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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 animal.
Sperm competition is the competitive process between spermatozoa of two or more different males to fertilize the same egg during sexual reproduction. Competition can occur when females have multiple potential mating partners. Greater choice and variety of mates increases a female's chance to produce more viable offspring. However, multiple mates for a female means each individual male has decreased chances of producing offspring. Sperm competition is an evolutionary pressure on males, and has led to the development of adaptations to increase males' chance of reproductive success. Sperm competition results in a sexual conflict of interest between males and females. Males have evolved several defensive tactics including: mate-guarding, mating plugs, and releasing toxic seminal substances to reduce female re-mating tendencies to cope with sperm competition. Offensive tactics of sperm competition involve direct interference by one male on the reproductive success of another male, for instance by physically removing another male's sperm prior to mating with a female. For an example, see Gryllus bimaculatus.
Genetic architecture is the underlying genetic basis of a phenotypic trait and its variational properties. Phenotypic variation for quantitative traits is, at the most basic level, the result of the segregation of alleles at quantitative trait loci (QTL). Environmental factors and other external influences can also play a role in phenotypic variation. Genetic architecture is a broad term that can be described for any given individual based on information regarding gene and allele number, the distribution of allelic and mutational effects, and patterns of pleiotropy, dominance, and epistasis.
A polygene is a member of a group of non-epistatic genes that interact additively to influence a phenotypic trait, thus contributing to multiple-gene inheritance, a type of non-Mendelian inheritance, as opposed to single-gene inheritance, which is the core notion of Mendelian inheritance. The term "monozygous" is usually used to refer to a hypothetical gene as it is often difficult to characterise the effect of an individual gene from the effects of other genes and the environment on a particular phenotype. Advances in statistical methodology and high throughput sequencing are, however, allowing researchers to locate candidate genes for the trait. In the case that such a gene is identified, it is referred to as a quantitative trait locus (QTL). These genes are generally pleiotropic as well. The genes that contribute to type 2 diabetes are thought to be mostly polygenes. In July 2016, scientists reported identifying a set of 355 genes from the last universal common ancestor (LUCA) of all organisms living on Earth.
Drosophila simulans is a species of fly closely related to D. melanogaster, belonging to the same melanogaster species subgroup. Its closest relatives are D. mauritiana and D. sechellia.
The Drosophila melanogaster species subgroup contains 9 species of flies, including the best known species Drosophila melanogaster and D. simulans. The subgroup belongs to the Drosophila melanogaster species group within the subgenus Sophophora.
The mechanisms of reproductive isolation are a collection of evolutionary mechanisms, behaviors and physiological processes critical for speciation. They prevent members of different species from producing offspring, or ensure that any offspring are sterile. These barriers maintain the integrity of a species by reducing gene flow between related species.
Sexual conflict or sexual antagonism occurs when the two sexes have conflicting optimal fitness strategies concerning reproduction, particularly over the mode and frequency of mating, potentially leading to an evolutionary arms race between males and females. In one example, males may benefit from multiple matings, while multiple matings may harm or endanger females, due to the anatomical differences of that species. Sexual conflict underlies the evolutionary distinction between male and female.
The concept of a biological species as a group of organisms capable of interbreeding to produce viable offspring dates back to at least the 18th century, although it is often associated today with Ernst Mayr. Species of the fruit-fly Drosophila are one of the most commonly used organisms in evolutionary research, and have been used to test many theories related to the evolution of species. The genus Drosophila comprises numerous species that have varying degrees of premating and postmating isolation between them. These species are useful for testing hypotheses of the reproductive mechanisms underlying speciation.
Interlocus sexual conflict is a type of sexual conflict that occurs through the interaction of a set of antagonistic alleles at two or more different loci, or the location of a gene on a chromosome, in males and females, resulting in the deviation of either or both sexes from the fitness optima for the traits. A co-evolutionary arms race is established between the sexes in which either sex evolves a set of antagonistic adaptations that is detrimental to the fitness of the other sex. The potential for reproductive success in one organism is strengthened while the fitness of the opposite sex is weakened. Interlocus sexual conflict can arise due to aspects of male–female interactions such as mating frequency, fertilization, relative parental effort, female remating behavior, and female reproductive rate.
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.
Godfrey Matthew Hewitt was a British professor and evolutionary geneticist at the University of East Anglia who was very influential in the development of the fields of molecular ecology, phylogeography, speciation and hybridisation.
Drosophila sechellia is a species of fruit fly, used in lab studies of speciation because it can mate with Drosophila simulans.
Drosophila virilis is a species of fruit fly with a worldwide distribution, and was one of 12 fruit fly genomes sequenced for a large comparative study. The males have bright red gonads that can be seen through the cuticle.
Abraham Bentsionovich Korol is a professor in the Institute of Evolution at the University of Haifa. He is a prominent Israeli geneticist and evolutionary biologist known for his work on the evolution of sex and recombination, genome mapping and the genetics of complex traits. Korol was born in Bendery city, Moldavia, then part of the Soviet Union, and immigrated to Israel in 1991. Before immigrating to Israel, Korol was appointed in 1981 as a senior researcher and was awarded the degree of Doctor of Science by the Presidium of Academy of Science USSR in 1988, and became a full professor in 1991. After immigrating to Israel in 1991, Korol has established and headed the Laboratory of Population Genetics and Computational Biology in the Institute of Evolution at the University of Haifa. He became full professor there in 1996 and served as the director of the Institute of Evolution between 2008-2013. Since 1994, Korol has filled many scholarly positions including member of the steering committee of Israeli Gene Bank; member of the Human Genome Organization; member of the European Society of Evolutionary Biology; a member of the Coordinating Committee of the International Wheat Genome Sequencing Consortium; member of the Infrastructure Steering Committee of the Israeli Ministry of Science; representative of Haifa University in the Kamea program steering committee ; member of the Advisory Committee of Absorption in Science of the Israeli Ministry of Absorption.
Reinforcement is a process of speciation where natural selection increases the reproductive isolation between two populations of species. This occurs as a result of selection acting against the production of hybrid individuals of low fitness. The idea was originally developed by Alfred Russel Wallace and is sometimes referred to as the Wallace effect. The modern concept of reinforcement originates from Theodosius Dobzhansky. He envisioned a species separated allopatrically, where during secondary contact the two populations mate, producing hybrids with lower fitness. Natural selection results from the hybrid's inability to produce viable offspring; thus members of one species who do not mate with members of the other have greater reproductive success. This favors the evolution of greater prezygotic isolation. Reinforcement is one of the few cases in which selection can favor an increase in prezygotic isolation, influencing the process of speciation directly. This aspect has been particularly appealing among evolutionary biologists.
Reinforcement is a process within speciation where natural selection increases the reproductive isolation between two populations of species by reducing the production of hybrids. Evidence for speciation by reinforcement has been gathered since the 1990s, and along with data from comparative studies and laboratory experiments, has overcome many of the objections to the theory. Differences in behavior or biology that inhibit formation of hybrid zygotes are termed prezygotic isolation. Reinforcement can be shown to be occurring by measuring the strength of prezygotic isolation in a sympatric population in comparison to an allopatric population of the same species. Comparative studies of this allow for determining large-scale patterns in nature across various taxa. Mating patterns in hybrid zones can also be used to detect reinforcement. Reproductive character displacement is seen as a result of reinforcement, so many of the cases in nature express this pattern in sympatry. Reinforcement's prevalence is unknown, but the patterns of reproductive character displacement are found across numerous taxa, and is considered to be a common occurrence in nature. Studies of reinforcement in nature often prove difficult, as alternative explanations for the detected patterns can be asserted. Nevertheless, empirical evidence exists for reinforcement occurring across various taxa and its role in precipitating speciation is conclusive.
Laboratory experiments of speciation have been conducted for all four modes of speciation: allopatric, peripatric, parapatric, and sympatric; and various other processes involving speciation: hybridization, reinforcement, founder effects, among others. Most of the experiments have been done on flies, in particular Drosophila fruit flies. However, more recent studies have tested yeasts, fungi, and even viruses.
Roger Kenneth Butlin is a British evolutionary biologist and professor at the University of Sheffield. He is known for his work on speciation. He served as Editor of Heredity from 2009 to 2012, and President of the Society for the Study of Evolution from 2013 to 2015. In 2015 he received the Darwin Wallace Medal.
References
- ↑ Ritchie MG, Butlin RK (2013). Godfrey M. Hewitt (1940-2013), President of ESEB 1999-2001. J Evol Biol 26: 691–692.
- ↑ "ESEB positions" . Retrieved 26 August 2020.
- ↑ "SSE positions" (PDF). Retrieved 26 August 2020.
- ↑ Ritchie MG, Butlin RK (2013). Godfrey M. Hewitt (1940-2013), President of ESEB 1999-2001. J Evol Biol 26: 691–692.
- ↑ "Michael G Ritchie". Google Scholar . Retrieved 25 July 2021.
- ↑ Ritchie MG (2007). Sexual Selection and Speciation. Annu Rev Ecol Evol Syst 38: 79–102.
- ↑ Butlin R, Debelle A, Kerth C, Snook RR (2012). What do we need to know about speciation? Trends Ecol Evol. 27: 27-39
- ↑ Variation in female mate preference across a grasshopper hybrid zone. J Evol Biol 4: 227–240.
- ↑ Gleason JM, Ritchie MG (2004). Do quantitative trait loci (QTL) for a courtship song difference between Drosophila simulans and D. sechellia coincide with candidate genes and intraspecific QTL? Genetics 166: 1303–1311.
- ↑ Ritchie MG, Halsey EJ, Gleason JM (1999). Drosophila song as a species-specific mating signal and the behavioural importance of Kyriacou & Hall cycles in D. melanogaster song. Anim Behav 58: 649–657.
- ↑ Veltsos P, Fang Y, Cossins AR, Snook RR, Ritchie MG (2017). Mating system manipulation and the evolution of sex-biased gene expression in Drosophila. Nat Commun 8: 2072.