狗是如何演化成人類最忠心伙伴的

海德沙龍?07-29 16:44?

閱讀數(shù)：29196

我們將狗當(dāng)作實(shí)用工具繁育，但最后它們成了我們最忠實(shí)的盟友。

Man and dog share a long history. In much of the world, a history as old as humanity. The latest genetic evidence now tells us that the emergence of the domestic dog lineageoccurred soonafter the human expansion out of Africa 50,000 years ago, in the depths of the last Ice Age. We came. We saw. And we befriended. This we knew, but now we can closely examine how.A paper out today in?Scienceuses 27 ancient dog genomes from the past 11,000 years to construct an evolutionary history nearly as rich as that produced by human population geneticists over the last decade.

人類和狗有著悠久的共同史。在世界上許多地方，這段歷史和人類自身一樣久遠(yuǎn)。最近的遺傳證據(jù)告訴我們，在五萬年前上一次冰期正盛時(shí)，人類從非洲出走向外擴(kuò)張，家犬譜系不久也跟著出現(xiàn)了。我們到來，我們相見，我們成為朋友，這是我們已知的，但如今我們能夠詳細(xì)考察這一過程。今天（指 2020 年 10 月 30 日）發(fā)表于《科學(xué)》的一篇論文中，研究小組利用過去 11000 年 27 個(gè)古代狗的基因組構(gòu)建出了一段狗的演化史，它幾乎和人類群體遺傳學(xué)家過去十年為人類構(gòu)建的演化史一樣豐富。

The authors found five lineages of ancient dogs that were present at the end of the last Ice Age. These were the dogs that interacted with human migrations during the rise of agriculture and the fall of civilizations to produce the riotous dog diversity that we know today. Familiar breeds like the Pekingese and the St. Bernard, as well as stray Asian village mutts, they’re all the products of a deep shared history, which has left its imprint on the genetic variation of modern dogs.

作者發(fā)現(xiàn)，上一次冰期結(jié)束的時(shí)候存在五個(gè)古代狗譜系。農(nóng)業(yè)興起，文明衰落，在此期間狗與人類遷徙的互動(dòng)，產(chǎn)生了我們?nèi)缃袼募姺钡墓贩N多樣性。這段深遠(yuǎn)共同史在現(xiàn)代狗的遺傳變異中刻下了印記，獅子狗、圣伯納犬，以及亞洲流浪土狗等常見品種都是這段歷史的產(chǎn)物。

The dog-human relationship has always been special in several ways. Our canine companions are well adapted to us, in that they canengage with humans socially?in a manner no other animal seems equipped to, not even our closest relatives, the chimpanzees. This is thanks to tens of thousands of years of co-evolution. In a very real sense the evolutionary niche of the domestic dog is the human mind. Wolves may havehigher IQs, and yet there are 1,500–3,000 times more dogsalive today. Perhaps it was smarter to be friendly than just smart.

在許多方面，人和狗的關(guān)系一直都是特別的。我們的犬類伙伴很好地適應(yīng)了我們，它們能夠與人類親密交往，似乎沒有其他動(dòng)物能做到這個(gè)程度，甚至我們的近親黑猩猩也做不到。這要?dú)w功于數(shù)萬年的共同演化。甚至可以說，家犬的演化位就是人類心智。狼可能智商更高，但今天狗的數(shù)量是前者的 1500-3000 倍。也許光聰明還不行，你還得變得友善。

Dogs are the only domestic species who have been with us since the Pleistocene, which ended 11,500 years ago. Crops, cattle, and cats all came later, during the Holocene, after the Ice Age. When Siberians crossed over to the New World 15,000 years ago, they alsobrought their dogs. These dogs served many roles. Friend, beast of burden, and yes, even food.

狗是唯一自更新世（距今 11500 年前）就一直陪伴著我們的馴化物種。谷物、牛和貓都是在冰河時(shí)期之后的全新世才出現(xiàn)的。西伯利亞人 15000 年前向新世界邁進(jìn)時(shí)，他們也帶了自己的狗。這些狗有許多職責(zé)：朋友、役獸，沒錯(cuò)，甚至是充當(dāng)食物。

The New World dogs, who were present when the Spaniards landed in 1492, are one of the five great Pleistocene lineages from which all modern dogs descend. The authors of theSciencepaper call them the Neolithic Levant, Mesolithic Karelia, Mesolithic Baikal, ancient America, and the New Guinea singing dog. The last group includes Australian dingos and represents the ancient expansion of our species and its companions into Southeast Asia. Karelia is a region bordering Finland and Russia, while the Baikal dogs come from the lake of that name in east-central Siberia. These samples are termed Mesolithic because they are more recent than the Ice Age (7–11,000 years ago), but the peoples in Karelia and Baikal were still hunter-gatherers at that time. In contrast, the Neolithic Levant dogs date to 7,000 years ago, and were companions to agricultural populations.

新世界的狗在 1492 年西班牙人登陸新世界時(shí)就已存在，它們屬于五大更新世譜系之一，而所有現(xiàn)代狗的祖先都可追溯到這五大譜系。論文作者將這五大譜系命名為：新石器時(shí)代黎凡特犬、中石器時(shí)代卡累利亞犬、中石器時(shí)代貝加爾犬、古代美洲犬，以及新幾內(nèi)亞唱犬。最后一組中包括澳洲野犬，這表明我們這一物種及其犬類伙伴曾經(jīng)擴(kuò)張到了東南亞?？ɡ劾麃單挥诜姨m與俄羅斯接壤處，而貝加爾犬得名于西伯利亞中東部的同名湖。由于這些樣本要晚于冰河時(shí)期（距今 7 到 11000 年前），它們被歸進(jìn)了中石器時(shí)代，但當(dāng)時(shí)生活在卡累利亞和貝加爾的人仍然是狩獵-采集者。相反，新石器時(shí)代黎凡特犬可追溯至 7000 年前，而且它們陪伴的是農(nóng)業(yè)群體。

All modern dogs can be thought of as a mixture between these five early Holocene lineages. Despite their highly specific names, the Karelian and Baikal lineages represent huge geographic distributions, not just the sample sites. In this regard, they are analogous to modern humans. As David Reich has shown in his magisterial work,Who We Are and How We Got Here, the past 10,000 years have witnessed the merging of disparate hunter-gatherer tribes to form the peoples we see today, threaded together from distinct strands. This naturally leads us to the question: did human populations bring their particular dogs everywhere they went?

可以說，所有現(xiàn)代狗都是這五種全新世早期譜系之間的混合產(chǎn)物。盡管它們的名字都很具體，卡累利亞和貝加爾譜系所代表的不只是樣本地點(diǎn)，而是廣大地理分布。在這點(diǎn)上，它們類似于現(xiàn)代人類。如大衛(wèi)·賴克在其巨著《人類起源的故事》中所展示的，過去一萬年間不同狩獵-采集者部落的合并，形成了我們?nèi)缃袼姷?，不同支系交錯(cuò)融合而成的民族。這自然讓我們想到一個(gè)問題：人類群體有沒有把他們各自的狗帶到他們所至之處？

Comparing the relatedness of humans and relatedness of dogs, the authors of theSciencepaper found that there was a definite correlation. Phylogenetic trees of both dogs and humans exhibited strikingly similar shapes, indicating common underlying histories of separation and diversification. Analyses comparing the genetic data of dogs and humans revealed that they were tightly correlated. In fact, the relationship between the evolutionary trees for dogs and for humans is close enough that the tree for humans explains much of the pattern we see for dogs. There is an underlying structure which spans the two species, but also novel and curious deviations that alert us to particular stories.

論文作者比較了人類的親緣關(guān)系與狗的親緣關(guān)系，發(fā)現(xiàn)兩者有著明確相關(guān)性。狗和人類的系統(tǒng)發(fā)生樹形狀驚人相似，這表明他們或許潛存共同的分化和多樣化史。對人和狗的遺傳數(shù)據(jù)的對比分析顯示，他們之間緊密相關(guān)。實(shí)際上，狗和人類的演化樹之間的聯(lián)系是如此密切，人類的演化樹也可以解釋我們在狗身上看到的大部分模式。這兩個(gè)物種的底層結(jié)構(gòu)相互交叉，但也存在一些稀奇的差異，提醒我們要留意不尋常的情況。

Some of the stories are straightforward and to be expected. The dogs of ancient Europe are a mix of the Karelian and Neolithic Levant lineages. The latter clearly tagged along with the early farmers expanding out of the Near East. Further south in Europe, the dogs were more like those of the Neolithic Levant, while further north they were more like the Mesolithic Karelian dogs. American dogs were genetically closest to the Siberian dogs from Lake Baikal. Additionally, both these groups were closer to the dogs of Southeast Asia than they were to those of the Levant. This recapitulates the pattern for Eurasian peoples; East Asians are more closely related to Europeans than they are to Middle Eastern people.

有些情況是直觀和意料之內(nèi)的。古代歐洲地區(qū)的狗是卡累利亞譜系和新石器時(shí)代黎凡特譜系的混合產(chǎn)物，后者顯然是跟隨早期農(nóng)民從近東擴(kuò)張而來的。歐洲往南地區(qū)的狗更像新石器時(shí)代黎凡特犬，往北地區(qū)的狗則更像中石器時(shí)代卡累利亞犬。美洲地區(qū)的狗在基因上最接近貝加爾湖的西伯利亞犬。此外，這兩個(gè)種群與東南亞地區(qū)的狗的關(guān)系都比與黎凡特犬的關(guān)系更近。這重演了歐亞民族的模式；東亞人與歐洲人的關(guān)系比他們與中東人的關(guān)系更近。

But a few surprising findings confound our expectations. Four thousand years ago on the Volga steppe of Russia, on the cusp between Europe and Asia, the Srubna people flourished as part of a broad continuum of Indo-European peoples that stretched far to the west. While the Indo-European relatives of the Srubna came to dominate much of Europe, their dogs did not. The burials of early Indo-Europeans in Europe yield dogs whose heritage connected them to the Eurasian steppe and the Srubna, but this was a fleeting affair. The dogs of Northern Europe were not replaced by the dogs of the steppe, though the people largely were.

但一些出人意料的發(fā)現(xiàn)打亂了我們的預(yù)期。四千年前，在歐洲和亞洲交界的俄羅斯伏爾加大草原上，斯魯布納人作為一直延伸至西方的印歐連續(xù)體的一支興旺起來。雖然斯魯布納人的印歐近親后來主宰了歐洲大部分地區(qū)，他們的狗卻沒有。歐洲早期印歐人的墳地中發(fā)現(xiàn)了狗的遺骸，使得它們與歐亞草原和斯魯布納人產(chǎn)生了聯(lián)系，但這不過是短暫情緣。北歐地區(qū)的狗并沒有被草原上的狗取代，盡管人基本上是被取代了。

Instead, the heritage of the Srubna dog persists far to the east. Chinese dogs are mostly a mixture of ancient Southeast Asian dogs, related to the New Guinea singing dog and the dingo, plus the Srubna steppe dogs. While half the ancestry of modern Europeans comes from people related to the Srubna, very little of that ancestry is to be found in modern Chinese. And yet dogs are not the only evidence of the influence of steppe people in ancient China. In 1200 BC, chariots became prominent during the Bronze Age Shang dynasty, chariots whose design indicates borrowing from the Iranian peoples of Central Asia, direct descendants of the Srubna. It seems entirely likely that if chariots were brought to China during the Bronze Age, then so were dogs. While the dogs of the steppe found no welcome in Europe, the Chinese adopted them as their own.

然而，斯魯布納狗后代的身影卻不斷出現(xiàn)在更遙遠(yuǎn)的東方。中國地區(qū)的狗基本是古代東南亞地區(qū)的狗的混合產(chǎn)物，與新幾內(nèi)亞唱犬、野犬，以及斯魯布納草原狗有親緣。盡管現(xiàn)代歐洲人一半的血統(tǒng)來自與斯魯布納人有親緣的人，但在現(xiàn)代中國人中很少能發(fā)現(xiàn)這一血統(tǒng)。不過，狗并不是古中國受草原牧民影響的唯一證據(jù)。公元前 1200 年，在青銅時(shí)代的商朝，戰(zhàn)車變得重要起來，這些戰(zhàn)車的設(shè)計(jì)表明它們借鑒自中亞的伊朗人，即斯魯布納人的直系后裔。如果戰(zhàn)車在青銅時(shí)代被帶到了中國，那么狗也完全有可能。盡管草原狗在歐洲沒有受到歡迎，但中國人接納了它們，當(dāng)成了自己的狗。

It also sometimes happens that the migration of dogs runs counter to the migration of peoples. While humanity evolved in Africa and spread to the rest of the world through the Middle East, the origin of African domestic dogs reflects the reverse. Indigenous African breeds such as the Basenji descend from dogs of the Neolithic Levant. These dogs were likely brought south and west by the Near Eastern pastoralists who also brought cattle to the continent. Meanwhile, the ancient canine populations of the prehistoric Levant have been totally replaced by groups from Iran and Europe, so the primary legacy of the dogs that were associated with the first human cities is to be found today in Africa.

而且有時(shí)候，狗的遷徙和人的遷徙是背道而馳的。盡管人類在非洲進(jìn)化并經(jīng)中東擴(kuò)散到世界各地，非洲家犬的起源卻反映出相反情況。非洲本土犬種，如貝生吉犬，是新石器時(shí)代黎凡特犬的后裔。這些狗可能是近東牧民帶到南方和西方的，他們也把牛帶到了非洲大陸。同時(shí)，史前黎凡特的古代犬類種群完全被來自伊朗和歐洲的種群取代了。因此，與第一批人類城市相關(guān)的狗的主要遺跡今天可以在非洲找到。

But perhaps the biggest twist of the great canine diasporas is that their recent history is obscured and dominated by the phenomenon which has overshadowed our own species’ history: the rise, expansion, and domination of the world by Europe.

但也許犬類大散居的最大意外轉(zhuǎn)折是，它們近來的歷史和我們這一物種的歷史一樣，變得模糊不清，這主要是因?yàn)橐粋€(gè)現(xiàn)象：歐洲的崛起、擴(kuò)張，以及對世界的統(tǒng)治。

Modern European dogs do not descend from the full diversity of the continent. Rather, almost all European breeds today derive from a population best represented by a 5,000-year-old sample discovered in southern Sweden, an individual who was equally descended from Karelian and Levantine populations. The authors could not pinpoint the time or place that this replacement of the ancient lineages occurred, but by the time of the rise of European colonialism this single population had swept aside all the other ancient populations of the continent.

現(xiàn)代歐洲地區(qū)的狗并非沒有把大陸的多樣性都繼承下來。反而，今天幾乎所有歐洲犬種都衍生自一個(gè)種群，其最佳代表是瑞典南部發(fā)現(xiàn)的一個(gè) 5000 年前的樣本，這一個(gè)體同樣也是卡累利亞種群和黎凡特種群的后裔。作者無法確定這種古代譜系更替發(fā)生的時(shí)間或地點(diǎn)，但到歐洲殖民主義興起時(shí)，這一種群已經(jīng)將歐洲大陸的所有其他古代種群徹底取代。

Today the majority of the ancestry of dogs across the world is from this single European population that flourished 5,000 years ago. In the New World almost all the ancestry is now European, with the exception of the Arctic dogs. The venerable chihuahua has less than five percent of its ancestry from the dogs of the Aztecs. In Africa and the Middle East, most canine ancestry is now European, while European ancestry is often the majority in many Asian dog populations, and is substantial even in the dingo. Decolonization may have occurred politically, but the evolutionary history and genetic variation of dogs illustrate how powerful the hand of history can be and how long its shadow persists.

今天，世界上大多數(shù)的狗的血統(tǒng)都來自 5000 年前興旺的這一歐洲種群。除北極地區(qū)的狗以外，新世界幾乎所有狗的祖先如今都是歐洲種。歷史悠久的吉娃娃犬只有不到 5% 的血統(tǒng)來自阿茲特克的狗。在非洲和中東，大部分犬類的祖先如今都是歐洲種，歐洲血統(tǒng)在許多亞洲狗種群中往往占多數(shù)，甚至在野犬中也占相當(dāng)大比例。去殖民化或許已經(jīng)在政治層面上發(fā)生，但狗的演化史和遺傳變異展現(xiàn)了歷史之手的威力，以及其影響之久遠(yuǎn)。

Ancient DNA is like a genetic time capsule. We’ve spent these first decades honing our extraordinary new tools as we examine our own ancient human ancestry. But ours is hardly the only species with a history worth unpacking in such fascinatingly granular detail. Rather, we can look forward to the recent history of life on Earth being thoroughly illuminated via the evidence left behind by hardy fragments of DNA from creatures long gone.

古代 DNA 就像一顆遺傳時(shí)間膠囊。我們在研究自己的古人類祖先時(shí)把最初幾十年時(shí)間花在了磨練這一非凡的新工具上。不過，我們并不是唯一值得如此細(xì)致入微剖析其歷史的物種。反而，我們可以期待，透過這些早已消逝的生物的 DNA 片段留下的證據(jù)，地球生物的近代史將得到全面解釋。

The past 40,000 years has seen the transformation of our planet’s ecosystems due to humans. We live in the “Anthropocene” because our species has reshaped the planet to our ends. The evolutionary history of the domestic dog reflects humanity’s first, and longest, bioengineering experiment. We took a pack of wolves and transmuted it into a new species to walk alongside us. We bred dogs to be useful tools, but eventually they became our most loyal allies. We owe it to them to understand how they came to be as they are. And in the process we’ll inevitably continue to learn about ourselves.

由于人類，我們星球的生態(tài)系統(tǒng)在過去四萬年里發(fā)生了大幅轉(zhuǎn)變。我們這一物種為自己的目的重塑了這個(gè)星球，可以說，我們生活在「人類世」。家犬的演化史反映了人類第一次，也是最長的一次生物工程實(shí)驗(yàn)。我們把一群狼改造成了一個(gè)新物種，陪伴我們左右。我們將狗當(dāng)作實(shí)用工具繁育，但最后它們成了我們最忠實(shí)的盟友。我們有必要了解它們是如何變成今天這個(gè)樣子的。在此過程中，我們也必將不斷了解我們自己。

作者：Razib Khan

日期：2020 年 10 月 29 日

來源：Quillette