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"Unnatural selection" redirects here. For other uses, see Unnatural Selection (disambiguation).
A Belgian Blue cow. The defect in the breed's myostatin gene is maintained through linebreeding and is responsible for its accelerated lean muscle growth.
This Chihuahua mix and Great Dane shows the wide range of dog breed sizes created using selective breeding.
Selective breeding transformed teosinte's few fruitcases (left) into modern maize's rows of exposed kernels (right).

Selective breeding (also called artificial selection) is the process by which humans breed other animals and plants for particular traits. Typically, strains that are selectively bred are domesticated, and the breeding is normally done by a professional breeder. Bred animals are known as breeds, while bred plants are known as varieties, cultigens, or cultivars. The offspring of two purebreed animals but of different breeds is called a crossbreed, and crossbred plants are called hybrids.

There are two approaches or types of artificial selection, or selective breeding. First is the traditional “breeder’s approach” in which the breeder or experimenter applies “a known amount of selection to a single phenotypic trait” by examining the chosen trait and choosing to breed only those that exhibit higher or “extreme values” of that trait. The second is called “controlled natural selection,” which is essentially natural selection in a controlled environment. In this, the breeder does not choose which individuals being tested “survive or reproduce,” as he or she could in the traditional approach. There are also “selection experiments,” which is a third approach and these are conducted in order to determine the “strength of natural selection in the wild.” However, this is more often an observational approach as opposed to an experimental approach. [1]

In animal breeding, techniques such as inbreeding, linebreeding, and outcrossing are utilized. In plant breeding, similar methods are used. Charles Darwin discussed how selective breeding had been successful in producing change over time in his book, On the Origin of Species. The first chapter of the book discusses selective breeding and domestication of such animals as pigeons, cats, cattle, and dogs. Selective breeding was used by Darwin as a springboard to introduce the theory of natural selection, and to support it.[2]

The deliberate exploitation of selective breeding to produce desired results has become very common in agriculture and experimental biology.

Selective breeding can be unintentional, e.g., resulting from the process of human cultivation; and it may also produce unintended – desirable or undesirable – results. For example, in some grains, an increase in seed size may have resulted from certain ploughing practices rather than from the intentional selection of larger seeds. Most likely, there has been an interdependence between natural and artificial factors that have resulted in plant domestication.[3]

History[edit]

Selective breeding of both plants and animals has been practiced since early prehistory; key species such as wheat, rice, and dogs have been significantly different from their wild ancestors for millennia, and maize, which required especially large changes from teosinte, its wild form, was selectively bred in Mesoamerica. Selective breeding was practiced by the Romans.[4] Treatises as much as 2,000 years old give advice on selecting animals for different purposes, and these ancient works cite still older authorities, such as Mago the Carthaginian.[5] The notion of selective breeding was later expressed by the Persian Muslim polymath Abu Rayhan Biruni in the 11th century. He noted the idea in his book titled India, and gave various examples.[6]

The agriculturist selects his corn, letting grow as much as he requires, and tearing out the remainder. The forester leaves those branches which he perceives to be excellent, whilst he cuts away all others. The bees kill those of their kind who only eat, but do not work in their beehive.

Selective breeding was established as a scientific practice by Robert Bakewell during the British Agricultural Revolution in the 18th century. Arguably, his most important breeding program was with sheep. Using native stock, he was able to quickly select for large, yet fine-boned sheep, with long, lustrous wool. The Lincoln Longwool was improved by Bakewell, and in turn the Lincoln was used to develop the subsequent breed, named the New (or Dishley) Leicester. It was hornless and had a square, meaty body with straight top lines.[7]

These sheep were exported widely, including to Australia and North America, and have contributed to numerous modern breeds, despite that fact that they fell quickly out of favor as market preferences in meat and textiles changed. Bloodlines of these original New Leicesters survive today as the English Leicester (or Leicester Longwool), which is primarily kept for wool production.

Bakewell was also the first to breed cattle to be used primarily for beef. Previously, cattle were first and foremost kept for pulling ploughs as oxen[citation needed], but he crossed long-horned heifers and a Westmoreland bull to eventually create the Dishley Longhorn. As more and more farmers followed his lead, farm animals increased dramatically in size and quality. In 1700, the average weight of a bull sold for slaughter was 370 pounds (168 kg). By 1786, that weight had more than doubled to 840 pounds (381 kg). However, after his death, the Dishley Longhorn was replaced with short-horn versions.

He also bred the Improved Black Cart horse, which later became the Shire horse.

Charles Darwin coined the term 'selective breeding'; he was interested in the process as an illustration of his proposed wider process of natural selection. Darwin noted that many domesticated animals and plants had special properties that were developed by intentional animal and plant breeding from individuals that showed desirable characteristics, and discouraging the breeding of individuals with less desirable characteristics.

Darwin used the term "artificial selection" twice in the 1859 first edition of his work On the Origin of Species, in Chapter IV: Natural Selection, and in Chapter VI: Difficulties on Theory –

Slow though the process of selection may be, if feeble man can do much by his powers of artificial selection, I can see no limit to the amount of change, to the beauty and infinite complexity of the co-adaptations between all organic beings, one with another and with their physical conditions of life, which may be effected in the long course of time by nature's power of selection.[8]

We are profoundly ignorant of the causes producing slight and unimportant variations; and we are immediately made conscious of this by reflecting on the differences in the breeds of our domesticated animals in different countries,—more especially in the less civilized countries where there has been but little artificial selection.[9]

Animal breeding[edit]

Main article: Animal breeding
Three generations of "Westies" in a village in Fife, Scotland

Animals with homogeneous appearance, behavior, and other characteristics are known as particular breeds, and they are bred through culling animals with particular traits and selecting for further breeding those with other traits. Purebred animals have a single, recognizable breed, and purebreds with recorded lineage are called pedigreed. Crossbreeds are a mix of two purebreds, whereas mixed breeds are a mix of several breeds, often unknown. Animal breeding begins with breeding stock, a group of animals used for the purpose of planned breeding. When individuals are looking to breed animals, they look for certain valuable traits in purebred stock for a certain purpose, or may intend to use some type of crossbreeding to produce a new type of stock with different, and, it is presumed, superior abilities in a given area of endeavor. For example, to breed chickens, a typical breeder intends to receive eggs, meat, and new, young birds for further reproduction. Thus, the breeder has to study different breeds and types of chickens and analyze what can be expected from a certain set of characteristics before he or she starts breeding them. Therefore, when purchasing initial breeding stock, the breeder seeks a group of birds that will most closely fit the purpose intended.

Purebred breeding aims to establish and maintain stable traits, that animals will pass to the next generation. By "breeding the best to the best," employing a certain degree of inbreeding, considerable culling, and selection for "superior" qualities, one could develop a bloodline superior in certain respects to the original base stock. Such animals can be recorded with a breed registry, the organization that maintains pedigrees and/or stud books. However, single-trait breeding, breeding for only one trait over all others, can be problematic.[10] In one case mentioned by animal behaviorist Temple Grandin, roosters bred for fast growth or heavy muscles did not know how to perform typical rooster courtship dances, which alienated the roosters from hens and led the roosters to kill the hens after reproducing with them.[10]

The observable phenomenon of hybrid vigor stands in contrast to the notion of breed purity. However, on the other hand, indiscriminate breeding of crossbred or hybrid animals may also result in degradation of quality. Studies in evolutionary physiology, behavioral genetics, and other areas of organismal biology have also made use of deliberate selective breeding, though longer generation times and greater difficulty in breeding can make such projects challenging in vertebrates.[11][12][13]

Plant breeding[edit]

Main article: Plant breeding
Researchers at the USDA have selectively bred carrots with a variety of colors.

Plant breeding has been used for thousands of years, and began with the domestication of wild plants into uniform and predictable agricultural cultigens. High-yielding varieties have been particularly important in agriculture.

Selective plant breeding is also used in research to produce transgenic animals that breed "true" (i.e., are homozygous) for artificially inserted or deleted genes.[citation needed]

Selective breeding in aquaculture[edit]

Selective breeding in aquaculture holds high potential for the genetic improvement of fish and shellfish. Unlike terrestrial livestock, the potential benefits of selective breeding in aquaculture were not realized until recently. This is because high mortality led to the selection of only a few broodstock, causing inbreeding depression, which then forced the use of wild broodstock. This was evident in selective breeding programs for growth rate, which resulted in slow growth and high mortality.[14]

Control of the reproduction cycle was one of the main reasons as it is a requisite for selective breeding programmes. Artificial reproduction was not achieved because of the difficulties in hatching or feeding some farmed species such as eel and yellowtail farming.[15] A suspected reason associated with the late realisation of success in selective breeding programs in aquaculture was the education of the concerned people – researchers, advisory personnel and fish farmers. The education of fish biologists paid less attention to quantitative genetics and breeding plans.[16]

Another was the failure of documentation of the genetic gains in successive generations. This in turn led to failure in quantifying economic benefits that successful selective breeding programs produce. Documentation of the genetic changes was considered important as they help in fine tuning further selection schemes.[14]

Quality traits in aquaculture[edit]

Aquaculture species are reared for particular traits such as growth rate, survival rate, meat quality, resistance to diseases, age at sexual maturation, fecundity, shell traits like shell size, shell colour, etc.

  • Growth rate – growth rate is normally measured as either body weight or body length. (Gjedrem 1985). This trait is of great economic importance for all aquaculture species as faster growth rate speeds up the turnover of production (Gjedrem 1983). Improved growth rates show that farmed animals utilize their feed more efficiently through a correlated response (Gjedrem 1985).
  • Survival rate – survival rate may take into account the degrees of resistance to diseases (Gjedrem 1985). This may also see the stress response as fish under stress are highly vulnerable to diseases (Gjedrem 1983). The stress fish experience could be of biological, chemical or environmental influence.
  • Meat quality – the quality of fish is of great economic importance in the market. Fish quality usually takes into account size, meatiness, and percentage of fat, colour of flesh, taste, shape of the body, ideal oil and omega-3 content (Gjedrem 1985).
  • Age at sexual maturation- The age of maturity in aquaculture species is another very important attribute for farmers as during early maturation the species divert all their energy to gonad production affecting growth and meat production and are more susceptible to health problems (Gjerde 1986).
  • Fecundity – As the fecundity in fish and shellfish is usually high it is not considered as a major trait for improvement. However, selective breeding practices may consider the size of the egg and correlate it with survival and early growth rate (Gjedrem 1985).

Finfish response to selection[edit]

Salmonids[edit]

Gjedrem (1979) showed that selection of Atlantic salmon (Salmo salar) led to an increase in body weight by 30% per generation. A comparative study on the performance of select Atlantic salmon with wild fish was conducted by AKVAFORSK Genetics Centre in Norway. The traits, for which the selection was done included growth rate, feed consumption, protein retention, energy retention, and feed conversion efficiency. Selected fish had a twice better growth rate, a 40% higher feed intake, and an increased protein and energy retention. This led to an overall 20% better Fed Conversion Efficiency as compared to the wild stock (Thodeson et al.1999). Atlantic salmon have also been selected for resistance to bacterial and viral diseases. Selection was done to check resistance to Infectious Pancreatic Necrosis Virus (IPNV). The results showed 66.6% mortality for low-resistant species whereas the high-resistant species showed 29.3% mortality compared to wild species (Storset et al. 2007).

Rainbow trout (S. gairdneri) was reported to show large improvements in growth rate after 7-10 generations of selection (Donaldson and Olson 1957). Kincaid et al. (1977) showed that growth gains by 30% could be achieved by selectively breeding rainbow trout for three generations. A 7% increase in growth was recorded per generation for rainbow trout by Kause et al. (2005). In Japan, high resistance to IPNV in rainbow trout has been achieved by selectively breeding the stock. Resistant strains were found to have an average mortality of 4.3% whereas 96.1% mortality was observed in a highly sensitive strain (Okamoto et al. 1993). Coho salmon (Oncorhynchus kisutch) increase in weight was found to be more than 60% after four generations of selective breeding (Hershberger et al. 1990). In Chile, Neira et al. (2006) conducted experiments on early spawning dates in coho salmon. After selectively breeding the fish for four generations, spawning dates were 13 – 15 days earlier.

Cyprinids

Selective breeding programs for the Common carp (Cyprinus carpio) include improvement in growth, shape and resistance to disease. Experiments carried out in the USSR used crossings of broodstocks to increase genetic diversity and then selected the species for traits like growth rate, exterior traits and viability, and/or adaptation to environmental conditions like variations in temperature. Kirpichnikov et al. (1974) and Babouchkine (1987) selected carp for fast growth and tolerance to cold, the Ropsha carp. The results showed a 30-40% to 77.4% improvement of cold tolerance but did not provide any data for growth rate. An increase in growth rate was observed in the second generation in Vietnam (Tran and Nguyen 1993). Moav and Wohlfarth (1976) showed positive results when selecting for slower growth for three generations compared to selecting for faster growth. Schaperclaus (1962) showed resistance to the dropsy disease wherein selected lines suffered low mortality (11.5%) compared to unselected (57%).

Channel Catfish[edit]

Growth was seen to increase by 12 – 20% in selectively bred Iictalurus punctatus (Bondari, 1983). More recently, the overall response of Channel Catfish response to selection for improved growth rate was found to be approximately 80%, i.e., an average of 13% per generation (Dunham 2006).

Shellfish response to selection[edit]

Oysters[edit]

Selection for live weight of Pacific oysters showed improvements ranging from 0.4% to 25.6% compared to the wild stock (Langdon et al. 2003). Sydney-rock oysters (Saccostrea commercialis) showed a 4% increase after one generation and a 15% increase after two generations (Nell et al. 1996, 1999). Chilean oysters (Ostrea chilensis), selected for improvement in live weight and shell length showed a 10-13% gain in one generation. Bonamia ostrea is a protistan parasite that causes catastrophic losses (nearly 98%) in European flat oyster Ostrea edulis L. This protistan parasite is endemic to three oyster-regions in Europe. Selective breeding programs show that O. edulis susceptibility to the infection differs across oyster strains in Europe. A study carried out by Culloty et al. (2001) showed that ‘Rossmore’ oysters in Cork harbour, Ireland had better resistance compared to other Irish strains. A selective breeding program at Cork harbour uses broodstock from 3– to 4-year-old survivors and is further controlled until a viable percentage reaches market size (Culloty et al. 2004). Over the years ‘Rossmore’ oysters have shown to develop lower prevalence to B. ostreae infection and percentage mortality. Ragone Calvo et al. (2003) selectively bred the eastern oyster, Crassostrea virginica, for resistance against co-occurring parasites Haplosporidium nelson (MSX) and Perkinsus marinus (Dermo). They achieved dual resistance to the disease in four generations of selective breeding. The oysters showed higher growth and survival rates and low susceptibility to the infections. At the end of the experiment, artificially selected C. virginica showed a 34-48% higher survival rate.

Penaeid shrimps[edit]

Selection for growth in Penaeid shrimps yielded successful results. A selective breeding program for Litopenaeus stylirostris saw an 18% increase in growth after the fourth generation and 21% growth after the fifth generation (Goyard et al. 1999). Marsupenaeus japonicas showed a 10.7% increase in growth after the first generation (Hetzel et al. 2000). Argue et al. (2002) conducted a selective breeding program on the Pacific White Shrimp, Litopenaeus vannamei at The Oceanic Institute, Waimanalo, USA from 1995 to 1998. They reported significant responses to selection compared to the unselected control shrimps. After one generation, a 21% increase was observed in growth and 18.4% increase in survival to TSV. The Taura Syndrome Virus (TSV) causes mortalities of 70% or more in shrimps. C.I. Oceanos S.A. in Colombia selected the survivors of the disease form infected ponds and used them as parents for the next generation. They achieved satisfying results in two or three generations wherein survival rates approached levels before the outbreak of the disease (Cock et al. 2009). The resulting heavy losses (up to 90%) caused by Infectious hypodermal and haematopoietic necrosis virus (IHHNV) caused a number of shrimp farming industries started to selectively breed shrimps resistant to this disease. Successful outcomes led to development of Super Shrimp, a selected line of L. stylirostris that is resistant to IHHNV infection (Tang et al. 2000). Tang et al. (2000) confirmed this by showing no mortalities in IHHNV- challenged Super Shrimp post larvae and juveniles.

Aquatic species versus terrestrial livestock[edit]

Selective breeding programs for aquatic species provide better outcomes compared to terrestrial livestock. This higher response to selection of aquatic farmed species can be attributed to the following:

  • High fecundity in both sexes fish and shellfish enabling higher selection intensity.
  • Large phenotypic and genetic variation in the selected traits.

Selective breeding in aquaculture provide remarkable economic benefits to the industry, the primary one being that it reduces production costs due to faster turnover rates. This is because of faster growth rates, decreased maintenance rates, increased energy and protein retention, and better feed efficiency (Gjedrem and Baranski 2009). Applying such genetic improvement program to aquaculture species will increase productivity to meet the increasing demands of growing populations.


Advantages and disadvantages[edit]

Selective breeding is a direct way to determine if a specific trait can “evolve in response to selection.” A single-generation method of breeding is not as accurate or direct. The process is also more practical and easier to understand than sibling analysis. The former tests “differences between line means” while the latter is dependent upon “variance and covariance components.” Essentially, selective breeding is better for traits such as physiology and behavior that are hard to measure because it requires fewer individuals to test than single-generation testing.

However, there are disadvantages to this process. Because a single experiment done in selective breeding cannot be used to assess an entire group of “genetic variances and covariances,” individual experiments must be done for every individual trait. Also, because of the necessity of selective breeding experiments to require maintaining the organisms tested in a lab or greenhouse, it is impractical to use this breeding method on many organisms. Controlled mating instances are difficult to carry out in this case and this is a necessary component of selective breeding. [1]

See also[edit]

References[edit]

  1. ^ a b Conner, Jeffrey (July 2003). "Artificial Selection: A Powerful Tool for Ecologists". Ecology 84 (7): 1650–1660. doi:10.1890/0012-9658(2003)084[1650:asaptf]2.0.co;2. JSTOR 3449986. 
  2. ^ *Darwin, Charles (2004). The Origin of Species. London: CRW Publishing Limited. ISBN 1-904633-78-1. 
  3. ^ Purugganan, Michael D.; Fuller, Dorian Q. (2009). "The nature of selection during plant domestication". Nature 457 (7231): 843–848. doi:10.1038/nature07895. PMID 19212403. Retrieved September 25, 2013. 
  4. ^ Buffum, Burt C. Arid Agriculture; A Hand-Book for the Western Farmer and Stockman, p. 232. Accessed at [1], June 20, 2010.
  5. ^ Lush, Jay L. Animal Breeding Plans, p. 21. Accessed at [2], June 20, 2010.
  6. ^ Jan Z. Wilczynski (December 1959). "On the Presumed Darwinism of Alberuni Eight Hundred Years before Darwin". Isis 50 (4): 459–466 [459–61]. doi:10.1086/348801 
  7. ^ "Robert Bakewell (1725 - 1795)". BBC History. Retrieved 20 July 2012. 
  8. ^ Darwin 1859, p. [3]
  9. ^ Darwin 1859, pp. 197–198
  10. ^ a b Grandin, Temple; Johnson, Catherine (2005). Animals in Translation. New York, New York: Scribner. pp. 69–71. ISBN 0-7432-4769-8. 
  11. ^ Swallow, JG; Garland; Jr (2005). "Selection experiments as a tool in evolutionary and comparative physiology: insights into complex traits—an introduction to the symposium" (PDF). Integr Comp Biol 45 (3): 387–390. doi:10.1093/icb/45.3.387. PMID 21676784. 
  12. ^ Garland T, Jr. (2003). Selection experiments: an under-utilized tool in biomechanics and organismal biology. Ch.3, Vertebrate Biomechanics and Evolution ed. Bels VL, Gasc JP, Casinos A. PDF
  13. ^ Garland T, Jr., Rose MR, eds. (2009). Experimental Evolution: Concepts, Methods, and Applications of Selection Experiments. University of California Press, Berkeley, California.
  14. ^ a b Gjedrem and Moranski 2009
  15. ^ Gjedrem 1985
  16. ^ Gjedrem, 1983

Sources[edit]

  • Argue, B. J.; Lotz, J. M; Moss, S.M.; Moss, Shaun M (2002). "Selective breeding of Pacific white shrimp (Litopenaeus vannamei) for growth and resistance to Taura syndrome Virus". Aquaculture 204 (3–4): 447–460. doi:10.1016/s0044-8486(01)00830-4. 
  • Babouchkine, Y.P., 1987. La sélection d’une carpe résistant à l’hiver. In: Tiews, K. (Ed.), Proceedings ofWorld Symposium on Selection,Hybridization, and Genetic Engineering in Aquaculture, Bordeaux 27–30 May 1986, vol. 1. HeenemannVerlagsgesellschaft mbH, Berlin, pp. 447–454.
  • Bondari, K. (1983). "Response to bidirectional selection for body weight in channel catfish". Aquaculture 33: 73–81. doi:10.1016/0044-8486(83)90387-3. 
  • Cock, J.; Gitterle, T.; Salazar, M; Rye, Morten (2009). "Breeding for disease resistance of Penaeid shrimps". Aquaculture 286: 1–11. doi:10.1016/j.aquaculture.2008.09.011. 
  • Culloty, S.C.; Cronin, M.A.; Mulcahy, M.F. et al. et al. (2001). "An investigation into the relative resistance of Irish flat oysters Ostrea edulis L. to the parasite Bonamia ostreae (Pichot et al., 1980)". Aquaculture 199 (3–4): 229–244. doi:10.1016/s0044-8486(01)00569-5. 
  • Culloty, S.C.; Cronin, M.A; Mulchany, M.F. (2004). "Potential resistance of a number of populations of the oyster Ostrea edulis to the parasite Bonamia ostreae". Aquaculture 237: 41–58. doi:10.1016/j.aquaculture.2004.04.007. 
  • Darwin, C (2004). The Origin of Species. London: CRW Publishing Limited. ISBN 1904633781. 
  • Donaldson, L.R.; Olson, P.R. (1957). "Development of rainbow trout broodstock by selective breeding". Transactions of the Americans Fisheries Society 85: 93–101. doi:10.1577/1548-8659(1955)85[93:dortbs]2.0.co;2. 
  • Gjerde, B (1986). "Growth and reproduction in fish and shellfish". Aquaculture 57: 37–55. doi:10.1016/0044-8486(86)90179-1. Retrieved September 25, 2013. 
  • Gjedrem, T (1979). "Selection for growth rate and domestication in Atlantic salmon". Zeitschrift für Tierzüchtung und Züchtungsbiologie 96: 56–59. doi:10.1111/j.1439-0388.1979.tb00199.x. Retrieved September 25, 2013. 
  • Gjedrem, T (1983). "Genetic variation in quantitative traits and selective Breeding in fish and shellfish". Aquaculture 33 (1–4): 51–72. doi:10.1016/0044-8486(83)90386-1. Retrieved September 25, 2013. 
  • Gjedrem, T (1985). "Improvement of Productivity through Breeding Schemes". GeoJournal 10 (3): 233–241. doi:10.1007/BF00462124. Retrieved September 25, 2013. 
  • Gjedrem, T. (1997). "Selective breeding to improve aquaculture production". World Aquaculture 28: 33–45. 
  • Gjedrem, T & Baranski, M. 2009. Selective breeding in Aquaculture: An Introduction. 1st Edition. Springer.
  • Goyard, E.; Patrois, J.; Reignon, J.-M.; Vanaa, V.; Dufour, R; Be (1999). "IFREMER's shrimp genetics program". Global Aquaculture Advocate 2 (6): 26–28. 
  • Grandin, T; Johnson, C (2005). Animals in Translation. New York: Scribner. p. 69–71. ISBN 0-7432-4769-8. 
  • Hershberger, W.K.; Myers, J.M.; Iwamoto, R.N.; Mcauley, W.C; Saxton, A.M. (1990). "Genetic Changes in the Growth of Coho Salmon (Oncorhynchus kisutch) in Marine Net-Pens, Produced by Ten Years of Selection". Aquaculture 85: 187–197. doi:10.1016/0044-8486(90)90018-i. 
  • Hetzel, D.J.S., Crocos, P.J., Davis, G.P., Moore, S.S., Preston, N.C., 2000. Response to selection and heritability for growth in the Kuruma prawn, Penaeus japonicus. Aquaculture 181, 215–223.
  • Kause, A.; Ritola, O.; Paananen, T.; Wahlroos, H; Mäntysaari, E.A. (2005). "Genetic trends in growth, sexual maturity and skeletal deformations, and rate of inbreeding in a breeding programme for rainbow trout (Oncorhynchus mykiss)". Aquaculture 247: 177–187. doi:10.1016/j.aquaculture.2005.02.023. 
  • Kincaid, H. L.; Bridges, W.R.; Von Limbach, B. (1977). "Three generations of selection for growth rate in fall-spawning rainbow trout". Transactions of the Americans Fisheries Society 106 (6): 621–628. doi:10.1577/1548-8659(1977)106<621:tgosfg>2.0.co;2. 
  • Kirpichnikov, V.S.; IIYAsov, J.I.; Shart, L.A.; Vikhman, A.A.; Ganchenko, M.V.; Ostashevsky, A.L.; Simonov, V.M.; Tikhonov, G.F; Tjurin, V.V. et al. et al. (1993). "Selection of Krasnodar common carp (Cyprinus carpio L.) for resistance to dropsy: principal results and prospects". Aquaculture 111: 7–20. doi:10.1016/b978-0-444-81527-9.50006-3. ISBN 9780444815279. 
  • Langdon, C.; Evans, F.; Jacobson, D; Blouin, M. (2003). "Yields of cultures Pacific oysters Crassostrea gigas Thunberg improved after one generation of selection". Aquaculture 220: 227–244. doi:10.1016/s0044-8486(02)00621-x. 
  • Moav, R.; Wohlfarth, G.W. (1976). "Two way selection for growth rate in the common carp (Cyprinus carpio L.)". Genetics 82 (1): 83–101. PMC 1213447. PMID 1248737. 
  • Neira, R.; Díaz, N.; Gall, G.; Gallardo, J.; Lhorente, J; Alert, A. (2006). "Genetic improvement in Coho salmon (Oncorhynchus kisutch). II: selection response for early spawning date". Aquaculture 257: 1–9. doi:10.1016/j.aquaculture.2006.03.001. 
  • Nell, J.A.; Sheridan, A.K.; Smith, I.R. (1996). "Progress in a Sydney rock oyster, Saccostrea commercialis (Iredale and Roughley), breeding program". Aquaculture 144 (4): 295–302. doi:10.1016/0044-8486(96)01328-2. 
  • Nell, J.A.; Smith, I.R.; Sheridan, A.K. (1999). "Third generation evaluation of Sydney rock oyster Saccostrea commercialis (Iredale and Roughley) breeding lines". Aquaculture 170 (3–4): 195–203. doi:10.1016/s0044-8486(98)00408-6. 
  • Okamoto, N.; Tayama, T.; Kawanobe, M.; Fujiki, N.; Yasuda, Y; Sano, T. (1993). "Resistance of a rainbow trout strain to infectious pancreatic necrosis". Aquaculture 117: 71–76. doi:10.1016/0044-8486(93)90124-h. 
  • Purugganan, Michael D.; Fuller, Dorian Q. (2009). "The nature of selection during plant domestication". Nature 457 (7231): 843–848. doi:10.1038/nature07895. PMID 19212403. 
  • Calvo, Ragone; Calvo, G.W; Burreson, E. M. (2003). "Dual disease resistance in a selectively bred eastern oyster, Crassostrea virginica, strain tested in Chesapeake Bay". Aquaculture 220: 69–87. doi:10.1016/s0044-8486(02)00399-x. 
  • Schäperclaus, W. (1962). Traité de pisciculture en étang. Paris: Vigot Frères. 
  • Storset, A; Strand, C; Wetten, M; Kjøglum, S; Ramstad, A. (2007). "Response to selection for resistance against infectious pancreatic necrosis in Atlantic salmon (Salmo salar L.)". Aquaculture 272: 62–68. 
  • Tang, K. F. J.; Durand, S. V.; White, B. L.; Redman, R. M.; Pantoja, C. R; Lightner, D.V. (2000). "Postlarvae and juveniles of a selected line of Penaeus stylirostris are resistant to infectious hypodermal and hematopoietic necrosis virus infection". Aquaculture 190 (3–4): 203–210. doi:10.1016/s0044-8486(00)00407-5. 
  • Thodeson, J.; Gisdale-Helland, B.; Helland, S.J; Gjerde, B. (1999). "Feed intake, growth and feed utilization of offspring from wild and selected Atlantic salmon (Salmo salar)". Aquaculture 180: 237–246. 
  • Tran, M.T.; Nguyen, C.T. (1993). "Selection of common carp (Cyprinus carpio L.) in Vietnam". Aquaculture 111: 301–302. doi:10.1016/0044-8486(93)90064-6. 

External links[edit]


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Super Cow Creators

These gigantic cows resemble bovine body-builders. See how breeders have achieved such amazing results. Extreme Genes: THURS FEBRUARY 21 9P et/pt : http://ch...

SciShow Talk Show - Selective Breeding & the Rat

Nick Jenkins talks with Hank Green about selective breeding, with special guest Jessi Knudsen Castañeda. Nick Jenkins: https://www.youtube.com/user/thelonely...

Mad Science: Eugenics and Selective Breeding

Human beings have tinkered with the genetic traits of animals and plants alike, placing artificial pressure on the process of natural selection. So what happ...

Selective Breeding Video

Fourth form class project by Hugh Johnson.

Genetic Engineering and Selective Breeding

This video will go over two types of genetic engineering; recombinant DNA and gene transfer. It will also discusse how selective breeding works.

Science Today: Creating the Perfect Pet | California Academy of Sciences

Artificial selection in dogs has been around for a long time-- that's what pure breeds are. But what really makes the best pet? A purebred, a mutt, or a mira...

Animal Farm Episode 1, Part 3 of 10

A programme looking at Genetic Modification and Selective breeding. Giving examples on this imaginary farm. Sorry about the quality if it goes slow in places.

Bloodline_ The Search for Speed

Bloodline is a short film that depicts historical selective breeding of horses for speed with a focus on Ireland's contribution to excellence in Thoroughbred...

Unnatural Selection Dog Breeding - RealSports

"Unnatural Selection" segment on dog breeding ethics in the USA from the 4-22-2014 Real Sports with Bryant Gumble on HBO.

74488 videos foundNext > 

4945 news items

 
TheBacklot
Tue, 25 Nov 2014 04:42:14 -0800

Thanks to selective breeding the average turkey has gone from 13lbs 80 years ago to 30lbs today. The male turkeys run closer to 50lbs, and the extra weight makes them unable to actually mate, so all the breeding is done by artificial insemination.

The Daily Meal

The Daily Meal
Mon, 24 Nov 2014 14:04:35 -0800

Nowadays, due to demand and selective breeding for an increasingly hungry population, the average bird weighs just under 30 pounds, with a large, deformed breast and stooped shoulders. Your Thanksgiving turkey likely couldn't stand upright before its ...

Slate Magazine (blog)

Slate Magazine (blog)
Fri, 21 Nov 2014 12:24:02 -0800

In October, Vox published a picture that vividly shows how much bigger chickens have gotten since 1957, thanks to selective breeding. If you've taken a gander at a gargantuan Butterball bird lately, you'll be unsurprised to learn that selective ...
 
Reuters
Sun, 23 Nov 2014 22:11:15 -0800

About Salmobreed: SalmoBreed AS is a genetics company specialising in selective breeding of Atlantic salmon, offering optimal adaptation to current and future production trends. * Source text for Eikon: Further company coverage: (Reporting By Ole ...
 
Wanganui Chronicle
Tue, 25 Nov 2014 10:00:00 -0800

Selective breeding on a trial-and-error basis may be slower than modern methods of genetic engineering but, given enough time, the result is much the same. Cats do not generally lack self-confidence and I have no doubt that the consensus among felines ...
 
Hoosier Ag Today
Sun, 23 Nov 2014 19:45:00 -0800

Scientists, including Walport and the EU chief scientist Anne Glover, say GM is not inherently dangerous and essentially no different than the selective breeding that humans have engaged in for millennia and that each crop should be assessed on its own ...

The New Indian Express

The New Indian Express
Sun, 23 Nov 2014 16:52:17 -0800

Noel Kannan, an experienced pigeon fancier, says years of selective breeding of pigeons with good bloodline and eye sign, ends in producing the best racing birds. Though the import of foreign breeds is now strictly prohibited, avid pigeon fanciers have ...

ABC News

ABC News
Sun, 23 Nov 2014 03:26:15 -0800

They found some differences, caused by genetic changes driven by humans through selective breeding programs, but the differences between cats and their wild kinfolk is not all that great, Warren said in a telephone interview. It is not nearly as great, ...
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