What's it feel like to be wrong about something for over a decade? The neanderthal is a very advanced, extinct ape. His DNA was halfway between ours and that of a chimpanzee, and we are totally unrelated to him other than possibly for similar design elements.
In fact, all vertebrate animals share pretty much the same base of skeletal parts, internal organs, chemistry, etc. Essentially the same genes make the same things, species by species.
We are much more than brothers to the other species that share this world with us.
Now, when you get to epigenetics, or the control features exterior to the main DNA strands, you run into VAST differences.
That's where you will find the stuff that makes us human. It also makes cows cows, and pigs pigs.
We only recently discovered epigenetics and really have little idea how it works.