100,000 - 50,000 years ago, there were at least 4 separate subspecies of humans: us, Neanderthals, Denisovans, and some other group(s) dispersed into Asia.
They did interbreed, and relicts of their DNA are still found in our DNA today. What is not clear are how many, as this is ongoing genetic archaeology at the moment.
The percentage DNA has been pretty much concluded. Up to 4% Neanderthal in Caucasians, close to zero in Africans. Just 0.2% Denisovan in Asians, but this is significantly higher in Melanesians and indigenous Australians.
I donāt think there is enough extractable DNA available from the other group(s).
There are at least three proposed subspecies of homo sapiens referred to in academic literature: Homo Sapiens Neanderthals, Homo Sapiens Fossilis, and us: Homo Sapiens Sapiens. The previous two are extinct, and no academic literature argues anything other than the existence of one subspecies of human today. Unless you happen to have a link to a paper published in a trusted peer reviewed scientific journal that suggests otherwise? If no then the suggestion of the existence of human subspecies is not āscientificā because it has no basis in the scientific literature.
Conversation with wild suggestions about āscienceā that have no basis in the scientific literature is not what I would think of as āunbiased mature conversationā. My suggestion that human can fly - I saw it in a superman movie - are just as valid as the suggestion that there are multiple human subspecies. (i.e. not valid at all)
We categorize peoples into groups by cultural, historical, geometrical, administrative etc. characters. Is it a taboo to do so by biological characters?
Not necessarily taboo, but it is not āscienceā and it is not scientific ābiology.ā If it was it would be represented in the peer reviewed literature. So yea, talk about it but donāt pretend that it is something that it is not. (not saying that you did that of course)
I dont think you are realizing what i wrote above. Perhaps go up and referrence.
Basically it is about the taboo on studying this kind of thing amongst the majority and that has influence on scientific study. I am not saying there are or arent many subspecies of modern day humans. What i am saying saying is the rank of subspecies is more well defined and accurate and humans have a lot of variation which is obvious and consistent within certain groups (especially geographical).
As with the medicine point, there are valid reasons to accept this fact and study it. I dont study humans so not going to tey and make it a thing. But have been breeding and hybridizing animals and plants for 20 years and going out on field studies to study wild populations. So am a little bit familiar with characters, reproductive possibilities and line breeding etc. Its very clear humans have incredibly unique and diatinguising features that in any other case would classify them into sub species or varieties. The thing with subspecies is that its slightly more well defined and āconcreteā than say race or any of the even lower ranks in plants.
See the link to a psychology article posted above talking about this very point of not studying sensitive topics. Yes we are aware there are a few that do. Also aware there are many who avoid it.
For those reading and not getting the context of this thread it started here talking about chinese claiming english and evolution of languages etc.
Iām not certain how this fits in with the conversation but people who have a preponderance of genes from a particular racial group are sometimes more likely to develop certain diseases, socioeconomic factors notwithstanding. More people with African ancestry, for example, tend to develop type 2 diabetes.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4540762/
Itās all very complicated, though. And it definitely doesnāt make us different species.
That is incorrect. There is no accepted standard for determining what a āsubspeciesā is.
https://conbio.onlinelibrary.wiley.com/doi/abs/10.1111/j.1523-1739.2006.00530.x
If there is a species that shows variations in a similar way with human, how do biologists categorize them? And do human try to somehow keep uniqueness of each population or do we let them mix naturally?
The Siberian Tit thinks itās racist, though
The tits and chickadees are a taxonomic family, so that includes quite a few different genera not to mention different species. The corresponding level of taxaonmy for humans would see us listed alongside the great apes
is that kind of study avoided?
Itās amazing how our knowledge of human ancestry is continually being updated.
Itās fascinating and very complex.
Youve got waves of migration, extinction, divergence and hybridisation, happening over 100s of thousands of years. Out of Africa was hopelessly simplistic even if mostly right.
The last part needs to be qualified as Denisovans were unknown to science until about ten years ago, so we didnāt really go looking for Denisovan DNA until very recently. Thereās a possibility thereās some other human species that we missed in our ancestry.
As for what makes a species a species, well mating with a member of another species is supposed to have the usual result of an infertile hybrid.
Subspeciesā¦Thereās no good definition Iām aware of.
people claiming āthe scientific literature states thatā¦ā need to be very mindful of the fact that the whole field of paleogenetics is only 10 years old, since Svante Paabo essentially invented the field in 2007 by developing the first techniques that could even detect old DNA in 100,000 year old bones, let alone be accurate about it. The first papers showing Neanderthal DNA in our genome are less than 10 years old. Denisovans, only 7 years old, and the most tantalising glimpses of yet further undiscovered groups are even younger revelations.
but being able to find a 90,000 year old finger bone of a young girl in a cave in Russia and have indisputable evidence that her father was a Denisovan her mother a Neanderthal, well, that paper is only a year old.
[DOI: 10.1038/s41586-018-0455-x Nature 2018](https://www.nature.com/articles/s41586-018-0455-x)
So just be careful of relying on the literature, unless youāre really up to date, and throw out most of what you read that was written before 2010, because they really did not know what we know now.
because like how different looking humans can breed, so can gorillas, oranutangs, chimps and bonobos get it on and raise children with one another?
@geajvopās post says the differences of tits in @IbisWtfās post is equivalent with the differences of those apes.
Is this closer?
Nope, those tits on that page are all Poecile genus, so as close as us to, well, no one else (as we are the only extant Homo species). Some chickadees are also in genus Poecile.
Now, if we were comparing tits to great tits and to titmouses, blue tits, and so on, we would have to draw a wider net and call them Paridae (which as a Family is still a closer grouping than all great apes). Orangutans are excluded from the Hominidae family, but are in the larger Hominoidea superfamily.
confusing.
some families have really distant genera lumped in together for convenience still, while other families have seen so much adaptive radiation and local speciation that there are thousands of species in one genus (like with Eucalyptus, or Acacia). further complicated by hybridisation, especially between races. Which are artificial distinctions to be sure, but nonetheless very convenient for grouping localised instances of gene clustering limited by biogeographical constraints. and thatās the point of this whole discussion, no?
can Homo and Pongo species interbreed? not sure what the take of the makers of Planet of the Apes would be on that, but youāre welcome to try and report back to us.
I think that chimps and bonobos can interbreed, but donāt normally do so. I am interested to hear from someone who knows one way or the other.
I for one would be happy to be classed as a different species to the OP 
we are talking on human kinds. Not on the bear.