Red Rock Fowl
Reprinted the ancient book "Three Talents Association".
Han Jianlin
Domestic chickens are the most widely distributed domestic animals in the world today, but their origin and domestication process are still subject to huge controversy. Since Darwin, this issue has received considerable attention.
Recently, Kunming Institute of Zoology, Chinese Academy of Sciences and Beijing Institute of Animal Husbandry and Veterinary Medicine, Chinese Academy of Agricultural Sciences, led by more than 30 universities and research institutes at home and abroad, with Academician Zhang Yaping, Researcher Wu Dongdong and Professor Han Jianlin as co-corresponding authors, published in the journal Cell Research For the first time, the whole genome of a large number of indigenous chicken breeds distributed in Europe, South Asia, Southeast Asia, and East Asia, and all four original chickens and five subspecies of red original chickens were determined and compared systematically. The analysis provides a new perspective on the evolution of domestic chickens and helps to understand the history of human interaction with other domesticated species (such as rice, dogs, buffalo, and domestic pigs) in this area. It points to Southwest China and Thailand. The north, Myanmar and other regions are likely to be the origin and domestication centers of domestic chickens.
This newspaper has specially appointed Professor Han Jianlin, one of the corresponding authors of the paper, to explain to readers the scientific issues concerning the origin and domestication of domestic chickens.
1 Wild ancestor of domestic chicken
Based on the study of early animal taxonomy, it is believed that wild wild fowls distributed in the tropical jungles of South Asia, Southeast Asia and southern China are the ancestors of domestic chickens. There are four species in the genus Rocket, which are red rocker, green rocker, gray rocker and Ceylon rocker. Among them, the red rock fowl is the most widely distributed and the most numerous. It lives in South Asia, Southeast Asia and my country's Yunnan Province, Guangxi Zhuang Autonomous Region and Hainan Province. There is a certain degree of morphological differences between red wild fowls in different regions. For example, red wild fowls distributed in the Malay Peninsula and Java Island, Indonesia have very bright feathers, while red wild fowls living in the southern foot of the Himalayas have more feathers. dim. Animal taxonomists further divided the red jungle fowl into five subspecies, including named subspecies, southern Yunnan subspecies, Java subspecies, Indian subspecies and Hainan subspecies. During the breeding season of each year, individual red jungle fowl roosters will be mixed into villages near the jungle to mate with local domestic hens and produce fertile offspring. Red rock fowl hens lay 6-8 eggs per litter, and as few as 4 or as many as 12 eggs. Early morphological and genetic studies have shown that the red jungle fowl may be the ancestor of domestic chickens.
2 Darwin did not propose that "Chinese chicken originates from India"
It is still confusing about when, where, and by what species domestic chickens were domesticated. Based on the description of the body shape and appearance of 13 ancient domestic chicken breeds, including the "Jiujinhuang" from China, combined with previous surveys, observations and hybrid experiments on raw chickens and domestic chickens, In 1868, Darwin explicitly denied the possibility of gray rock fowl, Ceylon rock fowl and green rock fowl as the ancestors of domestic chickens in his book "The Variation of Animals and Plants at Home." He pointed out the red plains in Malay Peninsula or India. Chickens are the closest to domestic fighting cock in terms of body size, feather color and call, and are presumably the ancestor of all domestic chicken breeds.
However, in recent years, domestic scholars have been paranoid in their descriptions when introducing Darwin's question of the source of chickens in China. Darwin mentioned in related chapters that Mr. Burch of the British Museum helped him translate some of the contents of the "Encyclopedia of China" published in 1609. Based on historical records at the time, the book mentioned that domestic chickens were created by "Western" It was introduced to eastern China about 1400 BC. After a later inspection by domestic scholars, it was found that only in the "Three Talents Association" published in 1609, there was a description of chickens as follows: "There are various kinds of chickens in Shu, Lu, Jing Yue. Yue chickens are small, Shu chickens are large, and Lu chickens are different. The older one, the old said that there are chickens in Japan and China. Chickens are things of the West, Daming was born in the East, so chickens entered them.” The “West” here obviously refers to places such as “Shu” and “Jing”, which is the western part of China; And "Da Ming was born in the East" said that it was introduced to eastern China during the "Da Ming" years (420-479 AD). It can be seen that there were obvious discrepancies in the translation of the title of the so-called "Encyclopedia of China" or related content.
Darwin then pointed out: No matter how old the time is, the Chinese believed that the Indochina Peninsula and India were the origins of domestic chickens, so the goal of finding the origin of domestic chickens should focus on Southeast Asia. It can be seen that Darwin did not explicitly mention that Chinese domestic chickens were introduced from India. On the contrary, Darwin affirmed that the domestic chicken mentioned in the "Encyclopedia of China" must be centuries earlier than India.
3 Archaeological evidence has been continuously accumulated
After entering the 20th century, archaeological evidence on domestic chicken domestication has been rapidly accumulated. This type of research helps people understand how prehistoric humans got involved in animal domestication; understand the impact of past geography, landforms, climatic conditions, and other environmental factors on human society. The impact of economic activities; the use of prehistoric animal bones can also assist in the dating of relevant remains.
The earliest and most famous archaeological evidence related to domestic chickens comes from the Mohenjo-Daro ruins located in Larkana County, Sindh Province, Pakistan, where the Indus Valley civilization that emerged in 3000 BC was unearthed here Among the 37 animal bones, domesticated chickens, zebus, river buffaloes, sheep, dogs, Indian pigs, dromedaries, Indian elephants, and horses that appeared later, indicate that the ancestors of the lower Indus Have fully mastered the skills of animal domestication and successfully used them as food, medicine and decorations. Many people believe that domestic chickens domesticated in the Indus Valley spread to Greece through Mesopotamia. After obtaining the domestic chickens, the Celts brought them to Europe and the United Kingdom in the late Iron Age.
In the late 1920s, it was suggested that Indian domestic chickens arrived in China via the northern route in 1400 BC. Based on Russia’s rumor that the Mongolian invaders brought the domestic chickens over in the 13th century, some people think that Europe The domestic chickens spread through Russia after that.
In China, the remains of relatively reliable domestic chicken sources may appear at the Dadianzi site in Chifeng City, Inner Mongolia Autonomous Region about 3,600 years ago, because the remains of domestic dogs and pigs were also found here; Chicken bones were also found in the funerary pots at the Yinxu site in Anyang City, Henan Province, about 3300 years old. Based on these relatively reliable archaeological evidence, it can be speculated that domestic chickens domesticated in the traditional habitat of the red jungle fowl in Southeast Asia arrived in northern my country through cultural exchanges 3600-3300 years ago.
4 Rapidly changing research methods bring new hope
In the second half of the last century, molecular genetics methods began to be applied to the identification and classification of domestic animal species, strains, ecotypes, and the evaluation of their genetic differentiation relationships. Among them, the genetic diversity of blood proteins (enzymes) and mitochondrial DNA Mutations were once very popular molecular markers. Foreign research on chicken blood protein (enzyme) genetic diversity began in the 1960s, and domestic research has also been carried out since the late 1970s, and many meaningful progress have been made. However, because of the stringent requirements for the freshness of samples, the relatively complicated laboratory analysis, and the extremely limited overall genetic variation, research in this area has basically stopped after entering the 21st century.
In the 1990s, the Japanese imperial heir, Prince Fumihito Akashinomiya, led a team to designate the red wild fowl subspecies and southern Yunnan subspecies of Thailand, the red wild fowls nominated subspecies of Indonesia, Java subspecies and green wild fowls, and the tin of Sri Lanka in the 1990s. A comparative analysis of the mitochondrial DNA control region variation of the blue wild fowl and the Indian gray wild fowl showed that the genetic diversity of the red wild fowl is very rich, but there is no obvious difference between the other red wild fowl subspecies except the Java subspecies ; The difference between the nominated subspecies of domestic chicken and red wild fowl is also very small. Therefore, they proposed that all domestic chicken breeds are domesticated from the mainland population of the named subspecies of red wild fowl.
After entering this century, a cooperative research team led by the Kunming Institute of Zoology, Chinese Academy of Sciences, through a comparative analysis of a larger range of genetic variation in the mitochondrial DNA control region of red jungle fowl and domestic chickens, showed that different female lines of domesticated chickens may originate from South Asia, Southeast Asia, and the vast areas of southern China have involved many domestication events.
5 The latest interpretation of whole-genome big data
Although the multi-origin theory of domestic chicken domestication based on mitochondrial genome analysis has been recognized to a certain extent, some scholars have doubts about the authenticity and classification status of the five subspecies of red wild chicken, for example, whether there are some red originals. Could the chicken subspecies be derived from the wilding of local domestic chickens?
The whole-genome DNA sequencing technology that has emerged this century and the massive amount of genetic information it can provide provides a new perspective for people to fully understand the origin and evolution of humans and the domestication process of animals and plants.
We recently published this research paper, for the first time to systematically examine the whole genomes of 863 samples including indigenous chicken breeds and all four species of wild fowl and five subspecies of red wild fowl distributed in Europe, South Asia, Southeast Asia, and East Asia. This is the largest-scale genomics study of domestic chicken domestication history and genetic remodeling under artificial selection conditions. We first discovered that there are obvious genetic differentiations between the four species of wild chickens and the five subspecies of red wild chickens. They are all independent and reliable zoological taxonomic units, not the wild chickens that some people suspect. The wild population, which laid the foundation for us to further explore which wild raw fowl population is the ancestor of domesticated domestic chickens.
By comparing the genetic relationship between domestic chickens and original chickens, we found that the main direct ancestors of domestic chickens are the southern Yunnan subspecies of red jungle fowl, which is now distributed in southwest China, northern Thailand and Myanmar, and not the red jungle fowl of other subspecies. Neglected the previous views on domestic chicken domestication in northern China and the Indus Valley. With the migration and trade activities of humans, domesticated chickens were first carried to Southeast Asia and South Asia, and then crossed with other subspecies of red wild fowls and three other three species of wild fowls distributed there. This gene penetration promotes the rapid genetic adaptation of domestic chickens to the new environment, and enriches its unique behavior, morphology and reproductive traits.
(Special thanks to Peng Minsheng and Dr. Wang Mingshan, Kunming Institute of Zoology, Chinese Academy of Sciences for their contributions to this article)