Kamis, 31 Agustus 2017

domestic chicken and little chicken = induk ayam dan anak ayam

Origins



Male red junglefowl.

The domestic chicken is descended primarily from the red junglefowl (Gallus gallus) and is scientifically classified as the same species.[21] As such it can and does freely interbreed with populations of red jungle fowl.[21] Recent genetic analysis has revealed that at least the gene for yellow skin was incorporated into domestic birds through hybridization with the grey junglefowl (G. sonneratii).[22] The traditional poultry farming view is that chickens were first domesticated for cockfighting in Asia, Africa, and Europe, rather than for egg or meat production. In the last decade there have been a number of genetic studies to clarify the origins. According to one study, a single domestication event occurring in the region of modern Thailand created the modern chicken with minor transitions separating the modern breeds.[23] However, that study was later found to be based on incomplete data, and recent studies point to multiple maternal origins, with the clade found in the Americas, Europe, Middle East, and Africa, originating from the Indian subcontinent, where a large number of unique haplotypes occur.[24][25] It is postulated that the jungle fowl, known as the bamboo fowl in many Southeast Asian languages, is a special pheasant well adapted to take advantage of the large amounts of fruits that are produced during the end of the 50-year bamboo seeding cycle to boost its own reproduction.[26] In domesticating the chicken, humans took advantage of this prolific reproduction of the jungle fowl when exposed to large amounts of food.[27]



It has been claimed (based on paleoclimatic assumptions) that chickens were domesticated in Southern China in 6000 BC.[28] However, according to a recent study,[29] it is unclear whether those birds were the ancestors of chickens today. Instead, the origin could be the Harappan culture of the Indus Valley. Eventually, the chicken moved to the Tarim basin of central Asia. The chicken reached Europe (Romania, Turkey, Greece, Ukraine) about 3000 BC.[30] Introduction into Western Europe came far later, about the 1st millennium BC. Phoenicians spread chickens along the Mediterranean coasts, to Iberia. Breeding increased under the Roman Empire, and was reduced in the Middle Ages.[30] Genetic sequencing of chicken bones from archaeological sites in Europe revealed that in the High Middle Ages chickens began to consistently display both a lack of aggression and the capacity to lay eggs earlier on in the breeding season.[31]



Middle East traces of chicken go back to a little earlier than 2000 BC, in Syria; chicken went southward only in the 1st millennium BC. The chicken reached Egypt for purposes of cock fighting about 1400 BC, and became widely bred only in Ptolemaic Egypt (about 300 BC).[30] Little is known about the chicken's introduction into Africa. Three possible routes of introduction in about the early first millennium AD could have been through the Egyptian Nile Valley, the East Africa Roman-Greek or Indian trade, or from Carthage and the Berbers, across the Sahara. The earliest known remains are from Mali, Nubia, East Coast, and South Africa and date back to the middle of the first millennium AD.[30]



Domestic chicken in the Americas before Western conquest is still an ongoing discussion, but blue-egged chickens, found only in the Americas and Asia, suggest an Asian origin for early American chickens.[30]



A lack of data from Thailand, Russia, the Indian subcontinent, Southeast Asia and Sub-Saharan Africa makes it difficult to lay out a clear map of the spread of chickens in these areas; better description and genetic analysis of local breeds threatened by extinction may also help with research into this area.[30]



South America

An unusual variety of chicken that has its origins in South America is the araucana, bred in southern Chile by the Mapuche people. Araucanas, some of which are tailless and some of which have tufts of feathers around their ears, lay blue-g

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