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Family trees: Tracing the world's ancestor
- est 14y ago> If you go back on average 1.77 times further again (35 generations) everyone in the population will have exactly the same set of common ancestors The problem is, different people have different life span. And different people can share the same parent. And sometimes in extreme cases, father - daughter love?
- reidrac 14y agoThere's a method to estimate that: http://en.wikipedia.org/wiki/Most_recent_common_ancestor#MRCA_of_all_living_humans http://en.wikipedia.org/wiki/Most_recent_common_ancestor#MRC... "Studies have used computer modelling to estimate that the MRCA of modern humans lived between 5,000 to 2,000 years ago."
- ktizo 14y agoGood to see a More or Less story on HN. For those who don't follow it, it is basically either a UK current affairs show for the mildly autistic, or a regular open university maths and economics lecture - http://www.bbc.co.uk/programmes/b006qshd http://www.bbc.co.uk/programmes/b006qshd
- mmahemoff 14y agoYeah something like Freakonomics (Tim Harford calls himself the undercover economist) and with equally admirable production qualities. I mentioned More or Less as my podcast recommendation on the very last HNpod actually.
- polshaw 14y agoglad to see this is still around.. enjoyed it a lot, i thought it was gone after the 3 month hiatus.
- polshaw 14y agoI really hate this trend for describing anything somewhat intellectual as 'autistic'.
- lutusp 14y agoYes, but psychologists love it -- it's bread on their table. Anyone sufficiently to the right of the mean I.Q. can be diagnosed on the autism spectrum, and be put into pointless therapy.
- alanctgardner 14y agoI don't really understand this view of therapy. In my experience, it's something you choose for yourself, because you recognize the need. The odds that you receive a psychiatric evaluation against your will and be compelled into therapy are amazingly slim. Especially for something like 'autism-spectrum' disorders, where the majority of sufferers appear to be high-functioning.
- lutusp 14y ago> I don't really understand this view of therapy. In my experience, it's something you choose for yourself, because you recognize the need. That would be nice, but it doesn't reflect reality. In schools, children are frequently given autism spectrum diagnoses against their better interests, or wishes, or the wishes of their parents (but not always -- sometimes parents force these things on their children). But the patient's wishes are often the lowest priority. Ideally, people would volunteer for therapy solely on issues they choose for themselves. But this isn't how clinical psychology works in modern times. Schools have a vested interest in getting diagnoses, because special-education funds are only available for those with a diagnosis. The reason Asperger's is being abandoned is because it was applied in exactly the way described above, until everyone realized it was a scam -- even the therapists who benefited the most. Now it's slated for removal from the next edition of the DSM, and further, the diagnosis criteria for autism spectrum is being reworked to prevent another epidemic of nonsense diagnoses such as we have just seen. > The odds that you receive a psychiatric evaluation against your will and be compelled into therapy are amazingly slim. On the contrary, it's an everyday occurrence, especially among children, who aren't mature enough to realize that psychologists aren't doctors. > Especially for something like 'autism-spectrum' disorders, where the majority of sufferers appear to be high-functioning. Yes, and that is the present problem area -- bogus diagnoses, using vague criteria that can be applied to nearly anyone, with obvious advantages to everyone except the patient. Mental health professionals, aware that autism spectrum diagnoses are out of control and no longer have any connection to reality, have joined an American Psychological Association task force charged with redefining ASD to stem the tide of nonsense diagnoses. One of those behind the redefinition effort (Dr. Fred Volkmar, director of the Child Study Center at the Yale School of Medicine) says of the diagnosis surge, "We would nip it in the bud."
- arethuza 14y agoThe Ancestor's Tale by Richard Dawkins looks at our ancestry right back to the start of life: http://en.wikipedia.org/wiki/The_Ancestor%27s_Tale http://en.wikipedia.org/wiki/The_Ancestor%27s_Tale It looks at a list of different species and then considers the most recent common ancestor we have with that species - fascinating stuff.
- chris_wot 14y agoSomeone has decided to downvote you. I really don't much like Dawkins (I'm a Christian), but this is very interesting. I hit the update button - your comment is a very worthy contribution to this discussion!
- lrem 14y agoAlso Christian here. I loved reading a few Dawkins books. Then I learned about his stance on religions... Well, I prefer if we just stick to science.
- andyjohnson0 14y agoSerious question: Did your learning about Dawkin's views on religion change your opinion of him as a scientist?
- lrem 14y agoIt didn't change my opinion of his science. It tore my feelings towards the person conducting it.
- Retric 14y agoI have the same gut reaction when I learn someone is religious/atheist. However, I after talking with most people what they say openly about religion vs what they say in private is often vary different. One of the most fascinating questions I think is 'how likely to do you think there is a universal creator?' Not based on what people say, but because it cuts though so much BS that people project.
- itsadok 14y agoThe point in the title is valid, but his answer to the original question seems misguided to me: in the time of the bible the only lineage that mattered is the paternal one. If your grandmother was King David's daughter that would not make you his descendant. Not in the eyes of your contemporaries.
- whatusername 14y agoExcept that Judaism has a form of Matrilineality so King David/etc were probably bad examples.
- tezza 14y agoMatrilineality is mostly from the Talmud , a collection of Rabbinic opinion. The Old Testament / Bible allows both parents to determine Judaism in the child. http://en.wikipedia.org/wiki/Matrilineality_in_Judaism http://en.wikipedia.org/wiki/Matrilineality_in_Judaism http://en.wikipedia.org/wiki/Talmud http://en.wikipedia.org/wiki/Talmud
- InclinedPlane 14y agoYes, and that person will be the inventor of some robot or other.
- acchow 14y agoWhat is the probability that a descendent carries even at least one gene from the "Most Recent Common Ancestor"? The human genome has only 20,000 protein-coding genes (which comprise 1-2% of human DNA). I'll be generous and use the 1% figure to assume that human DNA has about 2e6 "genes" (protein-coding or otherwise). After 100 generations: Probability any one gene comes from MRCA: 1/(2^100). Probability any one gene does not come from MRCA = 1 - 1/(2^100) Probability NO gemes come from MRCA = (1 - 1/(2^100))^(2^6) = 0.9999999999999999999999999999495129020658552444536494 Probability at least one gene comes from MRCA = 5.05 × 10^-29
- siganakis 14y agoI think that you have confused mutation with gene in your initial assertion. There is probably only a few percent of variation between all of your 2^100 ancestors genomes (the majority of whom will be related), so protein coding regions of your genome and your MRCA are actually likely to be very similar. Now if that MRCA had a specific mutation, the chances of your inheriting that specific mutation are probably low, but depend on that mutations prevalence in the population as well as whether the mutation is deleterious or not. 100 generations is very few in terms of changes within the genetic make up of a population under normal circumstances.
- hackinthebochs 14y ago>What is the probability that a descendent carries even at least one gene from the "Most Recent Common Ancestor"? If you think about it, its very nearly 100%. The fact that he is the MRCA means that a particular gene of his conferred an enhanced survival advantage. This enhanced gene is likely to exist in all of humanity currently living.
- spindritf 14y agoI may be missing something but it doesn't seem necessarily true. Our last common ancestor may have already died and we may not get another with all the divisions that exist, or space travel that may happen (ie. we don't and won't breed at random).
- chris_wot 14y agoSo in 3000 years we'll all be having sex with our relatives. Good to know!
- gazrogers 14y agoWe already are.
- chris_wot 14y agoThere's a cheery thought! Seriously though, what about if you marry someone from a different country? I'd imagine the chances are somewhat lower.
- takluyver 14y agoThe chances of what? They are still your distant relative, like everyone on earth. Someone from a different country is probably more distantly related, but unless they're a humanoid alien, they're still related to you.
- chris_wot 14y agoI guess there's not much point responding as the censor brigade came by and downvoted the hell out of my comment. It was a serious question, and I thank you for responding with a serious answer.
- freehunter 14y agoI don't think it was a censor bridge, it was a "this person didn't read the article" brigade. The point of the article was that everyone is related to everyone on a distant enough timescale. The person you responded to initially was making the point that everyone is your incredibly distant relative. Being in another country doesn't change that. 35 generations back, (mathematically) everyone has the same common ancestor.
- gazrogers 14y ago
- lifeisstillgood 14y agoI always get confused here between "Eve" and MRCA. AFAIK "Eve" is not what we are talking here - that is not as identifying one person who is the ancestor of all living people, but that if we go back to the time of David, then he, and 80% of everyone alive at the time (approx 1 million) MUST be ancestors of everyone alive now. That is some of his DNA and some of everyone elses DNA at the time is in me. That is pretty weird. The other thing that gets me is that till agriculture, it seems human population was stable at around 1 million. Then it started to grow to 1 billion by 1800. Freddie Mercury could sing to the whole population of earth in three concerts.
- damian2000 14y agoYes this is the key - people won't have just one ancestor but many millions.
- Cushman 14y agoI don't think the difference you're talking about is real. "Eve" is mitochondrial Eve, the most recent direct female-line ancestor-- the first human every woman can say was her mother's mother's mother's et cetera. There's a corresponding Y-chromosomal Adam; they probably lived 100-200,000 years ago, but not at the same time. But of course if you're descended from her, you're descended from her parents, and her mate's parents too; nobody came from just one person. Each one out of our millions of common ancestors is an Adam or Eve by the popular definition: Every human being alive is descended from them. If they had not conceived, no one currently alive would exist. There was never a biblically singular Adam and Eve.
- lifeisstillgood 14y agoSo, the first person who was the MRCA-with female lineage only, ie the earliest woman who was the female ancestor of all living people, was 100,000 years ago. But the earliest ancestor (female / male / mixed lineage) was only 3000 years ago. (i.e. the first, had to have daughters only, the second, more recent could have daughter then grandson then great-grandson etc) So, 3000 years before we can say anyone definitely was the ancestor of all, and there would be a lot of them. And 100,000 years before its female lineage. Then pretty much everyone is a common ancestor, back to plankton. And Dinosaurs!
- waterlesscloud 14y agoOr would have been, if genetic manipulation technology hadn't been invented.
- tinco 14y agoThe most important question is ofcourse, what do I have to do to be one of those common ancestors and have my dna be part of every human alive? Is it just having as many wives as possible like solomon and khan, or is there a better strategy?
- takluyver 14y agoIf you have several children, and raise them to well-adjusted adults who have children of their own, the chances are already very good. Assuming your average descendant has more than one child, and inbreeding is negligible, the number of descendants increases exponentially by generation. So the probability that none of your descendants in a given generation breed falls off rapidly. Of course, if you can father hundreds of children, that would also work. But you would probably run a much higher risk of being killed or imprisoned before you can spread your genes around much.
- nicky0 14y agoHave as many children as possible and encourage them all to breed prolifically.
- ctdonath 14y agoA friend is on her 14th. Get busy.
- Cushman 14y agoWell, your number of children is linear, but your number of descendants is exponential. For the CS students, what this means is that the number of children you have personally, even assuming they all reproduce, rapidly becomes immaterial next to the number of your descendants. The only reason having more children might be beneficial is if it significantly increases the odds that they personally, or their children successfully reproduce. If you have some other way of boosting those odds -- say, by being a successful parent to a smaller number of children -- that's just as good in the long run.
- derekp7 14y ago
- treelovinhippie 14y agoExcept that there is zero empirical evidence that the Bible figure "Jesus" actually existed...
- Tyrannosaurs 14y agoGiven that the article makes it clear in the first sentence that this is about more than the specific example of Jesus that's relevant how?
- daleharvey 14y agonot mentioning Jesus was never a common ancestor to all people, even in the bible. Adam and Eve were (and I guess Noah?)
- Tyrannosaurs 14y agoThe question is about the claim that Jesus was a descendent of David rather than people being a descendent of him.
- prawn 14y agoAlso, from where did Jesus get his Y chromosome?
- Tyrannosaurs 14y agoIf you take the bible literally and assume that God is the father then is the fact Jesus has a Y chromosome proof that God is a man?
- pitt1980 14y agoHowever, the question of the existence of Jesus as a historical figure should be distinguished from discussions about the historicity of specific episodes in the gospels, the chronology they present, or theological issues regarding his divinity.[360] A number of historical non-Christian documents, such as Jewish and Greco-Roman sources, have been used in historical analyses of the existence of Jesus.[357] The large majority of modern historians agree that Jesus existed and regard events such as his baptism and his crucifixion as historical. http://en.wikipedia.org/wiki/Jesus#Existence http://en.wikipedia.org/wiki/Jesus#Existence
- jsemrau 14y agoYou better hope it will be me!
- cs702 14y agoBy the same mathematical logic, almost everyone in the US today is a descendant of European royalty -- even people who are predominantly African or Native American. Similarly, everyone in the US with primarily European ancestry is a descendant of both Muhammad, the founder of Islam, and Charlemagne, the so-called "Father of Europe." These claims were made by an entertaining article written 10 years ago in The Atlantic, "The Royal We," which covered the mathematical study of genealogy and is a good companion to the BBC piece: http://www.theatlantic.com/magazine/archive/2002/05/the-royal-we/302497/ http://www.theatlantic.com/magazine/archive/2002/05/the-roya...
- arethuza 14y agoNice line from that article: "Just as we are descended from most of the people alive on the planet a few thousand years ago, several thousand years hence each of us will be an ancestor of the entire human race—or of no one at all."
- bstpierre 14y agoI've actually traced my ancestry back to Charlemagne. It's an interesting exercise. Some of my links are not very well substantiated, but the dozen or two generations from Charlemagne forward are fairly well documented, depending on how many of your ancestors were bastard children of some horny nobleman. (Of course there are countless poor peasant farmers between now and then as well.)
- te_platt 14y agoI've also traced my ancestry back to Charlemagne. It's good fun but it's not the iffy documentation that is the main problem. It's the milkman effect. In talking with a researcher at a genetic genealogy center he said that around 10% of the population has a different biological father than they think they do.
- pacaro 14y agoI'd love to see this either substantiated or debunked - I've seen this claim made and refuted many times, but have never found a truly reliable source.
- placidex 14y agoJon Kleinberg, Professor of Computer Science at Cornell University on the pigeonhole principle: http://edge.org/response-detail/2890/what-is-your-favorite-deep-elegant-or-beautiful-explanation http://edge.org/response-detail/2890/what-is-your-favorite-d...
- bluedanieru 14y agoNot if people alive today are still alive in 3000 years, which isn't terribly likely but not wholly out of the question either.
- lifeisstillgood 14y agoIf they had kids today, and then stayed alive, it would work out pretty much the same. Except it would be fairly crowded.
- mmcconnell1618 14y agoMathematical proof why people get addicted to genealogy. They are almost certain to find they are related to someone famous if they go back far enough. It makes perfect sense why companies that provide genealogy research have no problem finding customers. The lure of finding out that you are as awesome as you thought you should be by way of royal bloodline, etc. is a pretty powerful market force.
- SoftwareMaven 14y agoMy wife was playing around with the LDS Church's online genealogy tool and, not surprisingly, found European royalty in her ancestry. I don't think I quite succeeded at explaining that pretty much everybody would have those. For me, far more interesting than who is in there is the path things took between me and that royalty.
- Dn_Ab 14y agoWhat I am more interested in is: will someone who is alive in 3000 years be a common ancestor of all humanity?
- nihilir 14y agoQuoting the article: "And one can, of course, project this model into the future, too. The maths tells us that in 3,000 years someone alive today will be the common ancestor of all humanity. A few thousand years after that, 80% of us (those who leave children who in turn leave children, and so on) will be ancestors of all humanity. What an inheritance!"
- Dn_Ab 14y agoHeh =). But what I mean is something like, will there be someone alive in 3000 years that is about 2000 years old.
- snowwrestler 14y agoPerhaps this person: Person Who Will One Day Become Warlord-Ruler Of What Was Once Nebraska Born In Omaha Hospital http://www.theonion.com/articles/person-who-will-one-day-become-warlordruler-of-wha,27406/ http://www.theonion.com/articles/person-who-will-one-day-bec...
- deleted 14y ago[deleted]
- talaketu 14y agoIt's a consoling thought for the childless... almost all the branches of the vine end.
- nihilir 14y agoI think you misread (or didn't read the entire article). The article states that the majority of the "branches" will live as long as humanity itself. I am currently childless and did not find this a consoling thought (quoted from the article): "In fact about 80% of the people at that time in the past will be the ancestors of everyone in the present. The remaining 20% are those who have had no children, or whose children have had no children, and so on - in other words, people who were genetic dead-ends. [...] A few thousand years after that, 80% of us (those who leave children who in turn leave children, and so on) will be ancestors of all humanity. What an inheritance!"
- hackinthebochs 14y agoNo, it is true that eventually most branches will end. It's just on the timespan of 3000 years, 80% of the population will likely be a common ancestor. But if you extrapolate back far enough, there will be one and only one. The only way branches can survive forever is if you assume that all genes have essentially the same chances of survival. This obviously isn't true. Even the smallest enhancement will quickly spread throughout the population. I am curious when the most recent unique common ancestor of humanity existed. Would we consider him human now or something in between?
- wensheng 14y agoI don't think so. People will stop having offsprings (and even sex) well before that because they are immortal, even if they die, they can be resurrected because they have copies. Provided, human race doesn't get destroyed by itself or AI.
- Claudus 14y agoSo it seems that recessive traits, like blue eyes, will likely be bred out of humanity in relatively short order. At least until full blown reproductive genetic manipulation comes into effect.
- aidenn0 14y agoYou need to (re)read Mendel. Recessive traits and dominant traits stay at a constant fraction within a population (absent selective pressures).
- hackinthebochs 14y agoThat's assuming sexual selection doesn't play a role.
- herounworship 14y agoProbably this guy http://www.cbs42.com/content/localnews/story/Former-Alabama-Politician-Sperm-Donation-Scandal/iLCA4bN-Pkq1cWEQ3CO7AA.cspx http://www.cbs42.com/content/localnews/story/Former-Alabama-...
- samspot 14y ago> That's why everyone alive in the Holy Land at the time of Jesus would have been able to claim David for an ancestor. This really threw me for a while, as it seemed to be an obviously false statement. Until I realized the author had switched contexts on me: Jesus claimed male ancestry, but this statement is including ancestry from both male and female lines. So it seems overall believable, however I still see many provably false assumptions in this article. * The population of the Holy Land was a constant 1 million people for 35 generations. Assumes no population growth. (false) * No imigrants (false, see next bullet) * No intermarrying with other cultures (false, because this intermarriage is often cited in the Bible as a reason people turned to other gods) > More specifically, imagine the simplest case of a population of a constant size - say a million (the approximate size of the Holy Land at the time of Jesus). I'm just quoting this to show that the author asks us to assume a constant size population I'm certain that there were thousands of people in Palestine that could have claimed an unbroken ancestry from David. But based on all the flaws in this article, I don't trust the assertion that everyone in the area can claim an unbroken line (even including female ancestors).
- msg 14y agoIf you guys have not read Galapagos by Kurt Vonnegut (finished it this week), you should. Its about the evolution of the human species over the next million years turning on very specific events in Ecuador in the year 1986, and the common ancestor of all future humanity. In his unique style, of course.
- RockofStrength 14y agoThat one is Vonnegut's sleeper masterpiece - the choice of narrator was especially clever. How can you have a narrator narrate a million-year-spanning story? Vonnegut figured it out.
- everlost 14y agoAnother good read is "One Hundred Years of Solitude" by Gabriel Garcia. Its about the birth and death of an entire family line, flowing through the wars, migrations and incest that revolved around it (atleast thats my interpretation :)).
- lutusp 14y ago> In 3000 years someone alive today will be the common ancestor of all humanity The title is very misleading. It's not true about any single person, unless there's a species bottleneck with only one survivor, and then there's a practical problem. It would be more accurate to say that all those living 3000 years from now will have their genetic roots in all those living in the present. But if that had been the headline, no one would read the article. How about this: "In 3000 years everyone alive today will be the common ancestor of all humanity". True, but not very exciting.
- deleted 14y ago[deleted]
- hackinthebochs 14y agoThe title is accurate. The article states explicitly that 3000 years ago the common ancestor of all of humanity existed. It's just that 3000 years ago wasn't the point where one and only one common ancestor existed; some 80% of the population may have carried that distinction.
- lutusp 14y ago> The title is accurate. The article states explicitly that 3000 years ago the common ancestor of all of humanity existed. The title -- "In 3000 years someone alive today will be the common ancestor of all humanity" -- is not accurate. There was no single "common ancestor", because modern humans owe their genetic inheritance to multiple sources. This will be true in the future as well.
- hackinthebochs 14y agoI'm not sure I understand the relevance of your point. If you're saying that there is no single common ancestor, but multiple common ancestors at the timespan of 3000 years, then yes that is true. But that doesn't invalidate the fact that any of them is the (perhaps better stated as "a") common ancestor.
- dkroy 14y agoHaha, I cannot believe that they could not get a better picture of the guy in the article than they did. Picture: http://news.bbcimg.co.uk/media/images/62401000/jpg/_62401882_yanwong_bbc.jpg http://news.bbcimg.co.uk/media/images/62401000/jpg/_62401882...
- T-hawk 14y agoThis article makes the mathematical point, but deliberately ignores social reality. Yes, 100 generations is sufficient time for the premise to be possible, to fully propagate genes from every ancestor to every descendant. But reality doesn't work that way. Human population groups breed within themselves. Mating pairs are not chosen at random from the entire human population. Consider all the remote groups that would have to be covered to satisfy the assertion. Someone alive today would have to become a common ancestor of every Lapp in Finland, every Aborigine in Australia, every Inuit in Nunavut, every Maori of Polynesia, every Falklander, every North Korean, and countless more groups that barely have any contact with the world community, let alone interbreeding. (And maybe we'll actually launch a Mars colony or interstellar generation ship, literally making it impossible.) The article does mention this very offhandedly, inserting the clause "If people in this population meet and breed at random". But that antecedent is plainly false so the conclusions are not defensible.
- TravisDirks 14y agoI doubt this is as big a problem as you think. If you have any interbreeding at all the general conclusion holds. I would guess that even extremly low estimates of interbreeding rates wouldn't change the result much.
- brlewis 14y agoNote that the article never specifically talks about propagating genes, just about being an ancestor. No matter how many generations you go back, there will be at most 46 ancestors in that generation whose genes a descendant has, and only one ancestor's mitochondrial DNA.
- d2vid 14y agoNot true regarding 46 ancestors - chromosomal DNA is swapped between the homologous chromosomes during meiosis: http://en.wikipedia.org/wiki/Meiosis#Prophase_I http://en.wikipedia.org/wiki/Meiosis#Prophase_I You are correct about mitochondrial DNA.
- Shorel 14y agoWe don't have conquerors and kings anymore, in most parts of the world. The common ancestor would probably have to be the ancestor of a very successful nation that would rule (a big part of) the world, and no current world ruling nations let their governors reproduce at will, like they did in the past. Currently the world is full of Genghis Khan descendants, but also, there are no Genghis Khan equivalents anymore. Simply remember the Monika Lewinsky scandal.
- TravisDirks 14y agoVery interesting! If I didn't misread, a better title would be "In 3000 years almost everyone alive today will be a common ancestor of all humanity." From the story: "In fact about 80% of the people at that time in the past will be the ancestors of everyone in the present. The remaining 20% are those who have had no children, or whose children have had no children, and so on - in other words, people who were genetic dead-ends." This puts a whole new perspective on the often quotes statistics about Genghis Khan's progeny.
- erikpukinskis 14y agoThe concept is totally flawed, because the probability of inbreeding goes up as you go back in the generations, so: Probability your parents are the same person: 0 Probability one of your grandparents is the same person (i.e. your mom's mom is your dad's dad's wife): very low But then you get up to the point where you have 10k or 10m ancestors and those numbers start to skyrocket.... especially given how relatively geographically constrained we are. So if you go back 3000 years, you'll have whatever 200 million (whatever the global population was in 2000 B.C.) ancestors. But that number will be chock full of "repeats". In fact you might only have 20 million "unique" ancestors in that era. You'd need to model migration to actually figure out when you could reasonably expect that everyone would be somehow descended from you. But even if you completely buy in to the premise of the article, they still get the analysis wrong. It's not that someone will be the common ancestor, it's that everyone¹ will be a common ancestor of all humanity. ¹ who breeds and whose children breed, and their children breed...
- saraid216 14y ago> It's not that someone will be the common ancestor, it's that everyone¹ will be a common ancestor of all humanity. Yes, that's actually stated very pointedly in the article.