Selective breeding in the context of Genetic test

A cultivar is a kind of cultivated plant that people have selected for desired traits and which retains those traits when propagated. Methods used to propagate cultivars include division, root and stem cuttings, offsets, grafting, tissue culture, or carefully controlled seed production. Most cultivars arise from deliberate human manipulation, but some originate from wild plants that have distinctive characteristics. Cultivar names are chosen according to rules of the International Code of Nomenclature for Cultivated Plants (ICNCP), and not all cultivated plants qualify as cultivars. Horticulturists generally believe the word cultivar was coined as a term meaning "cultivated variety".

Popular ornamental plants like roses, camellias, daffodils, rhododendrons, and azaleas are commonly cultivars produced by breeding and selection or as sports, for floral colour or size, plant form, or other desirable characteristics. Similarly, the world's agricultural food crops are almost exclusively cultivars that have been selected for characters such as improved yield, flavour, and resistance to disease. Since the advent of genetic engineering in the 1970s and the rise of its application in crop breeding in the 1980s, very few wild plants are used as commercial food sources. Trees used in forestry are also special selections grown for their enhanced quality and yield of timber, for example American timber company Weyerhaeuser is the leading grower of genetically modified Douglas-fir trees, one of the most commonly harvested trees.

Natural selection is the differential survival and reproduction of individuals due to differences in the relative fitness endowed on them by their own particular complement of observable characteristics. It is a key law or mechanism of evolution which changes the heritable traits characteristic of a population or species over generations. Charles Darwin popularised the term "natural selection", contrasting it with artificial selection, which is intentional, whereas natural selection is not.

For Darwin natural selection was a law or principle which resulted from three different kinds of process: inheritance, including the transmission of heritable material from parent to offspring and its development (ontogeny) in the offspring; variation, which partly resulted from an organism's own agency (see phenotype; Baldwin effect); and the struggle for existence, which included both competition between organisms and cooperation or 'mutual aid' (particularly in 'social' plants and social animals).

Charles Robert Darwin (/ˈdɑːrwɪn/ DAR-win; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended from a common ancestor is now generally accepted and considered a fundamental scientific concept. In a joint presentation with Alfred Russel Wallace, he introduced his scientific theory that this branching pattern of evolution resulted from a process he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding. Darwin has been described as one of the most influential figures in human history and was honoured by burial in Westminster Abbey.

Darwin's early interest in nature led him to neglect his medical education at the University of Edinburgh; instead, he helped Grant to investigate marine invertebrates. His studies at the University of Cambridge's Christ's College from 1828 to 1831 encouraged his passion for natural science. However, it was his five-year voyage on HMS Beagle from 1831 to 1836 that truly established Darwin as an eminent geologist. The observations and theories he developed during his voyage supported Charles Lyell's concept of gradual geological change. Publication of his journal of the voyage made Darwin famous as a popular author. His first scientific work was The Structure and Distribution of Coral Reefs (1842). Along with his work on barnacles, it won him the Royal Medal in 1853.

This page gives a list of domesticated animals, also including a list of animals which are or may be currently undergoing the process of domestication and animals that have an extensive relationship with humans beyond simple predation. This includes species which are semi-domesticated, undomesticated but captive-bred on a commercial scale, or commonly wild-caught, at least occasionally captive-bred, and tameable. In order to be considered fully domesticated, most species have undergone significant genetic, behavioural and morphological changes from their wild ancestors, while others have changed very little from their wild ancestors despite hundreds or thousands of years of potential selective breeding. A number of factors determine how quickly any changes may occur in a species, but there is not always a desire to improve a species from its wild form. Domestication is a gradual process, so there is no precise moment in the history of a given species when it can be considered to have become fully domesticated.

Zooarchaeology has identified three classes of animal domesticates:

Agriculture in West Asia can be traced back to the early Neolithic in the Near East, between 10,000 and 8,000 BC, when a series of domestications by human communities took place, primarily involving a few plants (cereals and legumes) and animals (sheep, goats, bos, and pigs). In these regions, this gradually led to the introduction of agriculture and animal husbandry and their expansion to other parts of the world. The Neolithic is commonly defined as the transition from a "predatory" economy of hunter-gatherers (or "collectors") to a "productive" economy of farmer-breeders, which places the question of plant and animal domestication at the heart of the upheavals brought about by this period.

Farming and livestock breeding appeared in areas of rich biological diversity, where domesticated plants and animals were found in the wild. These regions also contain a large number of food resources in their natural state. Before their domestication, domesticated plants and animals were exploited in the form of gathering and hunting, with the methods and techniques required for domestication already known at the end of the Palaeolithic. Between 9500 and 8500 B.C., "pre-domestic" forms of agriculture were introduced; plants still had a wild character, but their reproduction was controlled by humans. Control of wild animals also began in the same period. These practices gradually led to the emergence of domesticated plant and animal species, which are distinct from the wild forms from which they derive. From a biological point of view, these domesticated species undergo a transition from natural selection to artificial selection by humans. This indicates the conclusion of the domestication process in the period between 8500 BC and 8000 BC. From this point onwards, village communities relied more on the "agro-pastoral" system, combining agriculture and animal husbandry, and less on hunting, fishing, and gathering practices.

Animal husbandry is the branch of agriculture concerned with animals that are raised for meat, fibre, milk, or other products. It includes day-to-day care, management, production, nutrition, selective breeding, and the raising of livestock. Husbandry has a long history, starting with the Neolithic Revolution when animals were first domesticated, from around 13,000 BC onwards, predating farming of the first crops. During the period of ancient societies like ancient Egypt, cattle, sheep, goats, and pigs were being raised on farms.

Major changes took place in the Columbian exchange, when Old World livestock were brought to the New World, and then in the British Agricultural Revolution of the 18th century, when livestock breeds like the Dishley Longhorn cattle and Lincoln Longwool sheep were rapidly improved by agriculturalists, such as Robert Bakewell, to yield more meat, milk, and wool. A wide range of other species, such as horse, water buffalo, llama, rabbit, and guinea pig, are used as livestock in some parts of the world. Insect farming, as well as aquaculture of fish, molluscs, and crustaceans, is widespread.

A cultigen (from Latin cultus 'cultivated' and gens 'kind'), or cultivated plant, is a plant that has been deliberately altered or selected by humans, by means of genetic modification, graft-chimaeras, plant breeding, or wild or cultivated plant selection. These plants have commercial value in horticulture, agriculture and forestry. Plants meeting this definition remain cultigens whether they are naturalised, deliberately planted in the wild, or grown in cultivation.

The dog (Canis familiaris or Canis lupus familiaris) is a domesticated descendant of the gray wolf. Also called the domestic dog, it was selectively bred from a population of wolves during the Late Pleistocene by hunter-gatherers. Dogs were the first species to be domesticated over 14,000 years ago, before the development of agriculture. Due to their long association with humans, dogs have gained the ability to thrive on a starch-rich diet that would be inadequate for other canids.

Dogs have been bred for desired behaviors, sensory capabilities, and physical attributes. Dog breeds vary widely in shape, size, and color. They have the same number of bones (with the exception of the tail), powerful jaws that house around 42 teeth, and well-developed senses of smell, hearing, and sight. Compared to humans, dogs possess a superior sense of smell and hearing, but inferior visual acuity. Dogs perform many roles for humans, such as hunting, herding, pulling loads, protection, companionship, therapy, aiding disabled people, and assisting police and the military.

Flightless birds are birds that cannot fly, as they have, through evolution, lost the ability. There are over 60 extant species, including the well-known ratites (ostriches (Struthio), emus (Dromaius), cassowaries (Casuarius), rheas, and kiwis (Apteryx)) and penguins (Sphenisciformes). The smallest flightless bird is the Inaccessible Island rail (length 12.5 cm, weight 34.7 g). The largest (both heaviest and tallest) flightless bird, which is also the largest living bird in general, is the common ostrich (2.7 m, 156 kg).

Some domesticated birds, such as the domestic chicken, have lost the ability to fly for extended periods, although their ancestral species, the red junglefowl and others, respectively, are capable of extended flight. A few particularly bred birds, such as the Broad Breasted White turkey, have become totally flightless as a result of selective breeding; the birds were bred to grow massive breast meat that weighs too much for the bird's wings to support in flight.

Animal slaughter is the killing of animals, usually referring to killing domestic livestock. It is estimated that each year, 80 billion land animals are slaughtered for food. Most animals are slaughtered for food; however, they may also be slaughtered for other reasons such as for harvesting of pelts, being diseased and unsuitable for consumption, or being surplus for maintaining a breeding stock. Slaughter typically involves some initial cutting, opening the major body cavities to remove the entrails and offal but usually leaving the carcass in one piece. Such dressing can be done by hunters in the field (field dressing of game) or in a slaughterhouse. Later, the carcass is usually butchered into smaller cuts.

The animals most commonly slaughtered for food are cattle and water buffalo, sheep, goats, pigs, deer, horses, rabbits, poultry (mainly chickens, turkeys, ducks and geese), insects (a commercial species is the house cricket), and increasingly, fish in the aquaculture industry (fish farming). In 2020, Faunalytics reported that the countries with the largest number of slaughtered cows and chickens are China, the United States, and Brazil. Concerning pigs, they are slaughtered by far the most in China, followed by the United States, Germany, Spain, Vietnam, and Brazil. For sheep, again China slaughtered the most, this time followed by Australia and New Zealand. Similarly, the amount (in tonnes) of fish used for production is highest in China, Indonesia, Peru, India, Russia, and the United States (in that order).

The domestication of vertebrates is the mutual relationship between vertebrate animals, including birds and mammals, and the humans who influence their care and reproduction.

Charles Darwin recognized a small number of traits that made domesticated species different from their wild ancestors. He was also the first to recognize the difference between conscious selective breeding (i.e. artificial selection) in which humans directly select for desirable traits, and unconscious selection where traits evolve as a by-product of natural selection or from selection of other traits. There is a genetic difference between domestic and wild populations. There is also a genetic difference between the domestication traits that researchers believe to have been essential at the early stages of domestication, and the improvement traits that have appeared since the split between wild and domestic populations. Domestication traits are generally fixed within all domesticates, and were selected during the initial episode of domestication of that animal or plant, whereas improvement traits are present only in a portion of domesticates, though they may be fixed in individual breeds or regional populations.

Meat is animal tissue, mostly muscle, that is eaten as food. Humans have hunted and farmed other animals for meat since prehistory. The Neolithic Revolution allowed the domestication of vertebrates, including chickens, sheep, goats, pigs, horses, and cattle, starting around 11,000 years ago. Since then, selective breeding has enabled farmers to produce meat with the qualities desired by producers and consumers. Meat is important to economies and cultures around the world.

Meat is mainly composed of water, protein, and fat. Its quality is affected by many factors, including the genetics, health, and nutritional status of the animal involved. Without preservation, bacteria and fungi decompose and spoil unprocessed meat within hours or days. Meat is edible raw, but it is mostly eaten cooked, such as by stewing or roasting, or processed, such as by smoking or salting.

The Longhorn or British Longhorn is a British breed of beef cattle characterised by long curving horns. It originated in northern England, in the counties of Lancashire, Westmorland and Yorkshire, and later spread to the English Midlands and to Ireland. It was originally a slow heavy draught animal; cows gave a little milk, although high in fat. In the eighteenth century Robert Bakewell applied his methods of selective breeding to these cattle, which for a short time became the predominant British breed. Both the numbers and the quality of the breed declined throughout the nineteenth century and for much of the twentieth. A breed society was formed in 1878, and a herd-book published in that year.

The Longhorn was formerly listed as "priority" on the watchlist of the Rare Breeds Survival Trust, but in 2021 was listed among the "UK native breeds".

Robert Bakewell (23 May 1725 – 1 October 1795) was an English agriculturalist, now recognized as one of the most important figures in the British Agricultural Revolution. In addition to work in agronomy, Bakewell is particularly notable as the first to implement systematic selective breeding of livestock. His advancements not only led to specific improvements in sheep, cattle and horses, but contributed to general knowledge of artificial selection.