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本帖最后由 癯鹤 于 2018-6-27 10:07 编辑

中国南方瘤牛?看来我国远古先民至少驯化了牦牛、瘤牛、水牛三种牛类,数量也不算少嘛!最好有古动物遗骸DNA研究,看看到底是哪一块的!我一直感觉,其实有些驯化物种可能因为自然灾害重新野化(比如普氏野马)或品种替换(比如圣水牛)或利用过度(比如角端牛)而灭绝。检测古代动物遗存,不一定只有与今天家畜家禽基因接近才算驯化,就好比尼安德特、丹尼索瓦,并非猿类而是灭绝人种罢了。
话说十多年前,保定修建军校广场,从地面往下挖了将近十米(修地下城),我过去玩,看到挖出来一些沙子,然后看挖出来的剖面,明显可见离地面几米的地方有很厚的河沙层,证明以前可能是河道。在挖出来的沙子堆里,我捡到很多骨头(有些可能已经是半化石状态),有一块大于手掌,很可能是牛的下颌骨。我不是专业人士,想找人鉴定,就给了一位生物学院的同学,不过好像她也不很关心,大概也没研究这个的。


我国科学家首次证明:中国黄牛有3个不同血统来源
我国科学家首次证明:中国黄牛有3个不同血统来源
2018年06月26日 17:17新华社
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  原标题:(科技)我国科学家首次证明:中国黄牛有3个不同的血统来源
  新华社西安6月26日电(记者陈晨、姜辰蓉)中国的黄牛是从哪里来的?记者26日从西北农林科技大学获悉,来自我国多家科研单位的科学家研究表明,中国黄牛有3个血统来源,即东亚普通牛、欧亚普通牛及中国南方瘤牛。这一研究将为我国肉牛新品种培育提供理论基础。
  该研究由西北农林科技大学姜雨教授团队与雷初朝教授团队合作完成,相关研究成果于2018年6月14日在《自然-通讯》在线发表。合作单位包括陕西省考古研究院、西北工业大学、云南大学、宁夏大学等。
  将野牛驯化为家牛,是新石器时代的标志性事件之一。通过提供肉、皮、役力等,牛成为了东亚农业社会中最重要的家畜。在学术界,家牛的驯化以及中国黄牛形成的复杂历史,一直是被不断深入研究的话题。
  姜雨介绍说,该研究对我国22个代表性地方品种的111头黄牛和陕西石峁遗址4000年前的8个古代黄牛样品进行了全基因组重测序,同时下载比较了国外27个牛种的149个个体的全基因组数据。论文首次证明,全世界家牛至少可以分为5个明显不同的类群,即欧洲普通牛、欧亚普通牛、东亚普通牛、中国南方瘤牛和印度瘤牛。
  “中国黄牛地方品种来源于其中的3个血统,分别为约4000年前就到达中国北方地区,目前以纯系仅在青藏高原和东北地区存在的东亚普通牛;可能在1000年前进入中国北方,以蒙古牛和哈萨克牛为代表的欧亚普通牛;以及论文新报道的与印度瘤牛早在4万年前就分离,具体来源和传播历史仍然未知的中国南方瘤牛。”雷初朝说。
  论文研究还发现,通过历史上的跨物种人工杂交选育,中国南方瘤牛和青藏高原的普通牛平均每个个体,分别被导入了其近缘物种爪哇野牛2.9%和牦牛1.2%的血统,从而使得迁徙到中国南方和青藏高原的黄牛各自提高了对所在环境的适应性。
  专家表示,这一对中国黄牛遗传特性来源系统全面的分析,将为我国兼顾高产、优质和抗逆的肉牛新品种培育提供理论基础。(完)
责任编辑:张迪
http://blog.sina.com.cn/aganmu;安德(嗨,前一个无辜被封):
http://blog.sina.com.cn/kilarler
可爱的拉比们!让我怀念我曾饲养过的嘎不捩癫——一只可爱的宠物兔!
兔子是人类饲养导致了大脑缩小。人类驯化使它们不用担心天敌、饮食,所以这些大脑部件就萎缩了,用进废退么?符合拉马克、达尔文主义呀!同理,晚期智人很多脑容量超大,而国外又有研究发现人类的大脑进入全新世以来一直在萎缩,说明文化和文明进步同样保证了人们减少了很多原始人必须的生存需要负担,旦复旦兮,人们的大脑就越来越猥琐了,这也是人类自我驯化的明证。而且,枪虾蚂蚁蜜蜂裸鼹鼠体现了自然社会和思维发展的一般规律,社会化程度越高,单个需要用到脑子的几率就越少,到了工厂主义只需要流水化作业机器人操作喽!不用动脑就能实现物质财富的极大丰富,还真正解放了人类身体(难怪当今社会脱贫致富慨而慷,只让那些小学毕业的乐呵呵享受卖家卖地呐的尊荣,让我等为住权忧心为学问殚精竭虑者惶惶不可终日)!

Pet rabbits are less afraid of people because their brains have SHRUNK and reshaped thanks to domestication
  • Scientists in Sweden raised domestic and wild rabbits in similar conditions
  • They used MRI scanners to study how domestication affected their brains
  • The amygdala, the area that senses fear, was smaller in domestic rabbits
  • The medial prefrontal cortex, which controls response to fear, was bigger
  • Pet rabbits also had less white matter, which makes them slower to react
By Tim Collins For Mailonline
Published: 17:45 BST, 26 June 2018 | Updated: 18:58 BST, 26 June 2018
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Domesticating rabbits has changed the structure of their brains so that they process fear completely differently to wild ones, scientists have shown.
Pet bunnies are less afraid of contact with humans, thanks to 'profound' differences in their brains, revealed by advanced imaging scans.
Alterations were found in regions involved in their response to fear, the amygdala and medial prefrontal cortex.
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Domesticating rabbits has changed the structure of their brains so that they process fear completely differently to wild ones. This Illustration shows differences in the amygdala (orange) and medial prefrontal cortex (blue) between domestic (right) and wild rabbits (left)

Scientists at Uppsalla University in Sweden raised domestic and wild rabbits in similar conditions and used high-resolution MRI scanners to study how domestication affected their brains.
The results showed that domestication has had a major effect, with the amygdala, the area that senses fear, smaller in domestic rabbits.
The part of the brain that controls the animal's response to that fear, the medial prefrontal cortex, was found to be bigger.
Pet rabbits also had less white matter, which limits their information processing abilities, making them slower to react.

In contrast to domestic rabbits, wild rabbits have a very strong flight response.
Due to their history of being are hunted by eagles, hawks, foxes and humans, they must remain alert and reactive to survive in the wild.
One of the paper's leading authors, Dr Miguel Carneiro, said: 'In a previous study we reported that genetic differences between wild and domestic rabbits are particularly common in the vicinity of genes expressed during brain development.
'In the present study we decided to use high-resolution MRI to explore if these genetic changes are associated with changes in brain morphology.'

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Scientists at Uppsalla University in Sweden raised domestic and wild rabbits in similar conditions and used high-resolution MRI scanners to study how domestication affected their brains (pictured)


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The results showed that domestication has had a major effect, with the amygdala, the area that senses fear, smaller in domestic rabbits as shown by this diagram

Lead researcher and PhD student Irene Brusini added: 'We observed three profound differences between the brains of wild and domestic rabbits.
'Firstly, wild rabbits have a larger brain-to-body size ratio than domestic rabbits.
'Secondly, domestic rabbits have a reduced amygdala and an enlarged medial prefrontal cortex.
'Thirdly, we noticed a generalised reduction in white matter structure in domestic rabbits.'
The full findings of the study were published in the journal PNAS.

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Domestication is nothing new as this 1530 painting, Madonna of the rabbit, painted by Tiziano Vecellio shows. It was selected by researchers to illustrate a domestic rabbit from the 16th century with altered coat colour and behaviour compared with a wild rabbit
http://blog.sina.com.cn/aganmu;安德(嗨,前一个无辜被封):
http://blog.sina.com.cn/kilarler
蒙古国出土的马骨,说明至少在商周之际那里的人们已经会给马做牙科手术,并很可能会骑马了。这大概也是探究骑马术的起源的重要考古证据。







Oldest evidence of animal dentistry is unearthed in Mongolian horse remains, proving vets have been relieving pain for over 3,000 years

  • The horses belonged to the ancient Deer Stone-Khirigsuur Culture
  • They roamed the steppes of Mongolia between 1300 to 700 BC
  • Researchers found people were using dental procedures to remove baby teeth
  • They would have caused young horses pain or difficulty with feeding

ByPhoebe Weston For Mailonline

Published: 20:00 BST, 2 July 2018 | Updated: 20:00 BST, 2 July 2018
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Humans have been removing horses' teeth to relieve their pain more than 3,000 years ago, according to scientists.
Equine skeletons found in Mongolia have revealed that ancient dentistry was being practised more than a millennium earlier than previously thought.
The horses belonged to an ancient Mongolian pastoral culture known as the Deer Stone-Khirigsuur Culture, which roamed the steppes of Mongolia and eastern Eurasia between 1300 to 700 BC.
It was the innovation of a nomadic tribe of peaceful horsemen that later spawned notorious warlord Genghis Khan and his Mongol hordes about two millennia later.
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Humans were removing horses' teeth to relieve their pain more than 3,000 years ago, according to scientists. Horses (pictured) congregate near a deer stone site in Bayankhongor, in central Mongolia's Khangai Mountains

The Deer Stone-Khirigsuur Culture is named after the beautiful carved standing stones ('deer stones') and burial mounds (khirigsuurs) it built across the Mongolian Steppe.
The sites were used for ritual burial of hundreds – or even thousands – of domestic horses by the pastoral land farmers.
Skeletons were dug up from beneath the stones and mounds by researchers from the Max Planck Institute for the Science of Human History.
Through careful analysis they found people were using veterinary dental procedures to remove baby teeth that would have caused young horses pain or difficulty with feeding.



'These results show a careful understanding of horse anatomy and a tradition of care was first developed - not in the sedentary civilisations of China or the Mediterranean - but centuries earlier among the nomadic people whose livelihood depended on the well-being of their horses', said lead researcher Dr William Taylor.



Previous research has discovered these early herders were the first in eastern Eurasia to rely heavily on horses as livestock for food products.
They could also have been among the first to use horses for mounted riding, according to the study published in the Proceedings of the National Academy of Sciences.

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Pictured is a horse skull placed next to a deer stone in central Mongolia. Horse skulls are revered by modern herders, as are deer stones – this one has been decorated with a ceremonial blue prayer scarf

WHAT IS THE DEER STONE-KHIRIGSUUR CULTURE? The ancient Mongolian pastoral culture known as the Deer Stone-Khirigsuur Culture roamed the steppes of Mongolia and eastern Eurasia between 1300 to 700 BC.
This culture is named after the beautiful carved standing stones ('deer stones') and burial mounds (khirigsuurs) it built across the Mongolian Steppe.
This nomadic tribe of peaceful horsemen is linked with some of the oldest evidence for nomadic herding and domestic livestock use in eastern Eurasia.
At both deer stones and khirigsuurs, stone mounds containing ritual burials of domestic horses – sometimes numbering the hundreds or thousands – are found buried around the edge of each monument.
Previous research has discovered these early herders were the first in eastern Eurasia to rely heavily on horses as livestock for food products.
They could also have been among the first to use horses for mounted riding.
The incorporation of bronze and metal mouthpieces for riding spread into eastern Eurasia during the early first millennium BC.
It gave riders more nuanced control over horses and enabled them to be used for new purposes - especially warfare.
Herders began to use metal bits they also developed a method for extracting the problematic 'wolf tooth'.
This would have been with a primitive blunt instrument to minimise pain - similar to the way most veterinary dentists would remove it today.
In doing so these early riders could control their horses in high-stress situations using a metal bit without accompanying behavioural or health complications.

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Dr Taylor says the development of riding and a horse-based pastoral economy was a key driver for the invention of equine veterinary care.
The incorporation of bronze and metal mouthpieces for riding spread into eastern Eurasia during the early first millennium BC.
It gave riders more nuanced control over horses and enabled them to be used for new purposes - especially warfare.
But using metal to control horses also introduced new oral problems - such as painful interactions with a vestigial tooth that develops in some animals, known as a 'wolf tooth.'

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Equine skeletons found in Mongolia have revealed that ancient dentistry was being practised more than a millennium earlier than thought. Pictured is a Mongolian herder removing first premolar, or 'wolf tooth', from a young horse during the spring round up using a screwdriver


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Pictured is the skull of a ritually-sacrificed horse, buried along with hooves, and the bones of the neck (not visible here). Dr Taylor and his colleagues found as herders began to use metal bits they also developed a method for extracting the problematic 'wolf tooth'

Dr Taylor and his colleagues found as herders began to use metal bits they also developed a method for extracting the problematic 'wolf tooth'.
This would have been with a primitive blunt instrument to minimise pain - similar to the way most veterinary dentists remove it today.
In doing so, these early riders could control their horses in high-stress situations using a metal bit without accompanying behavioural or health complications.
'From the American West to the steppes of Eurasia, the domestic horse transformed human societies, providing rapid transport, communication, and military power, and serving as an important subsistence animal', said Dr Taylor.

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The incorporation of bronze and metal mouthpieces for riding spread into eastern Eurasia during the early first millennium BC. Pictured is a horse skulls atop an ovoo, or ritual stone cairn, outside the city of Murun in Mongolia


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Pictured is a horse tooth showing modification by humans. The upper incisor, or 'wolf tooth' was recovered from a ritual horse burial belonging to the late Bronze Age Deer Stone-Khirigsuur Complex, at the site of Uguumur, Zavkhan, central Mongolia

He said Syrian texts from the Hittite Empire, dating to the 14th century BC, describe the proper feeding of chariot horses and treatment of key ailments.
In China, domestic horses first appeared during the end of the Shang Dynasty, around 1,200 BC.
Following their introduction to the region, horses became the basis for long-distance communication and transport, as well as military power, within only a few hundred years.

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In China, domestic horses first appeared during the end of the Shang Dynasty, around 1,200 BC. Pictured is a partial horse skeleton, buried within a small stone mound at a deer stone site in Bayankhongor, central Mongolia



Pictured is a map of Mongolia and archaeological sites mentioned in the text, along with time period and number of samples

'These results push back the earliest dates for equine dentistry by more than a millennium and suggest that nomadic peoples developed key innovations in veterinary care that enabled more sophisticated horse control, ultimately changing the structure of communication, exchange, and military power in ancient Eurasia', Dr Taylor said.
'In many ways, the movements of horses and horse-mounted peoples during the first millennium BC reshaped the cultural and biological landscapes of Eurasia', said Dr Nicole Boivin, director of the Department of Archaeology at the Max Planck Institute.
'Dr Taylor's study shows veterinary dentistry - developed by Inner Asian herders - may have been a key factor that helped to stimulate the spread of people, ideas, and organisms between East and West.'
http://blog.sina.com.cn/aganmu;安德(嗨,前一个无辜被封):
http://blog.sina.com.cn/kilarler
易涨易退山溪水,易反易覆小人心!君子不党,而小人喜欢拉帮结伙旁聚布公(《水浒传》就是例子)。相对文明的,有制度有文章,相对野蛮的,逐利贪冒,豺狼无厌。质胜文则野,文胜质则史,文质彬彬,然后君子。所有文化都要求忠诚,这也会影响到基因和思维方面。忠诚会限制人的独立自主,但往往会让人更有独立之精神更有自由之思想(然而假如整个社会制度有缺陷,又往往会导致“独立之精神也病,自由之思想也痛”)。这是内力的要求,这就是自然——内质(nature),就是道。根据矛盾论,内因起决定作用哟!所以修道者格物致知,也是为了反求诸己,修炼内心,文胜于质,文质彬彬。人性各异,人心不同,所以文化会催生各种不同的变异,百花齐放百家争鸣!同理,驯化过程也都是为了从“野蛮”走向“文明”,驯化过程也会催生不同的变异,所以作物、观赏植物、宠物、家畜品种繁多,性状各异。不过人道繁华,地道不均,天道公平,人法地,地法天,天法道,道法自然。无量天尊摩诃般若波罗蜜多,如同量子世界之于宏观宇宙,这又不是一个量级的道了。质胜文则野,大自然还是很任性的,所以自然物种多是粗野难驯,互相攻伐,其实也更容易包容异己,也正因此,野生动植物性状比较单一。


Why dogs can't kiss and make up: Researchers find they have lost the 'pack mentality' of wolves and simply avoid others after a disagreement

  • Team studied how dogs and wolves reconcile following a disagreement
  • Wolves were violent towards each other, but made up quickly
  • Dogs less likely to fight, but simply avoided each other rather than reconcile
By Mark Prigg For Dailymail.com

Published: 00:23 BST, 4 July 2018 | Updated: 00:27 BST, 4 July 2018




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Dogs find it far harder than wolves to forgive their friends, it has been revealed.
Researchers believe domestication has meant dogs have lost their 'pack mentality'.
The team from the University of Veterinary Medicine in Vienna studied how dogs and wolves reconcile with others of the same species following a disagreement.
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The researchers looked at the pattern of reconciliation in four captive wolf packs and compared them to rescue dogs at a shelter. The wolves were violent towards each ther, and fell out almost once an hour. However, they made up within ten minutes almost half the time.

This is a key skill for wolfpacks, they said.
'Highly cooperative social species are expected to engage in frequent reconciliation following conflicts in order to maintain pack cohesiveness and preserve future cooperation, they wrote in the Royal Society Open Science journal.
The researchers looked at the pattern of reconciliation in four captive wolf packs and compared them to rescue dogs at a shelter.
The wolves were violent towards each other, and fell out almost once an hour.
However, they made up within ten minutes almost half the time.








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The team from the University of Veterinary Medicine in Vienna studied how dogs and wolves reconcile with others of the same species following a disagreement, and found dogs find it far harder than wolves to forgive their friends

In the dogs, they came into conflict less often, but when they did, the results were violent and less likely to be resolved.
Fewer than one in five fights result in a swift reconciliation, they found.
'We provide evidence for reconciliation in captive wolves, which are highly dependent on cooperation between pack members, while domestic dogs, which rely on conspecific cooperation less than wolves, avoided interacting with their partners after conflicts.'
'Our results are in line with previous findings on various wolf packs living under different social and ecological conditions, suggesting that reconciliation is an important strategy for maintaining functional relationships and pack cohesiveness,' the researchers concluded.
They say the occurrence of reconciliation in dogs 'may be influenced by social and environmental conditions more than in wolves' and called for further research into how dogs deal with conflict.
http://blog.sina.com.cn/aganmu;安德(嗨,前一个无辜被封):
http://blog.sina.com.cn/kilarler
本帖最后由 癯鹤 于 2018-7-6 09:12 编辑
美洲引入狗狗的年代也超过了一万年!


Discovery of earliest known domestic dogs suggests Americans had canine companions more than 10,000 years ago

  • Researchers re-examined two dog skeletons found at the Koster site in Illinois
  • They also examined a third skeleton found in 1960 at the nearby Stilwell site
  • Analysis suggests domesticated dogs were in America over 10,000 years ago ...
    癯鹤 发表于 2018-6-19 11:37
然而(ranhaer,兰哈儿?),终究还是个凄美的传说。物是人非事事休,狗在种换基因变!这些美洲狗狗已经成了遥远的故事了!呜呼,它们成了美洲的尼安德特狗、丹尼索瓦狗!除了遗骸,据说只留下神秘疾病,证明它们不但曾经存在过,而且还深刻影响了当今狗族!
我就说嘛,卖家卖地纳身奴,转种转基因地安!对于畜禽和作物,改良、改换品种,常常会做得很绝,一点余地都没有(比如第18楼那牛头犬头牛)!所以我怀疑呢,中国远古还是有一些驯化物种,后来被外来物种——外来的畜禽给取代了。比如圣水牛什么的,不能因为没有今日基因后代,就是古人没有可能驯化它们。基因检测很关键,而且时常也能发现一些遗踪线索,比如上面第21楼关于中国家牛的遗传研究,就有一些奇妙的发现!


Native American dog breeds were almost completely wiped out by the arrival of Europeans, new research shows


  • Canines had lived alongside American tribes for more than 9,000 years
  • Arrival of Europeans in the beginning of the 15th century wiped them out
  • Disease, cultural persecution and biological changes are likely to blame
  • Strangely one close relative of these native dogs has survived
  • This is in the form of a canine cancer that has the same genome to original dog
By Phoebe Weston For Mailonline
Published: 19:00 BST, 5 July 2018 | Updated: 19:00 BST, 5 July 2018

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Native American dog breeds were almost completely wiped out by the arrival of Europeans, according to new research.
The canines had lived happily alongside indigenous American tribes for more than 9,000 years.
But the arrival of Europeans and their pets in the beginning of the 15th century all but wiped out ancient native or 'pre-contact' dogs.
Dogs that we think of as American - such as the Labrador and Chihuahuas - are in fact descended from dogs from the Old World, researchers found.
Their near-total disappearance was probably due to the combined effects of disease, cultural persecution and biological changes.
Strangely one close relative of these native dogs has survived in the form of a world-wide transmissible canine cancer that has an identical genome to the original dog.
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Native American dog breeds were almost completely wiped out by the arrival of Europeans, according to new research. Pictured is a dog burial from Illinois


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The canines had lived happily alongside indigenous American tribes for more than 9,000 years. But the arrival of Europeans and their pets in the beginning of the 15th century all but wiped out ancient native or 'pre-contact' dogs

The genetic study of pre-contact dogs found they possessed genetic signatures unlike dogs found anywhere else in the world.
They were not domesticated North American wolves as some had previously speculated, according to the research led by the University of Oxford, University of Cambridge, Queen Mary University of London, and Durham University.
Scientists say they followed their human masters over a land bridge that once connected North Asia and the Americas.
The study is the first comprehensive genomic analysis of ancient dogs in the Americas.

Researchers looked at nuclear DNA which is inherited from both parents, along with mitochondrial DNA, which is passed down only from mothers to their offspring.
They compared the genomic signatures from 71 mitochondrial and seven nuclear genomes of ancient North American and Siberian dogs.
The oldest dog remains in the Americas date to about 9,000 years ago, many thousands of years after people began migrating over a land bridge across the Bering Straits.
The results showed the ancient dogs dispersed to every part of the Americas, migrating with their human counterparts.

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The dogs' history parallels that of ancient humans who migrated from North Asia to North America. Dots (pictured) represent sites from which the bones of ancient dogs were collected for the new analysis along with the age of the bones


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Pictured is a ritual burial of two dogs at a site in Illinois near St. Louis (660 to 1350 years ago). Prior to this research, the fate of pre-contact dogs and their relationship to modern American dog populations was largely unknown

WHAT HAPPENED TO NATIVE AMERICAN DOGS?Native American dog breeds were almost completely wiped out by the arrival of Europeans, according to research led by the University of Oxford, University of Cambridge, Queen Mary University of London, and Durham University.
The oldest dog remains in the Americas date to about 9,000 years ago, many thousands of years after people began migrating over a land bridge across the Bering Straits.
The results showed the ancient dogs dispersed to every part of the Americas, migrating with their human counterparts.
But the arrival of Europeans and their pets in the beginning of the 15th century all but wiped out ancient native or 'pre-contact' dogs.
Dogs that we think of as American - such as the Labrador and Chihuahuas - are in fact descended from dogs from the Old World, researchers found.
Their near-total disappearance was probably due to the combined effects of disease, cultural persecution and biological changes.

[url=][/url][url=][/url][url=][/url][url=][/url]

'It is fascinating that a population of dogs that inhabited many parts of the Americas for thousands of years, and that was an integral part of so many Native American cultures, could have disappeared so rapidly', said lead author Dr Laurent Frantz, from Queen Mary University.
'Their near-total disappearance is likely due to the combined effects of disease, cultural persecution and biological changes starting with the arrival of Europeans', she said.
Senior author Professor Greger Larson, Director of the Palaeo-BARN at Oxford said that the study demonstrateed the history of humans is mirrored in our domestic animals.
'People in Europe and the Americas were genetically distinct, and so were their dogs', he said.
'And just as indigenous people in the Americas were displaced by European colonists, the same is true of their dogs.'
Prior to this research, the fate of pre-contact dogs and their relationship to modern American dog populations was largely unknown.

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Scientists say they followed their human masters over a land bridge that once connected North Asia and the Americas. Ancient dog burials like this one found at the Janey B. Goode site near Brooklyn, Illinois, provided genetic material for the study


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Pictured is a dog burial from Illinois, dated to around 10,000 years ago. The genome of these ancient dogs is still present in a congenital cancer seen in modern dogs, according to the study, published in Science

'Our study confirms that they likely originated in Siberia, crossing the Bering Strait during initial human migrations', said lead archaeologist and co-first author Dr Angela Perri, of Durham University.
'In fact, we now know that the modern American dogs beloved worldwide, such as Labradors and Chihuahuas, are largely descended from Eurasian breeds, introduced to the Americas between the 15th and 20th centuries', she said.
However, the genome of these ancient dogs is still present in a congenital cancer seen in modern dogs, according to the study, published in Science.
Canine transmissible venereal tumours (CTVT) are spread between dogs by the transfer of living cancer cells during mating.
CTVT originated from the cells of a single dog, known as the 'CTVT founder dog', that lived several thousand years ago.

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Their near-total disappearance was probably due to the combined effects of disease, cultural persecution and biological changes. Pictured is a dog burial from Illinois


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Anthropology Professor Ripan Malhi, of the University of Illinois, said the new findings reinforced the idea that early human and dog inhabitants of the Americas faced many of the same challenges after European contact

Remarkably, the research revealed that the dog that first spawned CTVT was closely related to American pre-contact dogs.
Overall the results indicate that this cancer, now found worldwide, possesses a genome that is the last remaining vestige of the dog population that was once found all across the Americas.
'It's quite incredible to think that possibly the only survivor of a lost dog lineage is a tumour that can spread between dogs as an infection,' said Maire Ní Leathlobhair, co-first author from the Department of Veterinary Medicine at the University of Cambridge.
'Although this cancer's DNA has mutated over the years, it is still essentially the DNA of that original founder dog from many thousands of years ago.'
Anthropology Professor Ripan Malhi, of the University of Illinois, said the new findings reinforced the idea that early human and dog inhabitants of the Americas faced many of the same challenges after European contact.
'It is known how Indigenous peoples of the Americas suffered from the genocidal practices of European colonists after contact', he said.
'What we found is that the dogs of Indigenous peoples experienced an even more devastating history and a near-total loss, possibly as a result of forced cultural changes and disease.'
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