News24

Cavemen sex gave humans immune boost

2011-08-26 08:29

Washington - Sexual encounters with archaic humans like the Neanderthals produced children who inherited key genes that have helped modern humans fight illness and disease, said a study said.

"The cross-breeding wasn't just a random event that happened, it gave something useful to the gene pool of the modern human," said Stanford University's Peter Parham, senior author of the study in the journal Science.

Equipped with knowledge of the genome of the Neanderthals and the Denisovans, of whom a tooth and a finger bone were discovered in a Russian cave in 2010, researchers scoured the data for hints of what genes crossed over.

Scientists already knew that about 4% of Neanderthal DNA and up to 6% of Denisovan DNA are present in some modern humans.

This study took a close look at a group called HLA class I genes which help the immune system adapt to fight off new pathogens that could cause various infections, viruses and diseases.

Rare

Researchers traced the origin of one type, HLA-B*73, to the Denisovans, who likely mated with humans arriving in West Asia on their way out of Africa. The variant is rare in modern African populations but is common in people in west Asia.

"We think this had a lot to do with the pathogenic environment in different parts of the world," said Laurent Abi-Rached, a French researcher and lead author of the study.

"When modern humans came out of Africa, they were going into a new environment. This gave them an advantage. It was a rapid way of acquiring defence," he said.

These ancient HLA genes have multiplied among modern populations and are seen in more than half of Eurasians today, said the study.

"If canoodling was the whole story, that's an awful lot of genes," said Milford Wolpoff, a paleoanthropologist at the University of Michigan who was not involved with the study but said he supported its findings.

"This is called multiregional evolution. We have been talking about this for 30 years," he said.

"Many of the genes we find are doing something useful. The only answer for that is natural selection."

Latest findings

Neanderthals died off about 30 000 years ago. They and the Denisovans shared a common ancestor with modern humans about 400 000 years ago.

Modern humans eclipsed these ancient cousins when our contemporaries began expanding into Asia and Europe from Africa about 65 000 years ago.

Some mating must have occurred, given the evidence that lingers in our DNA, but even the latest findings have shed little light on the nature of those relationships - whether violent or consensual, short or long-term.

"Even though there was probably interbreeding, that was not necessarily very frequent," said Abi-Rached.

"But it has played a major role in shaping modern human immunity."

Abi-Rached said he hopes further research will reveal more about the role that the immune genes may have played in protecting those who survived but also their role in autoimmune diseases that humans face today.

The work of studying the legacies left by ancient ancestors in our bodies could lead to new pathways for treatment of modern diseases, which has researchers excited about the potential of the emerging field.

"Most of the money in genetics is related to diseases," said Wolpoff.

"Paleoanthropology is just like politics. You follow the money."

Comments
  • jjhvan - 2011-08-26 08:37

    Spyker vandag en oor 65000 jaar weet almal dit. Tsk tsk.

      JohannV - 2011-08-26 08:43

      I just love how they pluck these numbers out of nowhere: 30 000 years, 400 000 years...

      CapeTownJunk - 2011-08-26 09:17

      @JohannV: They don't pluck these numbers out of nowhere. DNA is a gold mine of genetic information, and scientists have a huge arsenal of tools to extract meaningful data from DNA. Nobody's asking you to understand it - but if you're going to dispute these numbers, you'd better have more solid evidence than your own personal unwillingless to trust scientific expertise.

      Kudubul - 2011-08-26 09:21

      They call it science.Didn,t you have the subject at school?

      Nepster10 - 2011-08-26 11:02

      @JohannV. Its called Radio carbon dating. very accurate. Half life of radio active carbon 13 is used to determine the number of years. Basically when the organisms died they died with the carbon 14 isotopes in their bodies. Not gonna go deeper lest it will turn into a physics lecture.

      Tom - 2011-08-26 14:18

      Nepster: I do not profess to know much about carbon dating just what I have read and the last article I read, also by a group of "know it alls", said that carbon dating is not an accurate method of find out the age of anything. In fact the article went on to say that these same scientists dated a living seal to be about 175mil yrs old. Please tell me who do I believe now?

      Lacri - 2011-08-26 14:23

      Tom, can you link to the article?

      Tom - 2011-08-26 15:01

      Just type accuracy of carbon dating on google... or http://www.talkorigins.org/indexcc/CD/CD011_4.html Sincerest apologies the seal was dated at 1300yrs, still very much out.

      Lacri - 2011-08-26 15:56

      Thanks Tom. The point of the article seemed to be that the so-called "reservoir effect" is known and understood, and that carbon dating results are accordingly not accepted in these circumstances. Excluding a method of measurement in circumstances where it is known to be unreliable surely speaks well for the reliability of the method of measurement where it is used?

  • CynicBelieve - 2011-08-26 08:37

    That will make a weird movie title: "Debbie does the Neanderthal tribe"

      darkwing - 2011-08-26 09:25

      Deep throat in the jungle.

      claudevn - 2011-08-26 09:48

      LOL Funny stuff dude!

  • jovie - 2011-08-26 08:43

    Absolute Nonsense!

      PrinceCharle - 2011-08-26 09:06

      Ah but can you prove that it's absolute nonsense? ;-)

      OnlyaGinger - 2011-08-26 09:09

      Oh wise sage, what makes this nonsense? Just because it doesnt agree with your narrow viewpoint of he worldm does not make the scientists wrong, please feel free to state your qualifications on the subject, apoarently you know something we dont

      zaatheist - 2011-08-26 09:42

      Evolution is a simple fact. We can choose to remain ignorant of it, we can stick our fingers in our ears and refuse to think about it, we can even rail against it and shout and scream that it is not allowed to be true. But facts are facts, and will not go away just because we don't like them. We don't get to vote for our preferred method of having come into existence as a species, any more than we can choose to have been delivered by stork rather than conceived and born in the usual way. - Paula KIrby

      Modicum of Reason - 2011-08-26 09:54

      @zaatheist: Your posts are always so eloquent and you manage to really hit the point home, I tend to get a bit worked up at these idiots sometimes.

      zaatheist - 2011-08-26 10:47

      @Modicum of Reason The eloquence is not always mine but I do attribute what is not my own. Paula Kirby writes for the Washington Post and is a brilliant writer and commentator.

      GLY - 2011-08-26 13:35

      zaatheist. I can accept that evolution is a theory but not a fact. To quote modicum of reason "the acientific way is to "Postulate, theorize, test, observe, confirm/refute, repeat." If I follow this principle scientists would have had to observe the evolutionary processes, which they say took thousands or millions of years and it would have also had to be repeated. These two steps could not have been completed hence a break in the procedures required for proof.

      Lacri - 2011-08-26 13:58

      GLY, what do you understand by the word "theory"? Gravity is also a theory, as are many things accepted for all practical purposes as fact. I also take issue with your statement that scientists would need to observe evolution for millions of years. Is it necessary to observe an actual atom or is it sufficient to observe the chemical and physical processes that lead to the inescapable conclusion that the atom exists? In any event, it is not necessary for many years to pass for evolution to take place - only many generations. The observation of short-lived organisms, especially single-cell organisms, has indeed revealed evolution in action and a great deal of fascinating work has been done in this line if you're interested in it.

      CapeTownJunk - 2011-08-26 14:11

      @zaatheist: You wouldn't by chance have picked up that quote via Pharyngula, would you?

      zaatheist - 2011-08-26 14:25

      @CapeTownJunk Sure!

      GLY - 2011-08-26 14:28

      zaathiest I was merely quoting modicom of reason.

      GLY - 2011-08-26 14:30

      @lacri.Gravity is a fact because the effects of it can be seen and measured. The reason for it may be theory but the fact that you are on earth is because of gravity.

      CapeTownJunk - 2011-08-26 14:35

      @zaatheist: Greetings from one habitual lurker over at PZ's!

      Lacri - 2011-08-26 15:02

      Precisely. The effects of evolution can be seen and measured. The reason for it may be theory but the fact that you are on earth is because of evolution.

      GLY - 2011-08-26 16:42

      @lacri you are applyinga THEORY evolution as being fact. There have been so many mistakes in the past that science constantly corrects. e.g. please explain Piltdown man! The whole method of dating fossils is inaccurate. Carbopn 14 dating estimate that liofe could only have existed up to 50 000 years ago. Using the half lives of other radioactive isotopes which have been observed over a period of 100 years and then predicticting their behaviour back into billions of years is statisticall unreliable. If I surved 100 people and then said that that was representative of a population group of 1 000 000 my conclusions would be regarded as irrelevant and yet this is whay scientists are trying to tel is is now fact. I don't think so!

      Modicum of Reason - 2011-08-26 17:21

      @GLY: You do not understand the meaning of theory. and you don't understand the scietific process and I realise we are not going to convince you of this. Carl Sagan said it best. "You can't convince a believer of anything; for their belief is not based on evidence, it's based on a deep-seated need to believe." You cannot accept evolution, your fairytale forbids it. Your mind is too clean(it's been washed). It's a pity actually. When you realise that when you die that's the end of it, that is the moment you realise how precious life is and you realise how every second you have here is in your control. It's truly an epiphany and I wish everyone could experience it. True freedom. Evolution is the "how are we here?", the "why are we here?" is your potential, you control it and you have only yourself to blame.

      CTScientist - 2011-08-26 17:55

      @ GLY: Y'all need to get off this radiocarbon dating hate festival. Jesus. Radiocarbon dates are calibrated with dendrochronological dates up to approximately 11.9ka. After this period various other inter-disciplinary methodology (such as ice cores, coral rings, as well as other dating techniques) are employed to calibrate radiocarbon dates. The effective range of radiocarbon dating is from an approximate 200 to 40 000 years ago. However, this date can (and has) been pushed upwards of circa 50k if special, but expensive and time consuming, lab preparations are made. Various problems in carbon dating have been described in multiple journals and these are well understood. Specimens which are subjected to problems associated with the reservoir effect, for instance, are no longer used. In addition to this, the various plateaus in calibration dating are also dealt with by a variety of sound methodologies. Remember that a lot of creationist bollocks posted online concerns issues with beta counting and not modern AMS methods. Furthermore, you need to understand that radiocarbon dating is only ONE method employed by scientists. Optically stimulated luminescence and thermoluminescene dating techniques have proven to be huge successes in various instances, and potassium-argon dating is a household name in east Africa. These are only some of the absolute dating methods which are employed in tandem with relative dating techniques, further consolidating the archaeological record.

      Spoedvark - 2011-08-26 19:30

      Paula's scorching article can be read here: http://www.washingtonpost.com/blogs/on-faith/post/evolution-threatens-christianity/2011/08/24/gIQAuLVpbJ_blog.html The lady rocks!

      dogue - 2011-08-28 02:42

      Spoedvark, she rocks indeed! I particularly liked the end: "Willful ignorance is a choice; evolution is not."

  • SoulDaddy - 2011-08-26 09:08

    dis min maar dis in

  • Fredster69 - 2011-08-26 09:24

    Maybe we were just born with key genes that fight illness and disease

      MBossenger - 2011-08-26 10:19

      Shouldn't omniscient god have done his design a bit better and not created that pesky little critters that kill us and make us sick?

      GLY - 2011-08-26 13:27

      Mbossenger, The original creation was perfect. The problem came when God cursed the Earth after man sinned. I guess the next issue will be that "I dont believe in the Bible".

      Lacri - 2011-08-26 13:55

      Can you explain to me why people like Native Americans lacked resistance to diseases that they had not encountered before Europeans landed in the Americas? In fact can you explain to me why disease exists at all?

      Lacri - 2011-08-26 13:57

      That was in reply to Fredster69, incidentally.

      tsotsi420 - 2011-08-26 14:01

      @ GLY - well then that wasn't very nice of God, what happened to forgiveness ? or is it "not until you say sorry" (foot stamping)? If it's God's place to forgive then why did the Inquisition and medieval Church (who basically wrote the bible) burn people alive for, in some cases, merely dressing the wrong way ? Why does the church not burn people alive anymore ? Could they have evolved beyond it ? Do you see a pattern...

      GLY - 2011-08-26 14:46

      @tsotsi420. The forgivness of God came later but it can only happen when repentance is evident.This is an issue that goes deep and is discussed in length in Christain churches. However seeking forgiveness does not cancell out the consequences of sin. e.g. If someone kills a person the victims family and God can forgive her but she has to live with the consequences of her actions e.g. Carla Faye Tucker . I get the impression that you are likening the "evolution" of Christian belief to that of Darwins ? theory. If you want to continue on this line I must remind you that you are judging the actions of the followers of Christianity i.e. the inquisition. I could say that football is barbaric because I saw some football holigans breaking windows and looting shops. this would be untrue but many non believers do not seperate the actions of Christs followers from Christ.

      Modicum of Reason - 2011-08-26 17:33

      @GLY: Yes but without christianity there would be no inquisition just like without football there would be no football hooligans. Do you see a pattern...

  • cromagnon - 2011-08-26 09:29

    As far as I know, when two organisms produce fertile offspring, they are the same species(A horse and an ass produce a mule, which is infertile, because a horse and an ass are different species) So, if a Sapien and a Neanderthal can produce fertile offspring, that would mean they are the same species. Since Sapien and Neanderthal reflects the species name, that may have massive consequences for paleoantropologie since one of the species name should change....

      lory - 2011-08-26 10:16

      I am no specialist, but I think the species defenition has chanced a bit from this simplified general view.

      Lacri - 2011-08-26 10:16

      Not so, cromagnon. Firstly, the classification of species is not quite as simplistic as you've put it. Members of different species USUALLY do not breed, and if they do then their offspring USUALLY are sterile, but this is not an invariable rule. Different species of wolves, for example, are able to breed and produce fertile offspring, as are wolves and coyotes. Secondly, both modern humans and neanderthals belong to the genus and species Homo sapiens. Modern humans are members of the sub-species Homo sapiens sapiens, Neandertals of the sub-species Homo sapiens neanderthalis.

      cromagnon - 2011-08-26 11:06

      Yes, I made a pretty big generalisation! I will study up on species a bit :-)

      CTScientist - 2011-08-26 18:03

      @ Cromagnon Homo sapiens and Homo neanderthalensis did not endure periods of isolation long enough for founder effects to take place (Anton, 2004). Homo sapiens regularly came into contact, and probably bred with, Homo neanderthalensis in the Levant at various instances prior to the Out of Africa excursion circa 65ka. Overwhelming archaeological evidence supports this view. Geneticists also maintain that only a single breeding event in each generation is required to keep two separate species in the same genus genetically compatible, insofar that they can produce fertile offspring. My last point. And the main one. All non-African humans ON THE PLANET have up to 4% Neanderthal DNA stored in their own mitochondrial DNA. Bang. :P Enough said. The above should clarify your confusion.

      CTScientist - 2011-08-26 18:21

      @ Cromagnon In any respect, the children of such offspring retained anatomical features in line with modern Homo sapiens. For all intents and purposes, the offspring were not sufficiently different from the earliest Africans that left sub-Saharan Africa for there to be any need to give these offspring a new species name. There are no speciation events, in other words. Besides, these two species were so very similar genetically (not enough time since separation) that we would not expect exceptional anatomical or biological changes beyond those described in the article. 4% is both a lot of DNA, as well as very little.

  • Geraldo Mc phu - 2011-08-26 09:29

    Everytime I read these tales I know that it's all laughther and more laughter for me and my day just brightens up...can't wait for 16:30 to grab myself a beer ...

      Justin.A - 2011-08-27 09:30

      Yes all the crazies who think the world is 6000 years old and that somehow the entire scientific community just made these things up are hilarious. I love it!

  • s209004284 - 2011-08-26 09:42

    Bull Shit Poeple who think these stuf up are really bored

      lory - 2011-08-26 10:08

      Understanding science takes some IQ, difficult for people to grasp......

      dogue - 2011-08-26 10:42

      You have to be really cynical to think this is made up. These people spend their whole lives, their careers, studying this, sharing all their knowledge, anyone can verify it (indeed, they do!) and refute it...

      Modicum of Reason - 2011-08-26 10:48

      The scientific method: Postulate, theorize, test, observe, confirm/refute, repeat.

      Olavin - 2011-08-26 12:07

      More like Postulate, theorize, test, refute, manipulate results, confirm, publish.

      Modicum of Reason - 2011-08-26 12:12

      @Olavin: Oh so you witnessed this outrageous claim? You should come forward with this blatant evidence against the scientific method. I wonder how the world could of overlooked this obvious fact that you have presented. Someone give this man a bells.

      GLY - 2011-08-26 13:24

      Modicum of Reason. I wonder who did the observing of cavemen having sex.

      dogue - 2011-08-26 14:30

      GLY, they went in a time machine. Serious, there's no time machines, so finding fossils is the only proof we have. You can deduce certain things without being there. For example, if a white couple has a black baby, do you need to have seen the conception act in order to come to the conclusion that she cheated?

      Justin.A - 2011-08-26 16:23

      //I wonder who did the observing of cavemen having sex.// They traced the origin of genes! Did you even read the article?

      GLY - 2011-08-26 16:46

      @Justin. Did you even read my other posts. I was equating the scientific steps quoted by modicum of reason and applying them to the article.

      Modicum of Reason - 2011-08-26 17:29

      @GLY: again, you simply have not researched enough on the scietific process and the meaning of theory as it is applied here. I undestand that you think you are making a fantastic point, but the truth is you are not and sadly you look like an idiot to boot.

      CTScientist - 2011-08-26 18:09

      @ s209004284: The people who 'think' these things up are Academics who constitute the top 1% of the planets smartest people. They've studied and dedicated years of their lives to be able to truly uncover the past. They do not get paid as much as priests but they sure as the seven hells provide clarity where none existed before. Science is truly a beautiful and rigorous discipline. @ GLY: You latch onto a word you hardly comprehend. We do not 'observe' light. We 'interpret' light frequencies. We do not see 'atoms', we construct technological innovations to show us what they look like. We do not see stars, but only their light from millions of years ago. We do not observe, in the extant sense of the word, anything of consequence. However, we can infer various aspects of the universe because we're smart enough to realise that there are many ways to observe the unknown. DNA analysis, as well as use of the archaeological record, allow us to observe many aspects of the evolutionary trajectory our genus has been on for millions of years.

      Justin.A - 2011-08-27 09:26

      //Did you even read my other posts. I was equating the scientific steps quoted by modicum of reason and applying them to the article// Yes. Postulate, theorize, test, observe, confirm/refute, repeat Notwithstanding the other steps you have omitted, may I draw your attention to "confirm/refute" which requires peer review. As the article in question reports over a publication in the journal science, you no doubt have published your findings refuting the original source in there and will be forthcoming with links, no? You may also notice that observe comes after "Test", which implies qualified people did some work here, not just "look at stuff". Which brings me back to my original point: the test was done on a genetic level and observed to show a the origin of certain of our genes come from Denisovans etc. This is how the conclusion was reached. All of this is well within your grasp if you had read the article, and bothered to do some research on the subject.

  • ByTheBeach - 2011-08-26 09:43

    "...said a study said." Doesnt anyone proof read these articles before they are posted?

      lory - 2011-08-26 10:12

      Its based on genetics. The basics for all these studies are applied to produce better crops, more meat etc. for u to eat.....u accept it to be able to have enough food, but think it does not aplly to all Homo species as well.....after all we are only a hairless big ape........

  • zule - 2011-08-26 09:47

    It is always interesting to read these types of accounts...and to learn more about our "beginnings"

  • Anton - 2011-08-26 10:24

    Does it count if you dress up like a caveman?

      daaivark - 2011-08-26 10:49

      Only if you have your eye on a cute little neanderthal, lol.

  • CTScientist - 2011-08-26 18:12

    This will not revive multiregionalism, Wolpoff. That ship has sunk many a year ago. Aspects of the theory may have particular merit, but as a whole, it fails to explain the various expansions of a fairly homogeneous population of Homo sapiens from sub-Saharan Africa.

      bmpdragon - 2011-08-26 19:35

      True, CTScientist, but if you have gambled your whole academic career on a largely discredited hypothesis, as Wolpoff has, you too would be clutching at straws...

      CTScientist - 2011-08-26 23:13

      @ Bmpdragon: No. I would not. There is no excuse for turning into a Wolpoff or Klein. Scientists should never stick to a particular theory because of their personal feelings, professional career, and/or ego. If they can't say "I was wrong" then who the hell can? We expect science to progress. That means we will be wrong sometimes! But we have the necessary reason to understand that that ought to be okay.

      CTScientist - 2011-08-26 23:14

      But I do see your point, nonetheless..

      bmpdragon - 2011-08-27 00:15

      Ah, CTScientist, don't be so Utopian about science and academia: we both know how it works... the grants, funding, tenure, citation listings, etc. A lot of big fish in very small ponds (take the MIT Linguistic Functionalist and Innatist clique for example) fighting over limited resources. Hypotheses are like babies and one certainly doesn't want an ugly baby! Even though there should be a dispassionate and objective stance towards hypotheses, most academics take their own ideas very personally. Wolpoff is fighting for his academic career and legacy. Nonetheless, I too, see your point... ;-)

      CTScientist - 2011-08-27 08:20

      @bmpdragon: I suppose we should attempt to find some common ground, write a manifesto, and then revamp the discipline. ;)

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