观网网友 刘三解freestyle 写了一篇很有意思的文章《解答：匈奴西迁灭亡古罗马帝国，靠谱吗？》https://user.guancha.cn/main/content?id=52687。这篇文章对我们通常的知识——汉朝把匈奴往西推，匈奴向西跑到欧洲然后灭了罗马帝国——进行了质疑，认为这是不可能的。
笔者对历史问题都很感兴趣，但不是专业人士，不敢发表置评。但是对文章中的一个论据——匈人并不乐于食用乳制品，由此推论匈人并不是匈奴人——提出一点科学方面新的研究成果，供网友 刘三解freestyle 参考。
上周的《科学》杂志有一篇很有意思的新闻——《早期的蒙古人食用乳制品，但缺乏消化它的基因 Early Mongolians ate dairy, but lacked the gene to digest it Early Mongolians ate dairy, but lacked the gene to digest it》http://science./content/362/6415/626。这篇新闻介绍了德国耶拿马克斯普朗克人类历史科学研究所的Christina Warinner的团队研究了早期蒙古高原的人类化石，发现蒙古高原的游牧民族跟世界其他地方的游牧民族不一样，他们有95%的人有乳糖不耐症 lactose intolerance。由于现代蒙古人通过使用细菌消化乳糖来消化乳制品，因此，这个团队推断古代蒙古人也是借助微生物来消化牛奶。
这一个研究成果给“匈人并不乐于食用乳制品”这一现象提出来了一种猜想：匈人就是从蒙古高原跑到欧洲去的匈奴人。有极大可能是因为欧洲没有蒙古高原的微生物，匈人（匈奴人）没法子消化乳制品，所以才出现了“匈人并不乐于食用乳制品”的现象。
总之，“匈人并不乐于食用乳制品”这个现象是不能拿来证明匈人不是匈奴人这一论断。
翻页是新闻全文和谷歌翻译
早期的蒙古人食用乳制品，但缺乏消化它的基因
3000多年前，成群的马，羊，牛，牦牛点缀着蒙古大草原。他们的人类看护人员吃了牲畜，并用自己的动物骨头埋葬了他们。现在，对古代牙齿上的沉积物的分析表明，早期的蒙古人也会给它们的动物挤奶。这似乎并不令人惊讶。但同样古代个体的DNA表明，作为成年人，他们缺乏消化乳糖的能力，乳糖是牛奶中的关键糖。
研究结果加深了一个新兴的难题，挑战了人们如何演变乳糖酶持久性，以及成年后产生乳汁消化酶的能力。在其他研究中，“我们现在知道乳业是在我们看到乳糖酶持续存在的4000年前进行的，”德国耶拿马克斯普朗克人类历史科学研究所的Christina Warinner说。凭借悠久的历史和乳业文化，“蒙古向我们展示了如何”。
正如哥本哈根大学的葡萄糖蛋白组学家马修·柯林斯（Matthew Collins）所说的那样，“我们认为我们理解了一切，但随后我们得到了更多的数据，看看我们有多天真。”
世界上大多数人在童年后都失去了消化乳糖的能力。但在牧民人群中，故事发生了，文化与DNA并存。允许人们在成年后消化牛奶的突变会给他们的携带者带来优势，使他们能够获得丰富的全年脂肪和蛋白质来源。奶制品随着改编而传播，解释了为什么它在欧洲，非洲和中东的牧民群体中很常见。
但仔细研究世界各地的文化习俗已经对这种情况提出了挑战。例如，在现代蒙古，传统牧民从乳制品中获得超过三分之一的卡路里。他们给七种哺乳动物喂奶，产出各种奶酪，酸奶和其他发酵乳制品，包括用母乳制成的酒精。 “如果你可以挤奶，他们会在蒙古做” Warinner 说。然而，95％的人患有乳糖不耐症。
Warinner想知道最近在蒙古是否出现了乳业，或者早期的蒙古人是否有乳糖酶持续存在，然后在人口更替中失去了乳制品。那里的古代人可能从着名的Yamnaya牧民那里获得了这样的突变 - 其中约三分之一是乳糖酶持续性 - 他们在5000年前从欧亚大陆中部向东西方横扫。
为了找到答案，她的团队分析了位于公元1300年之间的蒙古文化Deer Stone-Khirigsuur Complex的六个遗址中的人类遗骸。和公元900年建有用立石标记的墓冢。因为这些游牧民很少建造永久性建筑物，并且持续的风将土壤与盆地碎片和垃圾坑一起剥离，因此饮食的考古证据很少。因此，Warinner的Max Planck同事谢万威尔金（Shevan Wilkin）从九个骨骼中检测牙齿结石 - 牙齿上的硬斑块 - 并测试它是否为关键蛋白质。
结石产生来自绵羊，山羊和牛的蛋白质，如牦牛或牛。然而来自牙齿和腿骨的DNA显示牧民不耐乳糖。研究小组本周在“美国国家科学院院刊”上报道说，他们只携带了一些来自Yamnaya的DNA。柯林斯说：“他们正在利用这些动物进行乳业，即使它们不是乳糖酶持久性的。”
乳制品和DNA之间的脱节不仅限于蒙古。研究人员最近在土耳其Çatalhöyük的罐子上发现了牛奶蛋白质，这些蛋白质在9000年前可以追溯到驯化开始，在乳糖酶持续存在之前已有4千年。柯林斯说：“整个地方似乎都出现了牛奶蛋白质，我们期望看到的奇妙演变不会发生。”
现代蒙古人通过使用细菌消化乳糖来消化乳制品，将牛奶变成酸奶和奶酪，以及西方饮食中未知的丰富乳制品。古代牧民可能采取了类似的策略。 “控制和操纵微生物是整个转型的核心......这使他们能够拥有一种乳业文化，”Warinner说。
遗传学家正在回到绘图板，以了解为什么乳糖酶持久性是常见的 - 并且显然是在一些乳制品种群中选择但在其他人中没有。 “如果已经有文化解决方案，为什么会有自然选择的信号呢？”德国美因茨约翰内斯古腾堡大学的遗传学家约阿希姆汉堡问道。
乳业如何到达蒙古也是一个难题。 Yamnaya广泛的遗传签名显示他们取代了许多欧洲和亚洲青铜时代的人口。但他们似乎已经停在蒙古西部的阿尔泰山脉。 “文化上，这是一个非常充满活力的时期，但人们自己似乎并没有改变，”华纳说。她认为即使Yamnaya没有将他们的基因贡献给东亚，他们确实传播了他们的文化，包括乳业。 “这是一个采用草原生活方式的当地人口。”
鉴于这些令人惊讶的结果，Warinner有一个新的目标：找出哪些微生物帮助蒙古人消化牛奶。
http://science./content/362/6415/626
Early Mongolians ate dairy, but lacked the gene to digest it
More than 3000 years ago, herds of horses, sheep, and cows
or yaks dotted the steppes of Mongolia. Their human caretakers ate the
livestock and honored them by burying the animal bones with their own.
Now, analysis of deposits on ancient teeth shows that early Mongolians
milked their animals as well. That may not seem surprising. But the DNA
of the same ancient individuals shows that as adults they lacked the
ability to digest lactose, a key sugar in milk.
The
findings deepen an emerging puzzle, challenging an oft-told tale of how
people evolve lactase persistence, the ability to produce a
milk-digesting enzyme as adults. From other studies, “We know now
dairying was practiced 4000 years before we see lactase persistence,”
says Christina Warinner of the Max Planck Institute for the Science of
Human History in Jena, Germany. With its long history and culture of
dairying, “Mongolia shows us how.”
As University of
Copenhagen paleoproteomicist Matthew Collins, who was not on the team,
puts it, “We thought we understood everything, but then we got more data
and see how naïve we were.”
Most people in the world
lose the ability to digest lactose after childhood. But in pastoralist
populations, the story went, culture and DNA changed hand in hand.
Mutations that allowed people to digest milk as adults would have given
their carriers an advantage, enabling them to access a rich, year-round
source of fat and protein. Dairying spread along with the adaptation,
explaining why it is common in herding populations in Europe, Africa,
and the Middle East.
But a closer look at cultural
practices around the world has challenged that picture. In modern
Mongolia, for example, traditional herders get more than a third of
their calories from dairy products. They milk seven kinds of mammals,
yielding diverse cheeses, yogurts, and other fermented milk products,
including alcohol made from mare's milk. “If you can milk it, they do in
Mongolia,” Warinner says. And yet 95% of those people are lactose
intolerant.
Warinner wondered whether dairying arose
recently in Mongolia or whether early Mongolians had lactase persistence
and then lost it in a population turnover. Ancient people there might
have picked up such mutations from the famed Yamnaya herders—about a
third of whom were lactase persistent—who swept east and west from
central Eurasia 5000 years ago.
To find answers, her
team analyzed human remains from six sites of the Deer Stone-Khirigsuur
Complex, a Mongolian culture that between 1300 B.C.E. and 900 B.C.E.
built burial mounds marked with standing stones. Because those nomads
rarely built permanent structures, and constant winds strip away the
soil along with pot fragments and trash pits, archaeological evidence
for diet is scarce. So Warinner's Max Planck colleague Shevan Wilkin
took dental calculus—the hard plaque that builds up on teeth—from nine
skeletons and tested it for key proteins.
The calculus
yielded milk proteins from sheep, goats, and bovines such as yak or cow.
Yet DNA from teeth and leg bones showed the herders were lactose
intolerant. And they carried only a trace of DNA from the Yamnaya, the
team reports this week in the Proceedings of the National Academy of Sciences. “They're exploiting these animals for dairying even though they're not lactase persistent,” Collins says.
That
disconnect between dairy and DNA isn't limited to Mongolia. Researchers
recently found milk proteins on pots at Çatalhöyük in Turkey, which at
9000 years old dates to the beginnings of domestication, 4 millennia
before lactase persistence appears. “There seem to be milk proteins
popping up all over the place, and the wonderful evolution we expected
to see isn't happening,” Collins says.
Modern Mongolians
digest dairy by using bacteria to digest lactose for them, turning milk
into yogurt and cheese, along with a rich suite of dairy products
unknown in the Western diet. Ancient pastoralists may have adopted
similar strategies. “Control and manipulation of microbes is core to
this whole transformation … that enables them to have a dairying
culture,” Warinner says.
Geneticists are going back to
the drawing board to understand why lactase persistence is common—and
apparently selected for—in some dairying populations but absent in
others. “Why is there a signal of natural selection if there was already
a cultural solution?” asks Joachim Burger, a geneticist at Johannes
Gutenberg University in Mainz, Germany.
How dairying
reached Mongolia is also a puzzle. The Yamnaya's widespread genetic
signature shows they replaced many European and Asian Bronze Age
populations. But they seem to have stopped at the Altai Mountains west
of Mongolia. “Culturally, it's a really dynamic period, but the people
themselves don't seem to be changing,” Warinner says. She thinks even
though the Yamnaya didn't contribute their genes to East Asia, they did
spread their culture, including dairying. “It's a local population that
has adopted the steppe way of life.”
Given these surprising results, Warinner has a new goal: To figure out just which microbes helped Mongolians digest milk.
