A hairless dog is a dog with a genetic disposition for hairlessness and hair loss. There are two known types of genetic hairlessness, a dominant and a recessive type. The dominant type is caused by ectodermal dysplasia as a result of a mutation in the FOXI3 autosomal gene.
92-404: Dogs with dominant genes for hairlessness can pass their attributes to their offspring in natural conditions; that is, not under the control of humans. Therefore, it is possible that, in some parts of the world, groups of hairless dogs came into existence without human intervention . Later in history, people developed these groups into recognized breeds. Worldwide recognized breeds at this time are
184-468: A 34–48% higher survival rate. 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. Marsupenaeus japonicas showed a 10.7% increase in growth after the first generation. Argue et al. (2002) conducted a selective breeding program on
276-587: A 4% increase after one generation and a 15% increase after two generations. 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
368-474: 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. 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
460-422: 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 breeder typically 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
552-479: 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
644-592: A common impurity. Tin ores are rare, as reflected in the fact there were no tin bronzes in Western Asia before 3000 BCE. The Bronze Age forms part of the three-age system for prehistoric societies. In this system, it follows the Neolithic in some areas of the world. While copper is a common ore, deposits of tin are rare in the Old World , and often had to be traded or carried considerable distances from
736-674: A much more evident Mesolithic era, lasting millennia. In Northern Europe , societies were able to live well on rich food supplies from the marshlands fostered by the warmer climate. Such conditions produced distinctive human behaviours that are preserved in the material record, such as the Maglemosian and Azilian cultures. These conditions also delayed the coming of the Neolithic until as late as 4000 BCE (6,000 BP ) in northern Europe. Remains from this period are few and far between, often limited to middens . In forested areas,
828-436: A professional breeder , while domesticated plants are known as varieties , cultigens , cultivars , or breeds. Two purebred animals of different breeds produce a crossbreed , and crossbred plants are called hybrids . Flowers, vegetables and fruit-trees may be bred by amateurs and commercial or non-commercial professionals: major crops are usually the provenance of the professionals. In animal breeding artificial selection
920-542: 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
1012-529: A selected line of L. stylirostris that is resistant to IHHNV infection. Tang et al. (2000) confirmed this by showing no mortalities in IHHNV- challenged Super Shrimp post larvae and juveniles. 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: Selective breeding in aquaculture provide remarkable economic benefits to
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#17327908550711104-654: A single room. Settlements might have a surrounding stone wall to keep domesticated animals in and hostile tribes out. Later settlements have rectangular mud-brick houses where the family lived in single or multiple rooms. Burial findings suggest an ancestor cult with preserved skulls of the dead. The Vinča culture may have created the earliest system of writing. The megalithic temple complexes of Ġgantija are notable for their gigantic structures. Although some late Eurasian Neolithic societies formed complex stratified chiefdoms or even states, states evolved in Eurasia only with
1196-696: A single source. The emergence of metallurgy may have occurred first in the Fertile Crescent , where it gave rise to the Bronze Age in the 4th millennium BCE (the traditional view), although finds from the Vinča culture in Europe have now been securely dated to slightly earlier than those of the Fertile Crescent. Timna Valley contains evidence of copper mining 7,000 years ago. The process of transition from Neolithic to Chalcolithic in
1288-410: 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
1380-439: 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. 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. This
1472-470: Is a dominant gene, hairless to hairless matings will on average produce 66.6% hairless and 33.3% coated puppies. For hairless to coated matings, there will be an average of 50%/50% coated to hairless ratio, while for coated to coated matings, all puppies will be coated. The Chinese Crested Dog's coated variety is called a "Powderpuff" and is a recognized type. The coated variety of the Xoloitzcuintle
1564-405: Is a necessary component of selective breeding. Additionally, selective breeding can lead to a variety of issues including reduction of genetic diversity or physical problems. The process of selective breeding can create physical issues for plants or animals such as dogs selectively bred for extremely small sizes dislocating their kneecaps at a much more frequent rate then other dogs. An example in
1656-800: Is also a transition period between Stone Age and Bronze Age, the Chalcolithic or Copper Age. For the prehistory of the Americas see Pre-Columbian era . The notion of "prehistory" emerged during the Enlightenment in the work of antiquarians who used the word "primitive" to describe societies that existed before written records. The word "prehistory" first appeared in English in 1836 in the Foreign Quarterly Review . The geologic time scale for pre-human time periods, and
1748-413: Is also used in research to produce transgenic animals that breed "true" (i.e., are homozygous ) for artificially inserted or deleted genes. Selective breeding in aquaculture holds high potential for the genetic improvement of fish and shellfish for the process of production. Unlike terrestrial livestock, the potential benefits of selective breeding in aquaculture were not realized until recently. This
1840-516: Is an example. In archaeology, the Iron Age refers to the advent of ferrous metallurgy . The adoption of iron coincided with other changes, often including more sophisticated agricultural practices, religious beliefs and artistic styles, which makes the archaeological Iron Age coincide with the " Axial Age " in the history of philosophy. Although iron ore is common, the metalworking techniques necessary to use iron are different from those needed for
1932-488: Is anonymous. Because of this, reference terms that prehistorians use, such as " Neanderthal " or " Iron Age ", are modern labels with definitions sometimes subject to debate. The concept of a "Stone Age" is found useful in the archaeology of most of the world, although in the archaeology of the Americas it is called by different names and begins with a Lithic stage , or sometimes Paleo-Indian . The sub-divisions described below are used for Eurasia, and not consistently across
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#17327908550712024-457: Is because a single experiment done in selective breeding cannot be used to assess an entire group of genetic variances, individual experiments must be done for every individual trait. Also, due to 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
2116-409: 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. Control of the reproduction cycle was one of the main reasons as it is a requisite for selective breeding programs. Artificial reproduction
2208-782: Is called the Lower Paleolithic (as in excavations it appears underneath the Upper Paleolithic), beginning with the earliest stone tools dated to around 3.3 million years ago at the Lomekwi site in Kenya. These tools predate the genus Homo and were probably used by Kenyanthropus . Evidence of control of fire by early hominins during the Lower Palaeolithic Era is uncertain and has at best limited scholarly support. The most widely accepted claim
2300-458: Is not uncommon for fish to escape the nets or pens that they are kept in, especially in mass. If these fish are farmed in areas they are not native to they may be able to establish themselves and outcompete native populations of fish, and cause ecological harm as an invasive species. Furthermore, if they are in areas where the fish being farmed are native too their genetics are selectively bred rather than being wild. These farmed fish could breed with
2392-537: Is often combined with techniques such as inbreeding , linebreeding , and outcrossing . In plant breeding , similar methods are used. Charles Darwin discussed how selective breeding had been successful in producing change over time in his 1859 book, On the Origin of Species . Its first chapter discusses selective breeding and domestication of such animals as pigeons , cats , cattle , and dogs . Darwin used artificial selection as an analogy to propose and explain
2484-558: Is provided by a wide variety of natural and social sciences, such as anthropology , archaeology , archaeoastronomy , comparative linguistics , biology , geology , molecular genetics , paleontology , palynology , physical anthropology , and many others. Human prehistory differs from history not only in terms of its chronology , but in the way it deals with the activities of archaeological cultures rather than named nations or individuals . Restricted to material processes, remains, and artefacts rather than written records, prehistory
2576-741: Is recognized as a valid type for conformation showing with some registries, including the AKC. Coated varieties of the other breeds may or may not be recognized as valid varieties for conformation showing , depending on the breed and show or registry organization. Selective breeding Selective breeding (also called artificial selection ) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant males and females will sexually reproduce and have offspring together. Domesticated animals are known as breeds , normally bred by
2668-551: Is seen as a transition period between the Stone Age and Bronze Age. An archaeological site in Serbia contains the oldest securely dated evidence of copper making at high temperature, from 7,500 years ago. The find in 2010 extends the known record of copper smelting by about 800 years, and suggests that copper smelting may have been invented independently in separate parts of Asia and Europe at that time, rather than spreading from
2760-500: Is that H. erectus or H. ergaster made fires between 790,000 and 690,000 BP in a site at Bnot Ya'akov Bridge , Israel . The use of fire enabled early humans to cook food, provide warmth, have a light source, deter animals at night and meditate. Early Homo sapiens originated some 300,000 years ago, ushering in the Middle Palaeolithic . Anatomic changes indicating modern language capacity also arise during
2852-516: Is when the first signs of human presence have been found; however, Africa and Asia contain sites dated as early as c. 2.5 and 1.8 million years ago, respectively. Depending on the date when relevant records become a useful academic resource, its end date also varies. For example, in Egypt it is generally accepted that prehistory ended around 3100 BCE, whereas in New Guinea
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2944-867: The Chinese Crested Dog , the Xoloitzcuintle (Mexican Hairless Dog), the Peruvian Inca Orchid . The Argentine Pila , the Hairless Khala from Bolivia, and the Ecuadorian Hairless Dog are not registered hairless dog breeds. Other breeds that were said to have existed in the past were the African hairless dog (also known as the Abyssinian sand terrier, Egyptian hairless dog and African elephant dog,
3036-708: The Copper Age or Bronze Age ; or, in some geographical regions, in the Iron Age ). The term Neolithic is commonly used in the Old World ; its application to cultures in the Americas and Oceania is complicated by the fact standard progression from stone to metal tools, as seen in the Old World, does not neatly apply. Early Neolithic farming was limited to a narrow range of plants, both wild and domesticated, which included einkorn wheat , millet and spelt , and
3128-600: 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 , 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,
3220-531: The Paleolithic , by the Neolithic only Homo sapiens sapiens remained. This was a period of technological and social developments which established most of the basic elements of historical cultures, such as the domestication of crops and animals , and the establishment of permanent settlements and early chiefdoms. The era commenced with the beginning of farming , which produced the " Neolithic Revolution ". It ended when metal tools became widespread (in
3312-547: The Southern Corn leaf-blight epidemic of 1970 that wiped out 15% of the United States corn crop due to the wide use of a type of Texan corn strain that was artificially selected due to having sterile pollen to make farming easier. At the same time it was more vulnerable to Southern Corn leaf-blight. Prehistory Prehistory , also called pre-literary history , is the period of human history between
3404-606: The three-age system for human prehistory, were systematised during the nineteenth century in the work of British, French, German, and Scandinavian anthropologists , archaeologists , and antiquarians . The main source of information for prehistory is archaeology (a branch of anthropology), but some scholars are beginning to make more use of evidence from the natural and social sciences. The primary researchers into human prehistory are archaeologists and physical anthropologists who use excavation, geologic and geographic surveys, and other scientific analysis to reveal and interpret
3496-475: The "Chalcolithic", "Eneolithic", or "Copper Age" refers to a transitional period where early copper metallurgy appeared alongside the widespread use of stone tools. During this period, some weapons and tools were made of copper. This period was still largely Neolithic in character. It is a phase of the Bronze Age before it was discovered that adding tin to copper formed the harder bronze . The Copper Age
3588-632: 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
3680-623: The 19th century. The end of prehistory therefore came at different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age , Sumer in Mesopotamia , the Indus Valley Civilisation , and ancient Egypt were the first civilizations to develop their own scripts and keep historical records, with their neighbours following. Most other civilizations reached their end of prehistory during
3772-623: The Americas, these areas did not develop complex writing systems before the arrival of Eurasians, so their prehistory reaches into relatively recent periods; for example, 1788 is usually taken as the end of the prehistory of Australia . The period when a culture is written about by others, but has not developed its own writing system, is often known as the protohistory of the culture. By definition, there are no written records from human prehistory, which can only be known from material archaeological and anthropological evidence: prehistoric materials and human remains. These were at first understood by
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3864-705: The Azilian cultures, before spreading to Europe through the Iberomaurusian culture of Northern Africa and the Kebaran culture of the Levant . However, independent discovery is not ruled out. "Neolithic" means "New Stone Age", from about 10,200 BCE in some parts of the Middle East, but later in other parts of the world, and ended between 4,500 and 2,000 BCE. Although there were several species of humans during
3956-460: The Iron Age, often through conquest by empires, which continued to expand during this period. For example, in most of Europe conquest by the Roman Empire means the term Iron Age is replaced by "Roman", " Gallo-Roman ", and similar terms after the conquest. Even before conquest, many areas began to have a protohistory, as they were written about by literate cultures; the protohistory of Ireland
4048-694: The Middle East is characterized in archaeological stone tool assemblages by a decline in high quality raw material procurement and use. North Africa and the Nile Valley imported its iron technology from the Near East and followed the Near Eastern course of Bronze Age and Iron Age development. The Bronze Age is the earliest period in which some civilizations reached the end of prehistory, by introducing written records. The Bronze Age, or parts thereof, are thus considered to be part of prehistory only for
4140-739: The Middle Palaeolithic. During the Middle Palaeolithic Era, there is the first definitive evidence of human use of fire. Sites in Zambia have charred logs, charcoal and carbonized plants, that have been dated to 180,000 BP. The systematic burial of the dead , music , prehistoric art , and the use of increasingly sophisticated multi-part tools are highlights of the Middle Paleolithic. The Upper Paleolithic extends from 50,000 and 12,000 years ago, with
4232-449: The New (or Dishley) Leicester. It was hornless and had a square, meaty body with straight top lines. These sheep were exported widely, including to Australia and North America , and have contributed to numerous modern breeds, despite the 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
4324-545: 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
4416-615: 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. 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%). Growth
4508-590: 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
4600-427: The book Botany of Desire where Michael Pollan shows the connection between basic human desires through four different plants: apples for sweetness, tulips for beauty, cannabis for intoxication, and potatoes for control. In a form of reciprocal evolution humans have influenced these plants as much as the plants have influenced the people that consume them, is known as coevolution . Selective plant breeding
4692-569: The case of Indigenous Australian "highways" known as songlines . The Mesolithic, or Middle Stone Age (from the Greek mesos , 'middle', and lithos , 'stone'), was a period in the development of human technology between the Palaeolithic and Neolithic . The Mesolithic period began with the retreat of glaciers at the end of the Pleistocene epoch, some 10,000 BP, and ended with
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#17327908550714784-463: The collection of folklore and by analogy with pre-literate societies observed in modern times. The key step to understanding prehistoric evidence is dating, and reliable dating techniques have developed steadily since the nineteenth century. The most common of these dating techniques is radiocarbon dating . Further evidence has come from the reconstruction of ancient spoken languages . More recent techniques include forensic chemical analysis to reveal
4876-438: The domestication of wild plants into uniform and predictable agricultural cultigens . These high-yielding varieties have been particularly important in agriculture. As crops improved, humans were able to move from hunter-gatherer style living to a mix of hunter-gatherer and agriculture practices. Although these higher yielding plants were derived from an extremely primitive version of plant breeding, this form of agriculture
4968-409: 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
5060-506: The end of the Bronze Age large states, whose armies imposed themselves on people with a different culture, and are often called empires, had arisen in Egypt, China, Anatolia (the Hittites ), and Mesopotamia , all of them literate. The Iron Age is not part of prehistory for all civilizations who had introduced written records during the Bronze Age. Most remaining civilizations did so during
5152-639: The end of the prehistoric era is set much more recently, in the 1870s, when the Russian anthropologist Nicholai Miklukho-Maklai spent several years living among native peoples, and described their way of life in a comprehensive treatise. In Europe the relatively well-documented classical cultures of Ancient Greece and Ancient Rome had neighbouring cultures, including the Celts and the Etruscans , with little writing. Historians debate how much weight to give to
5244-446: The few mines, stimulating the creation of extensive trading routes. In many areas as far apart as China and England, the valuable new material was used for weapons, but for a long time apparently not available for agricultural tools. Much of it seems to have been hoarded by social elites, and sometimes deposited in extravagant quantities, from Chinese ritual bronzes and Indian copper hoards , to European hoards of unused axe-heads. By
5336-448: The first known use of stone tools by hominins c. 3.3 million years ago and the beginning of recorded history with the invention of writing systems . The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared c. 5,200 years ago. It took thousands of years for writing systems to be widely adopted, with writing having spread to almost all cultures by
5428-493: The first organized settlements and blossoming of artistic work. Throughout the Palaeolithic, humans generally lived as nomadic hunter-gatherers . Hunter-gatherer societies tended to be very small and egalitarian, although hunter-gatherer societies with abundant resources or advanced food-storage techniques sometimes developed sedentary lifestyles with complex social structures such as chiefdoms, and social stratification . Long-distance contacts may have been established, as in
5520-497: The first signs of deforestation have been found, although this would only begin in earnest during the Neolithic, when more space was needed for agriculture . The Mesolithic is characterized in most areas by small composite flint tools: microliths and microburins . Fishing tackle , stone adzes , and wooden objects such as canoes and bows have been found at some sites. These technologies first occur in Africa, associated with
5612-694: 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,
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#17327908550715704-461: The following Iron Age . The three-age division of prehistory into Stone Age , Bronze Age , and Iron Age remains in use for much of Eurasia and North Africa , but is not generally used in those parts of the world where the working of hard metals arrived abruptly from contact with Eurasian cultures, such as Oceania , Australasia , much of Sub-Saharan Africa , and parts of the Americas . With some exceptions in pre-Columbian civilizations in
5796-400: The idea in his book titled India , which included various examples. 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
5888-411: The idea of "farmers" experimenting with agriculture. In addition, the ability for humans to stay within one place for food and create permanent settlements made the process move along faster. During this transitional period, crops began to acclimate and evolve with humans encouraging humans to invest further into crops. Over time this reliance on plant breeding has created problems, as highlighted by
5980-452: The increasing demands of growing populations. Conversely, selective breeding within aquaculture can create problems within the biodiversity of both stock and wild fish, which can hurt the industry down the road. Although there is great potential to improve aquaculture due to the current lack of domestication, it is essential that the genetic diversity of the fish are preserved through proper genetic management, as we domesticate these species. It
6072-491: The industry, the primary one being that it reduces production costs due to faster turnover rates. When selective breeding is carried out, some characteristics are lost for others that may suit a specific environment or situation. This is because of faster growth rates, decreased maintenance rates, increased energy and protein retention, and better feed efficiency. Applying genetic improvement programs to aquaculture species will increase their productivity. Thus allowing them to meet
6164-593: The infection differs across oyster strains in Europe. A study carried out by Culloty et al. 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. Over the years 'Rossmore' oysters have shown to develop lower prevalence of B. ostreae infection and percentage mortality. Ragone Calvo et al. (2003) selectively bred
6256-473: The intentional selection of larger seeds. Most likely, there has been an interdependence between natural and artificial factors that have resulted in plant domestication. 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,
6348-473: The introduction of agriculture , the date of which varied by geographic region. In some areas, such as the Near East , agriculture was already underway by the end of the Pleistocene , and there the Mesolithic is short and poorly defined. In areas with limited glacial impact, the term " Epipalaeolithic " is preferred. Regions that experienced greater environmental effects as the last ice age ended have
6440-474: The keeping of dogs , sheep , and goats . By about 6,900–6,400 BCE, it included domesticated cattle and pigs, the establishment of permanently or seasonally inhabited settlements, and the use of pottery . The Neolithic period saw the development of early villages , agriculture , animal domestication , tools , and the onset of the earliest recorded incidents of warfare. Settlements became more permanent, some with circular houses made of mudbrick with
6532-494: The last being a reference to its grey skin) and the Siamese Hairless Dog. This type of genetic structure is said to be homozygous pre-natal lethal for the dominant gene. This means that zygotes with two dominant genes cannot live. Therefore, all dominant-hairless dogs have a heterozygous gene structure. This allows a homozygous recessive type to persist, which is the coated variety. For dogs where hairlessness
6624-663: The long course of time by nature's power of selection. 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. Animals with homogeneous appearance, behavior, and other characteristics are known as particular breeds or pure breeds, and they are bred through culling animals with particular traits and selecting for further breeding those with other traits. Purebred animals have
6716-409: The natives which could be problematic In the sense that they would have been bred for consumption rather than by chance. Resulting in an overall decrease in genetic diversity and rendering local fish populations less fit for survival. If proper management is not taking place then the economic benefits and the diversity of the fish species will falter. Selective breeding is a direct way to determine if
6808-401: The nature and behavior of pre-literate and non-literate peoples. Human population geneticists and historical linguists are also providing valuable insight. Cultural anthropologists help provide context for societal interactions, by which objects of human origin pass among people, allowing an analysis of any article that arises in a human prehistoric context. Therefore, data about prehistory
6900-511: 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
6992-552: The plant world is the Lenape potatoes were selectively bred for their disease or pest resistance which was attributed to their high levels of toxic glycoalkaloid solanine which are usually present only in small amounts in potatoes fit for human consumption. When genetic diversity is lost it can also allow for populations to lack genetic alternatives to adapt to events. This becomes an issue of biodiversity, because attributes are so wide-spread they can result in mass epidemics. As seen in
7084-420: 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
7176-658: The regions and civilizations who developed a system of keeping written records during later periods. The invention of writing coincides in some areas with the beginnings of the Bronze Age. After the appearance of writing, people started creating texts including written records of administrative matters. The Bronze Age refers to a period in human cultural development when the most advanced metalworking (at least in systematic and widespread use) included techniques for smelting copper and tin from naturally occurring outcroppings of ores, and then combining them to cast bronze . These naturally occurring ores typically included arsenic as
7268-502: The rise of metallurgy, and most Neolithic societies on the whole were relatively simple and egalitarian. Most clothing appears to have been made of animal skins, as indicated by finds of large numbers of bone and antler pins which are ideal for fastening leather. Wool cloth and linen might have become available during the later Neolithic, as suggested by finds of perforated stones that (depending on size) may have served as spindle whorls or loom weights. In Old World archaeology,
7360-887: The roosters from hens and led the roosters to kill the hens after mating with them. A Soviet attempt to breed lab rats with higher intelligence led to cases of neurosis severe enough to make the animals incapable of any problem solving unless drugs like phenazepam were used. 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 these projects challenging in such vertebrates as house mice . The process of plant breeding has been used for thousands of years, and began with
7452-635: The sometimes biased accounts in Greek and Roman literature, of these protohistoric cultures. In dividing up human prehistory in Eurasia, historians typically use the three-age system, whereas scholars of pre-human time periods typically use the well-defined geologic record and its internationally defined stratum base within the geologic time scale . The three-age system is the periodization of human prehistory into three consecutive time periods , named for their predominant tool-making technologies: Stone Age , Bronze Age and Iron Age . In some areas, there
7544-515: The survivors of the disease from 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. 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,
7636-568: The theory of natural selection but distinguished the latter from the former as a separate process that is non-directed. The deliberate exploitation of selective breeding to produce desired results has become very common in agriculture and experimental biology. Selective breeding can be unintentional, for example, 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
7728-587: The use and provenance of materials, and genetic analysis of bones to determine kinship and physical characteristics of prehistoric peoples. The beginning of prehistory is normally taken to be marked by human-like beings appearing on Earth. The date marking its end is typically defined as the advent of the contemporary written historical record. Both dates consequently vary widely from region to region. For example, in European regions, prehistory cannot begin before c. 1.3 million years ago, which
7820-460: The whole area. "Palaeolithic" means "Old Stone Age", and begins with the first use of stone tools . The Paleolithic is the earliest period of the Stone Age . It extends from the earliest known use of stone tools by hominins c. 3.3 million years ago, to the end of the Pleistocene c. 11,650 BP (before the present period). The early part of the Palaeolithic
7912-621: The wild stock. 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. Rainbow trout ( S. gairdneri ) was reported to show large improvements in growth rate after 7–10 generations of selection. 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
8004-417: Was an investment that the people who grew them were planting then could have a more varied diet. This meant that they did not completely stop their hunting and gathering immediately but instead over time transition and ultimately favored agriculture. Originally this was due to humans not wanting to risk using all their time and resources for their crops just to fail. Which was promptly called play farming due to
8096-440: Was not achieved because of the difficulties in hatching or feeding some farmed species such as eel and yellowtail farming. A suspected reason associated with the late realization 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. Another
8188-564: 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. Coho salmon ( Oncorhynchus kisutch ) increase in weight was found to be more than 60% after four generations of selective breeding. In Chile, Neira et al. (2006) conducted experiments on early spawning dates in coho salmon. After selectively breeding
8280-485: Was seen to increase by 12–20% in selectively bred Iictalurus punctatus . More recently, the response of the Channel Catfish to selection for improved growth rate was found to be approximately 80%, that is, an average of 13% per generation. Selection for live weight of Pacific oysters showed improvements ranging from 0.4% to 25.6% compared to the wild stock. Sydney-rock oysters ( Saccostrea commercialis ) showed
8372-646: Was selectively bred in Mesoamerica . Selective breeding was practiced by the Romans . 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 . The notion of selective breeding was later expressed by the Persian Muslim polymath Abu Rayhan Biruni in the 11th century. He noted
8464-680: 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. 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 color, etc. 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
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