The latest edition of the journal Cell has a report that some people from the Max Planck Institute in Germany have sequenced a whole Neandertal genome.
Here is the report:
http://www.physorg.com/news137334959.html">Complete Neandertal mitochondrial genome sequenced from 38,000-year-old bone from PhysOrg.com
A study reported in the August 8th issue of the journal Cell, a Cell Press publication, reveals the complete mitochondrial genome of a 38,000-year-old Neandertal. The findings open a window into the Neandertals' past and helps answer lingering questions about our relationship to them.
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This blurb doesn't say much, so the astute reader may want to go here for further information. The article came from the British journal Nature, and has some comments, though not much more explanation, about the genome.
My own thoughts about this paper go like this:
I don't think there's any doubt in anybody's mind that Neandertals were a distinct population Their anatomy alone, whilc basically similar to ours, has some pretty "distinct" features, like their browridges and the "buns" on the bakc of their skull, and the shape of those skulls, though at least one worker in the field suggests that their brains were arranged pretty much like ours(he deduced this from endocasts). They also had denser bones and more muscle attachments, than "modern" people.
But what does all this really mean? The geneticists who pulled together their "Neandertal genome", admit themselves, that there need to be more sequences done on specimens from other Neandertal populations. And they admit that while certain proteins they sequenced(if I understand this study correctly), have somewhat different DNA sequences, they apparently functioned no differently from "ours">
Given that Neandertals are the best known of all prehistoric humans(other than early "modern" ones), and had the fortunate(for us) habit of burying their dead with some regularity, there are more Neandertal fossils lying around, waiting to be sequenced by these methods, than any other prehistoric human fossils. Furthermore, they were the first non-"modern" humans ever discovered, so they have been scrutinized in various ways, for a little over 150 years.
One would think that, since tremendous changes in our understanding of inheritance, and the acceptance --- by most educated people --- that evolution has taken place, one might think many of the questions surrounding the rise and demise of Neandertals would have been answered. But they are basically the same old questions, and there seems to be a tendency for a lot of people to assume, just as they assumed back when the unfortunate La Chapelle aux Saintes fossil was discovered, that they were basically "different" and "not like us at all". But what archaeological evidence there is, seems to suggest that while they were(apparently) a decidedly small population, they also had pretty much the same behaviors and responses that "modern" humans do, to a variety of things.
Because of this, many people are faced with the dilemma of trying to figure out how much "like" us, they were, given that there seem to have been some populations of prehistoric humans with "mixed" ancestry --- long after there were any Neandertals --- and so far, none of these questions have been settled to anybody's satisfaction. This study is a step in some direction: they appear to have been "different" all right. And there are plenty of people who do not want to consider that there might have been any connection at all, between Neandertals and "modern" humans. These people latch on to studies like this, with the tenacity of hungry wolves trying to make meals out of the nearest deer, and insist that Neandertals were a totally "separate species". But what constitutes speciation depends on a lot of factors, for evolution, human and otherwise, is a complicated, messy business. Since no one has yet satisfactorily answered how much "difference" actually constitutes speciation(other than the inability of two separate organisms to mate and produce fertile offspringa), what we are left with, is essentially judgment calls as to what these ki8nds of differences "mean". Since I'm a writer writing a Great Medieval Science Fiction Masterpiece With Neandertals, I can't claiim to know what these differences "mean", though I have my opinions. Be that as it may, I think this study will probably raise even more questions about Neandertals, their relationship(if any) to "us", and what "happened" to them, than it ever can answer. And the arguments surrounding these questions, will go on for a long, long time after numerous other studies(which probably won't answer these questions either), have come and gone.
Anne G
Redheaded Neanderlady
This is a photoshopped version of something I found in National Geographic about the time I started researching
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5 comments:
Good to have another view of the research. Dienekes and Mathilda both have posts on the subject.
I agree that many people jump on mitochondrial evidence like wolves. MtDNA tells us very little about species relationships when the species are closely related. I'm not sure if you're aware of the bison or mallard evidence. American and European bison look the same (same species?) but European bison mtDNA is closely related to that of cattle rather than that of American bison. And northern hemisphere mallards also divide into separate American and Eurasian mtDNA. Eastern Eurasian mallards often have mtDNA closely related to that of Chinese spotbills, regarded as a separate species.
I'll find you the papers if you're don't already have them.
Terryt:
I have heard about the differences in mtDNA between Ameican bison and European ones. I didn't know about the differences between North American mallards and Eurasian ones, Frankly, I'm not entirely sure abut what any of this means(if anything at all). But it's also interesting that American bison have been mated with domestic cattle(whose breeds are themselves mixtures of several wild types or populations from different regions that have distinct genetic codes). And I think these "beefalo" are fertile, though I'm not 100% certain of this. As for mallards --- well, some form of mallard was the ancestor of domestic ducks, and there is a certain lake in Seattle where you can see ducks that are obviously hybrids between wild mallards and domestic ducks. So whatever the DNA differences between North American and Eurasian mallards, the ducks don't seem to care very much. Evolution is a pretty complicated, messy business in any case. BTW, I haven't read those papers. I don't even have them.
Anne G
Terryt:
BTW, who is Mathilda? I've read the Dienekes post on this, but I'd like to read hers, too, if you can give me the URL.
Anne G
Mathilda's anthropology blog:
http://mathildasanthropologyblog.wordpress.com/
Just lately she's put up a lot about genetics but I think she's mainly interested in ancient egypt. I'm sure you'll be able to spend quite a while looking back over her posts.
Yes. Beefalo are fertile. My brother's brother in law breeds them although I'm not sure why. They're not specifically bred for NZ conditions.
Mallards are considered to be a different species to spotbills although closely related. The fact they share mtDNA indicates this is not an accurate method of distinguishing species and yet the fact Neanderthal mtDNA is different from modern human is taken as proof they are separate species. Can't have it both ways, I say. Mallards readily hybridise with our local wild ducks as well as tame ducks. In fact the local wild ducks are virtually extinct in most parts of NZ. They've been bred out though, not replaced. Similar to Neanderthal/modern human interaction?
I'll fire the papers off to you via your private email.
Terry:
Thannks for the offer of the papers. I'll be happy to read them. I never heard of spotbill ducks before you mentioned them, but the fact that they and mallards share mtDNA is interesting, to say the least. And, because I'm kind of "into" wolves, had nave been for a long time, I've discovered over the course of my investigations, that all members of the genus Canis(wolves, coyotes, domestic dogs, jackals) are "interfertile"(in biological parlance, that just means they can interbreed and produce fertile offspring). And in certain parts of the US, that is exactly what wolves x coyotes have done. The "wolves" on Isle Royale, Michigan, all have mtDNA sequences that are normally found in coyotes. But they are all considered separate species. As I've said earlier, evolultion is complicated and messy, and whether or not Neandertals and "moderns" are two species or one big one, more and more evidence seems to be rolling in, that they shared genes at some point. This suggests to me that evolutionarily, they were/are more like wolves x coyotes(and other canids) or the gulls of Puget Sound, or the ducks you mentioned, than like certain similar but "specialist" species that you often find in such places as, say, the Amazon rain forest. BTW, I've added Mathilda's blog to my blogroll. It looks very good.
Anne G
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