Pre-Historic Nookie!

[The Grand Nudger]

Species can be difficult to pin down (not as difficult as some might imply) - but this isn't a particularly good example of that.

Because the mule example has been brought up...I'll elaborate by reference.  A certain percentage of our dna is neanderthal in origin.  If this relationship were similar to mules..then we would expect that modern horses had a similar percentage of donkey dna.  They don't.  Their shared genetics comes at the level of genus.

The reason that they don't is obvious, and it's related to why horses and donkeys aren't the same species (or subspecies of the same species).  Their offspring are overwhelmingly sterile.  They are not breeds of horses or donkeys but an entirely different animal.  Chromosomal incompatibility forces this.

We couldn't have a noticeable amount of neanderthal dna, today, if the outcome of our mating with them was similar to the outcome of a horse and a donkey mating.  Not only do we have neanderthal dna in modern human populations, we have denisovan dna in modern human populations. Combine this with a denisovan/neanderthal breed....and this strongly suggests that the relationship between the three is one of concurrent subspecies..rather than distinct species with both freak interbreeding instances..and even more freak -fertile- offspring and subsequent interbreeding between all three of those freak fertile interbreeding instances...all amounting to an unrepresentative showing of dna in modern populations.

Could it happen? Maybe....the odds are beyond long, and there's a much simpler and much more probable explanation which fits available data in every way that the long odd hypothesis doesn't...and all of this is explained by the genus, species, subsp, breed model, rather than being muddied up by it, just as modern variations within subspecies are.

The confusion, such as it is, goes back to a quick generalization we all learned in school as a shortcut for a complex picture. That if two animals -can't- breed with each other, they aren't the same species. This is true. However, it doesn't actually follow from that that there are no two species which can, but our mind makes this connection and creatards latch onto it. Combine this with the fact that popularizing articles often say "two different species" rather than "two different subspecies" and the knot is well and truly tied.

[Gawdzilla Sama]

 Born of an ass climbing up a maer. Shit, that would require some leverage.

The mare is quite ready, and cooperates. The donkey is hung like a ...

[LadyForCamus]

Huggy will be here in 3...2...

[Angrboda]

https://www.rawstory.com/2018/08/saga-ea...ies-child/



Somehow the inerrant bible missed this chapter!

The crapinists will argue, "But I thought you said separate species cant mate"?

Um no, that is not what evolution says. As long as the genes are close enough in DNA they can, but once the shuffling creates too much difference the species will not be able to mate.

Morons will claim we are advocating fucking monkeys, but no. It is no different than knowing that humans cross breed plants all the time and create new species.

You cannot today, fuck a baboon as a human and make a baby, because our genes are too far removed. But in this case in your story the separate but still homo line was still close enough at that point.

Evolution is as simple as knowing that grass and trees while not the same species, are closer related than they are to humans. Just like domestic house cats and big cats like tigers and lions are still called cats.

The definition of species is in fact reproductive isolation. That Neanderthal and Denisova produced a hybrid is a result of the dependence on morphology for classifying species. But morphology is not how species is defined, so technically they would be right.

[Anomalocaris]

Species can be difficult to pin down (not as difficult as some might imply) - but this isn't a particularly good example of that.

Because the mule example has been brought up...I'll elaborate by reference.  A certain percentage of our dna is neanderthal in origin.  If this relationship were similar to mules..then we would expect that modern horses had a similar percentage of donkey dna.  They don't.  Their shared genetics comes at the level of genus.

The reason that they don't is obvious, and it's related to why horses and donkeys aren't the same species (or subspecies of the same species).  Their offspring are overwhelmingly sterile.  They are not breeds of horses or donkeys but an entirely different animal.  Chromosomal incompatibility forces this.

We couldn't have a noticeable amount of neanderthal dna, today, if the outcome of our mating with them was similar to the outcome of a horse and a donkey mating.  Not only do we have neanderthal dna in modern human populations, we have denisovan dna in modern human populations. Combine this with a denisovan/neanderthal breed....and this strongly suggests that the relationship between the three is one of concurrent subspecies..rather than distinct species with both freak interbreeding instances..and even more freak -fertile- offspring and subsequent interbreeding between all three of those freak fertile interbreeding instances...all amounting to an unrepresentative showing of dna in modern populations.

Could it happen?  Maybe....the odds are beyond long, and there's a much simpler and much more probable explanation which fits available data in every way that the long odd hypothesis doesn't...and all of this is explained by the genus, species, subsp, breed model, rather than being muddied up by it, just as modern variations within subspecies are.

The confusion, such as it is, goes back to a quick generalization we all learned in school as a shortcut for a complex picture.  That if two animals -can't- breed with each other, they aren't the same species.  This is true.  However, it doesn't actually follow from that that there are no two species which can, but our mind makes this connection and creatards latch onto it.  Combine this with the fact that popularizing articles often say "two different species" rather than "two different subspecies" and the knot is well and truly tied.

If the genetic contribution of Neanderthals and denisovans to HSS were highly advantageous to HSS ancestors, there need not be any substantial number of successful interbreeding between HSS and other populations for the genetic contribution from those other populations to be highly selected for, and thus prevalent amongst modern HSS gene pool.

The fact that all humans outside Africa today carry a significant Neanderthal genetic contribution only says successful interbreeding occurred at least once. It diesn’t Say interbreeding was frequent or trouble free. So it diesn’t Say Neanderthal and HSS are necessarily close enough to have no barriers to interbreeding that would have made them difference species.

[The Grand Nudger]

So it diesn’t Say Neanderthal and HSS are necessarily close enough to have no barriers to interbreeding that would have made them difference species.

I think you may be off on the amount of interbreeding it would take. If it only happened once, that would suggest that every living human being (with that marker) has that couples fertile progeny somewhere in their ancestry - both that and their progeny being fertile are unlikely..if they were different species- and we're talking about an interaction between three populations, here.

Regardless there's a misperception regarding subspecies and breeds.  Different subspecies within a species can and do have barriers to regular interbreeding.  Just as different breeds within a subspecies do.  This is -why- the notion that we're dealing with three subspecies fits the data better than the idea that there were three distinct species capable of interbreeding with each other -and then passing on that dna-.

Those barriers don't make them different species, though they commonly make them different subspecies, breeds, etc. As jorg mentioned, isolation is probably the best way to address species. Ill try to find it, but there was a great definition I read once, something about a species being the most inclusive reproductive grouping between hypothetically campatible populations.

[Anomalocaris]

The Neanderthal and denisovan genes are not present in sub-Saharan African HSS. So that eliminates the problem of the result of interbreeding has to be the ancestor of all HSS. The bar for a single individual in euroasia being the shared common ancestor of all euroasia HSS is much lower because the founding population of almost all euroasia HSS is recognized to be fairly small and relatively recent.

[Minimalist]

Huggy will be here in 3...2...

And I bet he brings a fucking bible verse with him.  Those assholes never get too far from their bullshit bible verses.

[GUBU]

They're all homo sapiens sapiens.  We're a subspecies.  The Doubly Wise, a misnomer if ever there were one, lol.  Current data suggests that homo sapiens neanderthalenthis and denosova were also a subspecies.

(there are, ofc, taxonomic classifications under subspecies as well..and these account for difference within the sbsp - as time goes on...lol..well need to start adding extra rungs to the bottom of the ladder)

I much prefer the alternative classification thought up for us by Pratchett, Stewart and Cohen Pan narrans, the storytelling ape.

[The Grand Nudger]

The Neanderthal and denisovan genes are not present in sub-Saharan African HSS.  So that eliminates the problem of the result of interbreeding has to be the ancestor of all HSS.   The bar for a single individual in euroasia being the shared common ancestor of all euroasia HSS is much lower because the founding population of almost all euroasia HSS is recognized to be fairly small and relatively recent.

As I said, I'm not saying it's impossible..only that a single paring leading to fertile offspring between three distinct species is far less probable than infrequent breeding between distinct subspecies.  

We're weighing, in effect, two very rare occurrences happening together, and thrice - inter species pairings producing offspring, and viable offspring....against a routine occurrence -intra species pairings producing viable offspring.