flies raised under constant dark or light are less active as adults than those raised under

192-806: A 12-hour light/dark cycle. Temperature is one of the most pervasive factors influencing arthropod development. In Drosophila melanogaster temperature-induced developmental plasticity can be beneficial and/or detrimental. Most often lower developmental temperatures reduce growth rates which influence many other physiological factors. For example, development at 25 °C increases walking speed, thermal performance breadth , and territorial success, while development at 18 °C increases body mass, wing size, all of which are tied to fitness. Moreover, developing at certain low temperatures produces proportionally large wings which improve flight and reproductive performance at similarly low temperatures ( See acclimation ). Drosophilidae The Drosophilidae are

256-419: A cluster of spiky hairs (claspers) surrounding the reproducing parts used to attach to the female during mating. Extensive images are found at FlyBase . Drosophila melanogaster can be distinguished from related species by the following combination of features: gena ~1/10 diameter of eye at greatest vertical height; wing hyaline and with costal index 2.4; male protarsus with a single row of ~12 setae forming

320-470: A common origin. Its geographic range includes all continents, including islands. D. melanogaster is a common pest in homes, restaurants, and other places where food is served. Flies belonging to the family Tephritidae are also called "fruit flies". This can cause confusion, especially in the Mediterranean, Australia , and South Africa , where the Mediterranean fruit fly Ceratitis capitata

384-418: A common vector in propagating acetic acid bacteria in nature. This often ruins the alcohol fermentation process and can ruin beer or wine by turning it into vinegar . There are sinking traps available on the market for this nuisance, but one quick way to strongly limit the extent of it is to vacuum clean the flies both at rest and in their slow flight. The diagnostic characteristics for Drosophilidae include

448-466: A diverse, cosmopolitan family of flies , which includes species called fruit flies, although they are more accurately referred to as vinegar or pomace flies. Another distantly related family of flies, Tephritidae , are true fruit flies because they are frugivorous, and include apple maggot flies and many pests. The best known species of the Drosophilidae is Drosophila melanogaster , within

512-448: A few hundred, very long (1.76 mm) sperm cells in seminal fluid to the female. Females store the sperm in a tubular receptacle and in two mushroom-shaped spermathecae ; sperm from multiple matings compete for fertilization. A last male precedence is believed to exist; the last male to mate with a female sires about 80% of her offspring. This precedence was found to occur through both displacement and incapacitation. The displacement

576-560: A fully formed adult fruit fly. Males perform a sequence of five behavioral patterns to court females. First, males orient themselves while playing a courtship song by horizontally extending and vibrating their wings. Soon after, the male positions himself at the rear of the female's abdomen in a low posture to tap and lick the female genitalia. Finally, the male curls his abdomen and attempts copulation. Females can reject males by moving away, kicking, and extruding their ovipositor. Copulation lasts around 15–20 minutes, during which males transfer

640-578: A genetic model for several human diseases including the neurodegenerative disorders Parkinson's , Huntington's , spinocerebellar ataxia and Alzheimer's disease . The fly is also being used to study mechanisms underlying aging and oxidative stress , immunity , diabetes , and cancer , as well as drug abuse . The life cycle of this insect has four stages: fertilized egg, larva, pupa, and adult. Embryogenesis in Drosophila has been extensively studied, as its small size, short generation time, and large brood size makes it ideal for genetic studies. It

704-529: A greater mating efficiency for experienced males over naïve males. This modification also appears to have obvious evolutionary advantages, as increased mating efficiency is extremely important in the eyes of natural selection . Both male and female D. melanogaster flies act polygamously (having multiple sexual partners at the same time). In both males and females, polygamy results in a decrease in evening activity compared to virgin flies, more so in males than females. Evening activity consists of those in which

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768-778: A laboratory known as the Fly Room. The Fly Room was cramped with eight desks, each occupied by students and their experiments. They started off experiments using milk bottles to rear the fruit flies and handheld lenses for observing their traits. The lenses were later replaced by microscopes, which enhanced their observations. Morgan and his students eventually elucidated many basic principles of heredity, including sex-linked inheritance, epistasis , multiple alleles, and gene mapping . D. melanogaster had historically been used in laboratories to study genetics and patterns of inheritance. However, D. melanogaster also has importance in environmental mutagenesis research, allowing researchers to study

832-597: A region of conserved cysteines and unique YD-repeats. The teneurin intracellular (IC) domain (~300–400 aa) is located at the N-terminus and contains a number of conserved putative tyrosine phosphorylation sites, two EF-hand-like calcium-binding motifs, and two polyproline domains. These proline -rich stretches are characteristic of SH3-binding sites. There is considerable divergence between intracellular domains of invertebrate and vertebrate teneurins as well as between different invertebrate proteins . This domain

896-538: A serious agricultural pest. The leaf mining Scaptomyza flava , which is nested in the genus Drosophila phylogenetically , is an obligate leaf miner of mustard plants, including the model plant Arabidopsis thaliana and is a major pest of salad brassicas in New Zealand and an emerging pest of canola in the UK. Drosophila repleta larvae inhabit drains and spread bacteria. Fruit flies in general are considered as

960-443: A sex comb; male epandrial posterior lobe small and nearly triangular; female abdominal tergite 6 with dark band running to its ventral margin; female oviscapt small, pale, without dorsodistal depression and with 12-13 peg-like outer ovisensilla. Drosophila melanogaster flies can sense air currents with the hairs on their backs. Their eyes are sensitive to slight differences in light intensity and will instinctively fly away when

1024-510: A shadow or other movement is detected. Under optimal growth conditions at 25 °C (77 °F), the D. melanogaster lifespan is about 50 days from egg to death. The developmental period for D. melanogaster varies with temperature, as with many ectothermic species. The shortest development time (egg to adult), seven days, is achieved at 28 °C (82 °F). Development times increase at higher temperatures (11 days at 30 °C or 86 °F) due to heat stress. Under ideal conditions,

1088-447: Is a holometabolous insect, so it undergoes a full metamorphosis. Their life cycle is broken down into four stages: embryo, larva, pupa, adult. The eggs, which are about 0.5 mm long, hatch after 12–15 hours (at 25 °C or 77 °F). The resulting larvae grow for about four days (at 25 °C) while molting twice (into second- and third-instar larvae), at about 24 and 48 hours after hatching. During this time, they feed on

1152-409: Is also unique among model organisms in that cleavage occurs in a syncytium . During oogenesis, cytoplasmic bridges called "ring canals" connect the forming oocyte to nurse cells. Nutrients and developmental control molecules move from the nurse cells into the oocyte. In the figure to the left, the forming oocyte can be seen to be covered by follicular support cells. After fertilization of the oocyte,

1216-413: Is an economic pest. The term " Drosophila ", meaning "dew-loving", is a modern scientific Latin adaptation from Greek words δρόσος , drósos , " dew ", and φιλία , philía , "lover". The term " melanogaster " meaning "black-belly", comes from Ancient Greek μέλας , mélas , “black”, and γᾰστήρ , gastḗr , "belly". Unlike humans , the sex and physical appearance of fruit flies

1280-577: Is attributed to sperm handling by the female fly as multiple matings are conducted and is most significant during the first 1–2 days after copulation. Displacement from the seminal receptacle is more significant than displacement from the spermathecae. Incapacitation of first male sperm by second male sperm becomes significant 2–7 days after copulation. The seminal fluid of the second male is believed to be responsible for this incapacitation mechanism (without removal of first male sperm) which takes effect before fertilization occurs. The delay in effectiveness of

1344-468: Is evidence to support that pathogens living within certain flies are beneficial to the behavior and survival of the host. One such example of this is in the fly Scaptomyza flava, which carries the pathogen Pseudomonas syringae in exchange for the pathogen damaging the anti-herbivore defenses of plants in the family Brassicaceae , which are the main food source for the fly. The family contains more than 4,000 species classified under 75 genera. Recently,

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1408-443: Is followed by the name of the gene affected and a description of its phenotype. (Note: Recessive alleles are in lower case, while dominant alleles are capitalised.) Drosophila genes are traditionally named after the phenotype they cause when mutated. For example, the absence of a particular gene in Drosophila will result in a mutant embryo that does not develop a heart. Scientists have thus called this gene tinman , named after

1472-404: Is found in the intracellular N-terminal region of the teneurin family. Human genes encoded teneurin domain proteins (TENM1-4) are list in the infoboxes. Drosophila melanogaster Drosophila melanogaster is a species of fly (an insect of the order Diptera) in the family Drosophilidae . The species is often referred to as the fruit fly or lesser fruit fly , or less commonly

1536-453: Is induced by the DNA damaging agents ultraviolet light and mitomycin C . Females become receptive to courting males about 8–12 hours after emergence. Specific neuron groups in females have been found to affect copulation behavior and mate choice. One such group in the abdominal nerve cord allows the female fly to pause her body movements to copulate. Activation of these neurons induces

1600-408: Is not influenced by hormones . The appearance and sex of fruit flies is determined only by genetic information. Female fruit flies are substantially larger than male fruit flies, with females having bodies that are up to 30% larger than an adult male. Wild type fruit flies are yellow-brown, with brick-red eyes and transverse black rings across the abdomen. The black portions of the abdomen are

1664-422: Is one of the most widely used and genetically best-known of all eukaryotic organisms. All organisms use common genetic systems; therefore, comprehending processes such as transcription and replication in fruit flies helps in understanding these processes in other eukaryotes, including humans . Thomas Hunt Morgan began using fruit flies in experimental studies of heredity at Columbia University in 1910 in

1728-409: Is relatively very small and therefore often ignored, aside from its important eyeless gene. The D. melanogaster sequenced genome of 139.5 million base pairs has been annotated and contains around 15,682 genes according to Ensemble release 73. More than 60% of the genome appears to be functional non-protein-coding DNA involved in gene expression control. Determination of sex in Drosophila occurs by

1792-491: Is sent to a brain region that is a homolog of the hypothalamus and the hypothalamus then controls sexual behavior and desire. Gonadotropic hormones in Drosophila maintain homeostasis and govern reproductive output via a cyclic interrelationship, not unlike the mammalian estrous cycle . Sex peptide perturbs this homeostasis and dramatically shifts the endocrine state of the female by inciting juvenile hormone synthesis in

1856-400: The D. melanogaster homolog of WRN also cause increased physiologic signs of aging, such as shorter lifespan, higher tumor incidence, muscle degeneration, reduced climbing ability, altered behavior and reduced locomotor activity. Meiotic recombination in D. melanogaster appears to be employed in repairing damage in germ-line DNA as indicated by the findings that meiotic recombination

1920-679: The Oz character of the same name . Likewise changes in the Shavenbaby gene cause the loss of dorsal cuticular hairs in Drosophila sechellia larvae. This system of nomenclature results in a wider range of gene names than in other organisms. The genome of D. melanogaster (sequenced in 2000, and curated at the FlyBase database ) contains four pairs of chromosomes – an X/Y pair, and three autosomes labeled 2, 3, and 4. The fourth chromosome

1984-517: The X:A ratio of X chromosomes to autosomes, not because of the presence of a Y chromosome as in human sex determination. Although the Y chromosome is entirely heterochromatic , it contains at least 16 genes, many of which are thought to have male-related functions. There are three transferrin orthologs, all of which are dramatically divergent from those known in chordate models. A June 2001 study by National Human Genome Research Institute comparing

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2048-429: The genus Drosophila , also called the "fruit fly." Drosophila melanogaster is used extensively for studies concerning genetics , development, physiology , ecology and behaviour . Many fundamental biological mechanisms were discovered first in D. melanogaster. The fruit fly is mostly composed of post-mitotic cells, has a very short lifespan, and shows gradual aging. As in other species, temperature influences

2112-409: The mesoderm , and posterior and anterior invagination of endoderm (gut), as well as extensive body segmentation until finally hatching from the surrounding cuticle into a first-instar larva. During larval development, tissues known as imaginal discs grow inside the larva. Imaginal discs develop to form most structures of the adult body, such as the head, legs, wings, thorax, and genitalia. Cells of

2176-429: The microorganisms that decompose the fruit, as well as on the sugar of the fruit itself. The mother puts feces on the egg sacs to establish the same microbial composition in the larvae's guts that has worked positively for herself. Then the larvae encapsulate in the puparium and undergo a four-day-long metamorphosis (at 25 °C), after which the adults eclose (emerge). Drosophila melanogaster, commonly known as

2240-478: The " vinegar fly", " pomace fly", or " banana fly". In the wild, D. melanogaster are attracted to rotting fruit and fermenting beverages, and are often found in orchards, kitchens and pubs. 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 . D. melanogaster

2304-537: The comparable domains of vertebrate teneurins, but the extracellular domains of all of these proteins are remarkably similar. Teneurins translocate to the nucleus where they regulate transcriptional activity. Teneurins promote neurite outgrowth and cell adhesion . The intracellular domain interacts with the DNA-binding transcriptional repressors and also regulate the activity of transcription factors . Additionally, they have been known to interact with

2368-906: The copulation of others). This behavior is sensitive to environmental conditions, and females copulate less in bad weather conditions. D. melanogaster males exhibit a strong reproductive learning curve. That is, with sexual experience, these flies tend to modify their future mating behavior in multiple ways. These changes include increased selectivity for courting only intraspecifically, as well as decreased courtship times. Sexually naïve D. melanogaster males are known to spend significant time courting interspecifically, such as with D. simulans flies. Naïve D. melanogaster will also attempt to court females that are not yet sexually mature, and other males. D. melanogaster males show little to no preference for D. melanogaster females over females of other species or even other male flies. However, after D. simulans or other flies incapable of copulation have rejected

2432-421: The corpus allatum. D. melanogaster is often used for life extension studies, such as to identify genes purported to increase lifespan when mutated . D. melanogaster is also used in studies of aging . Werner syndrome is a condition in humans characterized by accelerated aging. It is caused by mutations in the gene WRN that encodes a protein with essential roles in repair of DNA damage. Mutations in

2496-427: The cytoskeleton adaptor protein, CAP/ponsin, suggesting cell signalling roles and regulation of actin organisation. Teneurin-3 regulates the structural and functional wiring of retinal ganglion cells in the vertebrate visual system . Ten-m1–4, exist as homodimers and undergo homophilic interactions in vertebrates . The large C-terminal extracellular domain consists of eight EGF-like repeats (see PROSITEDOC ),

2560-454: The development time at 25 °C (77 °F) is 8 + 1 ⁄ 2 days, at 18 °C (64 °F) it takes 19 days and at 12 °C (54 °F) it takes over 50 days. Under crowded conditions, development time increases, while the emerging flies are smaller. Females lay some 400 eggs (embryos), about five at a time, into rotting fruit or other suitable material such as decaying mushrooms and sap fluxes . Drosophila melanogaster

2624-405: The early embryo (or syncytial embryo ) undergoes rapid DNA replication and 13 nuclear divisions until about 5000 to 6000 nuclei accumulate in the unseparated cytoplasm of the embryo. By the end of the eighth division, most nuclei have migrated to the surface, surrounding the yolk sac (leaving behind only a few nuclei, which will become the yolk nuclei). After the 10th division, the pole cells form at

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2688-406: The effects of specific environmental mutagens. There are many reasons the fruit fly is a popular choice as a model organism: Genetic markers are commonly used in Drosophila research, for example within balancer chromosomes or P-element inserts, and most phenotypes are easily identifiable either with the naked eye or under a microscope. In the list of a few common markers below, the allele symbol

2752-513: The evolution of herbivory and specialist on toxic mustard leaves. Generally, drosophilids are considered to be nuisance flies rather than pests, since most species breed in rotting material. Zaprionus indianus is unusual among Drosophilidae species in being a serious, primary pest of at least one commercial fruit, figs in Brazil. Another species, Drosophila suzukii , infests thin-skinned fruit such as raspberries and cherries and can be

2816-451: The female fruit fly and are present in the early stages of embryo development. They determine the embryo's main features and early development. For example, the gene called Bicoid regulates the formation of the embryo's anterior end, and its absence leads to an embryo lacking a head. Zygotic genes: These genes are activated in later stages of embryo development when the fruit fly embryo begins to produce its own genetic products. For example,

2880-494: The female to cease movement and orient herself towards the male to allow for mounting. If the group is inactivated, the female remains in motion and does not copulate. Various chemical signals such as male pheromones often are able to activate the group. Also, females exhibit mate choice copying . When virgin females are shown other females copulating with a certain type of male, they tend to copulate more with this type of male afterwards than naïve females (which have not observed

2944-492: The flies participate other than mating and finding partners, such as finding food. The reproductive success of males and females varies, because a female only needs to mate once to reach maximum fertility. Mating with multiple partners provides no advantage over mating with one partner, so females exhibit no difference in evening activity between polygamous and monogamous individuals. For males, however, mating with multiple partners increases their reproductive success by increasing

3008-413: The fruit fly and human genome estimated that about 60% of genes are conserved between the two species. About 75% of known human disease genes have a recognizable match in the genome of fruit flies, and 50% of fly protein sequences have mammalian homologs . An online database called Homophila is available to search for human disease gene homologues in flies and vice versa. Drosophila is being used as

3072-485: The fruit fly, has been a significant model organism in embryonic development research. Many of its genes that regulate embryonic development and their mechanisms of action have been crucial in understanding the fundamental principles of embryonic development regulation in many multicellular organisms, including humans. Here are some important genes regulating embryonic development in Drosophila melanogaster and their modes of action: Maternal genes: These genes are encoded in

3136-529: The genetic diversity of their offspring. This benefit of genetic diversity is an evolutionary advantage because it increases the chance that some of the offspring will have traits that increase their fitness in their environment. The difference in evening activity between polygamous and monogamous male flies can be explained with courtship. For polygamous flies, their reproductive success increases by having offspring with multiple partners, and therefore they spend more time and energy on courting multiple females. On

3200-536: The gonads. The intracellular domain of some, if not all, teneurins can be cleaved and transported to the cell nucleus , where it proposed to act as a transcription factor . A peptide derived from the terminus of the extracellular domain shares structural homology with certain neuropeptides . There are four teneurin genes in vertebrates, named teneurin-1 through -4. Other names found in the literature include Odz-1 through -4 and Tenm-1 through -4. Originally discovered as ten-m and ten-a in Drosophila melanogaster ,

3264-467: The gradient. For example, the Hedgehog morphogen regulates the differentiation of segments and segment identity in the fruit fly embryo. These genes and their modes of action form a complex regulatory network that guides the embryonic development of Drosophila melanogaster. They influence cell differentiation, segment formation, and axial patterning in the embryo, ultimately leading to the development of

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3328-482: The hunchback gene regulates the formation of segments in the embryo. Homeotic genes: This gene family regulates segmentation and axial patterning in development. They act as regulatory factors that determine cell fate in embryonic development. For example, the gene called Antennapedia regulates the formation of anterior limbs in the embryo. Morphogens: These are molecules that form gradients in embryonic development and regulate cell fate depending on their position in

3392-768: The imaginal disks are set aside during embryogenesis and continue to grow and divide during the larval stages—unlike most other cells of the larva, which have differentiated to perform specialized functions and grow without further cell division. At metamorphosis, the larva forms a pupa , inside which the larval tissues are reabsorbed and the imaginal tissues undergo extensive morphogenetic movements to form adult structures. Biotic and abiotic factors experienced during development will affect developmental resource allocation leading to phenotypic variation , also referred to as developmental plasticity. As in all insects, environmental factors can influence several aspects of development in Drosophila melanogaster . Fruit flies reared under

3456-486: The incapacitation mechanism is believed to be a protective mechanism that prevents a male fly from incapacitating his own sperm should he mate with the same female fly repetitively. Sensory neurons in the uterus of female D. melanogaster respond to a male protein, sex peptide , which is found in semen. This protein makes the female reluctant to copulate for about 10 days after insemination . The signal pathway leading to this change in behavior has been determined. The signal

3520-433: The inspiration for the species name ( melanogaster = "black-bellied" ). The brick-red color of the eyes of the wild type fly are due to two pigments: xanthommatin, which is brown and is derived from tryptophan , and drosopterins, which are red and are derived from guanosine triphosphate . They exhibit sexual dimorphism ; females are about 2.5 mm (0.10 in) long; males are slightly smaller. Furthermore, males have

3584-404: The life history of the animal. Several genes have been identified that can be manipulated to extend the lifespan of these insects. Additionally, Drosophila subobscura , also within the genus Drosophila , has been reputed as a model organism for evolutionary-biological studies, along with D. sechellia for the evolution of host specialization on the toxic noni fruit and Scaptomyza flava for

3648-582: The males' advances, D. melanogaster males are much less likely to spend time courting nonspecifically in the future. This apparent learned behavior modification seems to be evolutionarily significant, as it allows the males to avoid investing energy into futile sexual encounters. In addition, males with previous sexual experience modify their courtship dance when attempting to mate with new females—the experienced males spend less time courting, so have lower mating latencies, meaning that they are able to reproduce more quickly. This decreased mating latency leads to

3712-638: The nuclei that have made a mistake detach from their centrosomes and fall into the centre of the embryo (yolk sac), which will not form part of the fly. The gene network (transcriptional and protein interactions) governing the early development of the fruit fly embryo is one of the best understood gene networks to date, especially the patterning along the anteroposterior (AP) and dorsoventral (DV) axes (See under morphogenesis ). The embryo undergoes well-characterized morphogenetic movements during gastrulation and early development, including germ-band extension , formation of several furrows, ventral invagination of

3776-458: The other hand, monogamous flies only court one female, and expend less energy doing so. While it requires more energy for male flies to court multiple females, the overall reproductive benefits it produces has kept polygamy as the preferred sexual choice. The mechanism that affects courtship behavior in Drosophila is controlled by the oscillator neurons DN1s and LNDs. Oscillation of the DN1 neurons

3840-482: The posterior end of the embryo, segregating the germ line from the syncytium. Finally, after the 13th division, cell membranes slowly invaginate, dividing the syncytium into individual somatic cells. Once this process is completed, gastrulation starts. Nuclear division in the early Drosophila embryo happens so quickly, no proper checkpoints exist, so mistakes may be made in division of the DNA. To get around this problem,

3904-611: The presence of an incomplete subcostal vein , two breaks in the costal vein, a small anal cell in the wing , convergent postocellar bristles; and usually three frontal bristles on each side of the head, one directed forward and the other two directed rearward. More extensive identification characteristics can be found in " Drosophila : A Guide to Species Identification and Use" by Therese A. Markow and Patrick O'Grady, (Academic Press, 2005) ISBN   0-12-473052-3 or " Drosophila : A Laboratory Handbook" by M. Ashburner , K. Golic, S. Hawley, (Cold Spring Harbor Laboratory Press, 2005). There

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3968-457: The teneurin family is conserved from Caenorhabditis elegans ( ten-1 ) to vertebrates, in which four paralogs exist (teneurin-1 to -4 or odz-1 to -4). Their distinct protein domain architecture is highly conserved between invertebrate and vertebrate teneurins, particularly in the extracellular part. The intracellular domains of Ten-a, Ten-m/Odz and C. elegans TEN-1 are significantly different, both in size and structure, from

4032-416: Was found to be effected by sociosexual interactions , and is connected to mating-related decrease of evening activity. D. melanogaster remains one of the most studied organisms in biological research, particularly in genetics and developmental biology. It is also employed in studies of environmental mutagenesis. D. melanogaster was among the first organisms used for genetic analysis , and today it

4096-438: Was the first animal to be launched into space in 1947. As of 2017, six Nobel Prizes have been awarded to drosophilists for their work using the insect. Drosophila melanogaster is typically used in research owing to its rapid life cycle, relatively simple genetics with only four pairs of chromosomes , and large number of offspring per generation. It was originally an African species, with all non-African lineages having

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