I was just thinking about this, and wanted to ask
In: Biology
Wolves and dogs share 99.9% DNA, does that make a dog a wolf?
The line that makes different species isn’t a hard set thing, it’s actually a wider grey area because sometimes it’s difficult to define if two species are truly different because they are so similar.
The general rule seems to be, if they are unable to interbreed successfully then they are separate species. Some dogs can’t make offspring with wolves, but others can. So what does that mean?
So we classified Dogs as a subspecies of Wolf because they are very similar but still clearly different.
It’s believed that Neanderthal and Humans interbred but all male children were sterile like Mules. The evidence for this is that all of our Neanderthal DNA is in the X chromosome.
So originally there were human + Neanderthal hybrids, but over time they bred with humans to the point were the Neanderthal DNA is barely noticeable. Red Hair is believed to have come from our Neanderthal genes for example.
So Neanderthal is extinct because they are no living examples. We just happen to have a small amount of their DNA.
But Europeans that have said DNA are extremely similar to Africans that don’t, and we can interbreed without issue, so we aren’t considered different species.
Most of us have some† DNA identical to a banana’s DNA. I don’t think that makes us a banana. Neanderthals went extinct when there were no more of them around. Modern humans evolved from them, over many generations, but that’s not the same as being them.
† Edit: Clearly, having all our DNA identical to a banana would make us a banana. Sorry if that was unclear.
Modern Humans (capital H) are only one of several species of humans (lowercase h) that existed in the past, the same way that there are different kinds of tigers and dolphins and owls, etc.
For various reasons, we are the only kind of humans who survived to the modern day, but there were tens of thousands of years when Humans existed with or near other humans in various places around the world.
Neanderthals were a kind of human that mostly lived in the warmer parts of Europe and western Asia. Denisovans were another kind of human that lived in Asia (we don’t have as much information on specifically where other than what is now Siberia).
Humans mostly stayed in Africa for a long time, but at one point a lot of Humans spread out to these areas where the other humans had been living.
We probably weren’t always friendly, but at least on a few occasions the Humans who moved out of Africa had babies with Neanderthals and Denisovans (and probably other species of humans!) who grew up and had babies with other Humans, and some of the DNA from those other humans eventually found its way into pretty much all of the Humans in those parts of the world today.
The line between *Homo sapiens* and *Homo neanderthalensis* gets murky when you consider that they *did* successfully interbreed violating the traditional definition of a species, and similarly making it hard to determine whether either species is still alive today.
However, 1-2% of DNA from humans of European and Asian descent, and close to 0% of Africans, originates from Neanderthals. Take from that as you will.
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