Over in the Cafe Society, I was looking at this thread, in which a poster mentioned the absurdity of the sci-fi idea that alien beings could actually interbreed with human beings (producing half-klingon / half-human amalgams for example), likening the half-human/half-alien to crossing a blue whale with a fern.
But then the thought occurred to me - assuming that the Neanderthal man had not died out, would Cro-Magnon / Homo Sapiens / we be able to interbreed with them, or would our two species be two biologically dissimilar to create mixed progeny? Is there any anthropological evidence to support whether they in fact DID interbreed?
I realize it’s a moot, rather silly question, but it’s one of those cases where, once I thought of it, I couldn’t get the notion out of my head.
I don’t know the answer to your question, but something you might want to consider is that there’s still silly arguments abound about chimps and humans interbreeding. It’s been asked before and the consensus was that, it’s impossible, but no, we don’t have a cite of anybody who tried and failed in a scientific manner.
Not a silly question at all, and one that has been hotly debated in the scientific community.
Some anthropologists have supported the proposition that Neanderthals interbred with early modern humans in Europe, and even trace some European traits to that interbreeding. However, genetic evidence has made it increasingly probably that all extant humans are descended from populations that emigrated from Africa, and did not interbreed with local populations of earlier types of humans.
Mitochondrial (non-nuclear) DNA has been extracted from Neanderthal bones, and has been found to be very distinct from that of modern humans. It is on this basis that an increasing consensus has developed that Neaderthals be regarded as a full species relative to Homo sapiens, rather than a subspecies. However, there is still some dispute about this, and it is possible that analysis of nuclear DNA could tell a different story.
The issue of interbreeding between humans, Klingons, or other aliens is completely different. Aliens would not share any common ancestry with humans (whereas Neaderthals would have had fairly recent common ancestry. Having developed separately, the genetic code of aliens would be completely different, making it impossible for interbreeding to take place. It would be like shuffling together the pages of two novels written in English and Chinese and expecting it to make sense.
Actually, the consensus was that, although unlikely, it would not necessarily be impossible. However, it would take experiments to find out.
It is quite possible that modern humans and Neaderthals would have been able to produce hybrids, either sterile or perhaps even fertile. However, the evidence suggests that if interbreeding did occur, it was not widespread enough to leave a trace in modern populations.
It’s not a moot question at all. It was (and to some degree, still is), in fact, a widely-held, if not accepted, theory in anthropological circles that interbreeding with humans was at least partially responsible for the disappearance of Neanderthal man. It has been demostrated through DNA research that it was, at least, biologically possible. There is some evidence to support this, but there is also evidence against it. See here and here.
This could also indicate that the majority of sapiens/neanderthal crossings were a male neanderthal and a female sapiens. If this were the case, then one might find a significant number of neanderthal genes in the nuclear DNA, but little to none in the mitochondrial.
Or, those mitochondrial lines simply died out. If there weren’t that many, it is very conceivable that the lines just ended some time in the past. The Neanderthal/Sapiens split appears to have happened about .5M years ago. That just seems way too recent for interbreeding to be impossible. Our closest relatives, chimps and bonobos, diverged about 2M years ago, and they are inter-fertile. While the evidence available tilts toward no interbreeding of Sapiens and Neanderthal, that evidence is pretty thin.
As for Klingon/Human type hybrids, I do believe that in one ST episode (Enterprise, IIRC) it was explained that considerable tinkering had to be done to produce the inter-species hybrids. IOW, it wasn’t simply mating.
The main objections being that, 1) The skeleton dates from a period 4,000 years or more after Neandertals are thought to have become extinct in the area; and 2) the skull has Cro-Magnon features, while the body resembles Neandertals. One would expect that a true hybrid would be intermediate in both, rather than favoring one ancestor in the skull and the other in the body.
Keep in mind that the term “hybrid” is being used losely here. Zihao is not claiming that one parent was Neanderthal and the other Sapiens. He is saying that the child’s skeleton shows evidence of interbreeding in the past. Also, the skull does have some Neanderthal like features and some of the lower body had Sapiens like features.-- it’s not like it was a Sapiens head on a Neanderthal body. That, of course, would be ludicrous. It would also had helped if the skeleton had been an adult, and not a young child. As I’m sure you know, the morphological differences are more evident in adults.
BTW, I’m not saying I agree with Zihao and Trinkaus on this, just pointing out that the data is a bit more ambiguous than you imply.
This can get a bit circular. According to the Biological Species Concept, species consist of populations that are actually or potentially reproductively isolated from other populations. It can be a judgement call as to exactly how much interbreeding has to go on before two populations must be considered as subspecies within the same species, vs two separate species. There are often disputes among taxonomists about which populations should be considered subspecies, and which full species.
We don’t actually know for sure what the situation was between Neandertals and early modern humans. Some geneticists estimate that about 2 million years of isolation is generally required for full speciation; since modern humans and Neandertals had been separate for only 500,000 years, this suggests that interbreeding was likely to have been possible. On the other hand, the genetic evidence indicates that if interbreeding did occur, it was not very common or widespread. There well could have been behaviorial differences that prevented interbreeding (such as both groups thinking the other was uglier than sin). By this criterion, the two populations would have qualified as species according the the Biological Species Concept. When scientists say that Neandertals and modern humans constituted different species, it is this kind of criterion they are thinking of.
Lumpers and splitters. In my younger days, I was much more of a lumper. As I get older, I find myself being more of a splitter…
Personally, I think the 2 species distiction makes sense given that we know there was at least 10,000 years when the geographic ranges of Neanderthals and Sapiens overlapped, and yet there is so little evidence of interbreeding. You’d think that if interbreeding were common, we’d find evidence all over the place. (Of course scientists like Milford Wolpoff thinks he does see evidence all over the place.) Still, I’m a splitter.
That’s not really a reasonable conclusion. We know of a great many species that overlap geogpahically, are nearly perfectly interfertile, yet produce hybrids so rarely that they would have little chance of showing up in fossil records.
The other issue is whether a hybrid would look like a hydbrid, or whether we have the same situation we find with Przwalski and domestic horses. In these cases hybrids look like one or the other parental line and very rarely like a mixture of the two.
Paleoanthropologist Björn Kurtén wrote a novel, Dance of the Tiger, to illustrate this theory. Kurtén must have been a splitter, because this plot turns on species differentiation.
Neanderthals (called “Trolls,” because this is Scandinavia) find sapiens sexually irresistible because our facial features are infantilized relative to them. We share facial features with Neanderthal babies: high forehead, smaller jaw, no brow ridges. On the ethological basis across species of finding infantile features attractive (oo “baby”, I love you “baby”), the Neanderthals mated with so many sapiens, producing sterile interspecies offspring, that they died out. In other words, love, not war, eliminated the Neanderthals.
Not necessarily, since if two different forms were known to usually produce sterile hybrids then any taxonomist, whether lumper or splitter, would regard them as separate species. It’s only in the case where two forms are definitely known to be capable of producing fertile offspring (but do not do so regularly, or over wide areas), or where the result of possible mating is unknown, that the question of lumping or splitting would arise.
In any case, that’s an interesting proposition, but what do the Cro-Magnons think about mating with trolls?
In studies of two species of fruit flies which produce sterile hybrids, it was found that females had a strong tendency to mate with males of the same species, while males did not discriminate at all.
It has been many years since I read that book, but IIRC the first instance of interspecies mating is kind of a female Meanderthal more or less raping a Sapiens male. “Rape” may be a bit strong, but she was most derinitely the aggressor.
Kurten did a good job of playing against Neanderthal stereotypes-- they were fair skinned folk with a culture so polite that they always used honorifics when talking to each other. Sapiens, otoh, are Black-- being from the south. Not a bad book-- and Kurten is a actually well known paleontologist.