Kkkhhhaaannn!!!

By Razib Khan | February 12, 2012 5:03 pm

My post, 1 in 200 men direct descendants of Genghis Khan, is linked up somewhere almost every week. Why is it so popular? No idea. But one thing that has come to mind: we’ve come a long way in since the early 2000s in assembling databases of human scientific genealogies. Soon enough a substantial proportion of the males in the human race will have their Y chromosomes typed. What proportion of these individuals are going to be part of a “star-shaped phylogeny,” implying a radiation from a single individual relatively recently in the past? My own suspicion is a great deal. The Khan lineage is simply a relatively recent one as these things go. How did R1a1 come to be so widespread?

CATEGORIZED UNDER: Anthroplogy
MORE ABOUT: Genghis Khan
  • http://blogs.scientificamerican.com/thoughtful-animal Jason G. Goldman

    It’s obviously because I asked you to write that post. You’re welcome! :-)

  • http://www.scribd.com/doc/74944514/ Robert Dole

    You (and Cochran) fascinate me.

  • Grey

    “Why is it so popular?”

    Desire for a famous ancestor maybe – kings wanting descent from Gods, plebs wanting descent from kings.

  • Mark Plus

    You can look at this another way: Male sexual behavior follows a Pareto distribution, where a few alpha males get most of the sexual opportunities, and with the most fertile women; while the lower status men have to fight for the scraps, leavings, rejects and leftovers. At the other, far end of the distribution, over countless generations a lot more men than we realize probably died as virgins.

  • Bobby LaVesh

    1 in 200 men are direct descendants of Chengis Khan.

    Meaning even more may carry his X chromosome- or any number of his other chromosomes?

    How do we know exactly that 1 in 200 men are descended from Chengis and not one of his brothers- if memory recalls he had 5 or 6 brothers- each should have had the same Y chromosome.

    Would it not also be possible that his Y chromosome was already in distribution in his tribe? Is there anyway to know that the 1 in 200 is really descended from him instead of his father, his grand father, his great-great-great-great grandfather.

    Have we access to his father’s Y chromosome to be able to compare it to his and notify a specific mutation?

    Members of his tribe would all have been fairly closely related- especially on the Y chromosome- women were often taken/exchanged/kidnapped from neighbouring tribes- but the men were all related. It would have been men from his tribe who would have been amongst the most powerfull- so if most of the men in his tribe shared a Y chromosome- they all would likely have been amongst Chengis’s men doing the raping, pillaging, taking the choice consorts from conquered lands and doing the DNA exchanges from the very beginning.

    Unless there is specific evidence that the genes on his Y chromosome belonged exclusively to him- I’d say it is more likely 1 in 200 men were direct descendants from Chengis’s tribe rather than from him specifically.

  • dcwarrior

    Further to #5, how widely distributed was that Y chromosome when Genghis had it, possibly even beyond Genghis’ family?

    Also, what is the probability that 1 in 200 persons are descended from a gene belonging to any particular person that long ago, given that each gene was probably widely spread in the population at the time?

    This is a fascinating question.

  • Euler

    There seem to be some big problems with this scenario. Unless there is specific selection for the Y chromosome over the rest of the genome, then if 8% of a population has Genghis Khan’s genome, wouldn’t you expect on average that people in that population get 8% of their entire genome from Genghis Khan? I’m not an expert, so I could be wrong, but it seems like that’s right since if the entire genome is selected at the same level, then all the genes on average statistically should be represented at the same fraction. Yet, you mention Timur, who had a descendant who married the daughter of Chagatai Khan, giving him great prestige. That suggests there was no particular emphasis on the Y-chromosome.

    Also, you would expect that after x generations, if there are N direct male descendants, there should be about N*2^x descendants overall until cousin marriage becomes significant. By the time the Y chromosome frequency changes from 1 individual to 1% of the population, the total number of descendants should be much much higher than 1%. 2^7 is already 128. Unless the descendants of Genghis Khan marry very endogenously, you quickly reach the point where most people are descendants of Genghis Khan. It is hard to imagine social selection carrying the frequency from 1% to 8% when most people are already descendants of Genghis Khan.

    Again, I’m not an expert, I just find this interesting. So, maybe you can tell me how I’m thinking wrongly.

  • 020.92

    Geek culture

    re: H2G2, Mr. Prosser and all that.

  • Rob

    To pick up on Mark Plus, I wonder how much of the interest in the post lies in how it seems to provide something of a back-story for certain apparent sex differences in contemporary life — namely, those of the sort explored by Baumeister in his 2007 APA address and, more expansively, in his book. That, at least, is how I took interest in the topic and discovered your post on it.

  • Onur

    The “Genghis Khan Y-chromosomal” research is unfortunately outdated (both in terms of dating methods and the knowledge of haplotypes and sub-haplogroups). We need a reanalysis of the relevant Y-chromosomes with the current genetic knowledge and techniques to either confirm or refute the conclusions of the previous research. According to some dating methods, rather than being connected to Genghis or his family or tribe, the relevant Y-chromosomal lineage spread ~1000 years before the time of Genghis and is perhaps connected to the Xiongnu, Hunnic and/or Turkic expansions.

  • http://blogs.discovermagazine.com/gnxp Razib Khan

    Again, I’m not an expert, I just find this interesting. So, maybe you can tell me how I’m thinking wrongly.

    lots of your objections are taken care of by thought experiments. for example, all Y chromosomes coalesce back to ~100 thousand years ago. are we descended in totality from this one man? no.you can’t substitute uniparental lineages for total genome content and vice versa.

    it was probably his tribe. but i assume that the ‘golden family’ makes the lion’s share of the contribution. even his favored brothers, like khasr, were marginalized in relation to his own sons.

  • gcochran

    Of course it was Genghis. I shouldn’t have to explain this. The first key fact is that you pick up a heap of resources when you rule an entire country – and non-rulers don’t. The second is that kingship was passed down in the male line. Genghis ruled a big chunk of territory, and he had a harem. His sons (by Bortai) ruled whole countries, and they had harems, as did _their_ sons for a number of generations. His brothers didn’t inherit kingdoms: his cousins didn’t, nor did their descendants. Moreover, even after the Genghisid dynasties fell in places like China, direct male descendants of Genghis Khan were considered the only natural leaders in nomad society for many centuries: you’d put a member of the Golden Family in charge even if you were organizing a weenie roast. Moreover, people _knew_ who were members of the Golden Family – the Hazara do, to this day – and the genetic investigations largely confirm the oral histories.

    The total number of descendants of Genghis Khan – counting maternal lineages, not just those who are the sons of the sons of the sons etc – must be in the hundreds of millions, or more. If you looked for lots of oddly common chromosomal segments, considered overlap, etc, you could probably come fairly close to reconstructing Genghis’s genome. That’s just what we need.

    This is one of the many cases where trying to sound more reasonable just makes you more wrong.

  • Euler

    lots of your objections are taken care of by thought experiments. for example, all Y chromosomes coalesce back to ~100 thousand years ago. are we descended in totality from this one man? no.you can’t substitute uniparental lineages for total genome content and vice versa.

    Thanks, that is a weakness in what I said, although I still have reservations because the difference in the fractions of the uniparental lineages and the rest of the genome should be due to genetic drift and natural selection. It seems very quick for genetic drift and if the direct male line is not favored, there is no selection above the selection for the rest of the genome.

    His sons (by Bortai) ruled whole countries, and they had harems, as did _their_ sons for a number of generations.
    But if the kings have harems, that only gives an arithmetic level of growth. To go exponential, all of the illegitimate sons would need harems, and then all of those sons they have would need harems, until 8% of the population has harems.

    For this to work, you need their to be a high level of prestige attached to being a descendant of Genghis Khan by a woman in his harem. But think about this: How come no one can be sampled who is a known descendant of Genghis Khan? People must have stopped keeping track a long time ago, and it must be extremely easy to fake it. Remember, when 1% of the population are direct male descendants of Genghis Khan, you still have another 700% increase to account for. How could prestige be so widely distributed along specifically a male line on the scale of a continent?

  • http://blogs.discovermagazine.com/gnxp Razib Khan

    How come no one can be sampled who is a known descendant of Genghis Khan? People must have stopped keeping track a long time ago,

    this is totally false. in case, greg above explicitly lays out why it is false (the hazara). but the khalka mongol nobility all claim descent, and are jealous of it.

    It seems very quick for genetic drift and if the direct male line is not favored, there is no selection above the selection for the rest of the genome.

    fyi, i have a hard time understanding your argument. so if i don’t respond, probably due to confusion as to what you are saying.

  • Bobby LaVesh

    #12- Chengis wouldn’t have been the only one with a harem. Many important men would have.

    Also, his whole tribe would have been raping- producing potentially thousands of Chengis “Y-chromosome” babies (depending on if they shared his Y-Chromosome) in just one generation.

    Depending on how far the Y-Chromosome went back- the neighbouring tribes were somewhat related- splitting off from each other as they got too big (or political infighting emerged). Neighbouring tribes who were the ones he got to join on his rampages early on could also have had his Y chromosome.

    I’m not doubting that millions of people today may show direct descent from Chengis down the “Y” line (many millions more from other chromosomes)- I’ve no doubt that Chengis makes up more than his share of those “Y” descendants.

    Did tribal leaders from his vassel tribes have his Y to spread in their harems? ALL the soldiers would have been raping. As many villages, towns, cities that they overthrew- those tribes that had been with him from the early days (those closest related to him) could have sired many children each.

    It really depends on how wide-spread his Y chromosome was. Did everyone in his tribe have it- did the neighbouring tribes have it? Was it common amongst ALL the tribes?

    I don’t think we will ever know if that 1 in 200 is from him alone, his family alone, his tribe alone- or if the whole horde helped out in significant numbers to spread their happy little Y chromosomes.

    If Chengis’s “Y” was not the only one being spread- if other important men with harems and the propensity to rape their way across a continent had different Y’s – how many men out of 200 can trace their Y chromosome back to the mongol invasion from a different patriarch? Even if not as responsible as Chengis himself- other important men from that same invasion must likewise have thousands of male descendants today- if for no other reason than population growth and a high 1st generation output.

  • Euler

    this is totally false. in case, greg above explicitly lays out why it is false (the hazara). but the khalka mongol nobility all claim descent, and are jealous of it.
    I meant, how come we don’t know of a specific person who definitely has Genghis Khan’s Y-chromosome. For instance, the majority of the Hazara do not have the Y-chromosome in question according to the graph on your previous post. If the lineage was tracked carefully to give prestige to individuals who are direct descendants, then surely, we would know at least one person in the world who could demonstrate to a reasonable degree of certainty that they are a direct male descendant of Genghis Khan, but apparently, we can’t.

    If the prestige attached to that lineage was very great, but the record keeping was poor, it would be in a lot of people’s interest to fake it. At the point where 1% of people are direct male descendants, there would conservatively be millions to 10’s of millions of total descendants considering this is much higher than the direct descendants. In order to account for the further 700% increase in the share after that, there would need to be very good record keeping to assign prestige accurately enough, even at this stage where it becomes highly impractical.

  • http://blogs.discovermagazine.com/gnxp Razib Khan

    not to be a dick, but wikipedia is your friend people. in any case, the borgijin mongol clan were relatively marginal until a few generations before temujin. in fact, it is possble they were a forest tribe in living memory of his grandparents.

  • megan130

    What about the other DNA study that in Ireland that said upto 80-90 percent? indigenous to the island were descended from one Irish Chieftain who was the first one to lead all of the clans from before the Viking invasion? Has the British research that despite later Viking and Anglo-Saxon & Norman invasions, the majority of the people are Celtic, ever been written about here?

  • http://blogs.discovermagazine.com/gnxp Razib Khan
  • Naughtius Maximus

    @18
    The current thinking is that the snp arose in North England/Scotland as that is where there is mist variance. The initial announcement of a link to Niall of the Nine hostages seemed to be an attempt to put a famous face to it. Niall or a figure like him was most likely responsible for the spread of it. People spreading La Tene culture, abScottish group known as the cruithin and mercenaries have all been suggested as bringing it to Ireland.

  • Grey

    “You can look at this another way: Male sexual behavior follows a Pareto distribution, where a few alpha males get most of the sexual opportunities, and with the most fertile women; while the lower status men have to fight for the scraps, leavings, rejects and leftovers.”

    And where did this ever happen? Only in the world of the kind of “alphas” who have no knowledge or understanding of violence could anyone believe this nonsense. It can never just be a few or they’d be killed. They need a gang to protect them and the gang needs to be kept happy and outside the modern welfare environment the gang need to be fed and watered so that needs a class of people who provide that and enough of them need to be kept happy too.

    “Chengis wouldn’t have been the only one with a harem. Many important men would have.”

    I find it hard to believe any amount of harems amidst a normal population distribution could create the 1 in 200 effect (much higher near the epicentre i assume?) It seems much more likely to me the scale of mongol massacres was as recorded in the histories allowing the proportion of genghis Y chromosome to multiply as the population grew back to fill the void.

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This blog is about evolution, genetics, genomics and their interstices. Please beware that comments are aggressively moderated. Uncivil or churlish comments will likely get you banned immediately, so make any contribution count!

About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at http://www.razib.com

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