In 1856 workers for a limestone quarry in Neanderthal (Neander's Valley) in Germany uncovered some unusual bones in the rubble of a cave. The cave mouth had been blasted to give better access to the limestone of the cave. The bones were human-like but differed enough from humans that some speculated that they were from a cave-bear rather than a human. The bones were thicker than humans and the brow-ridges were also thicker and pronounced. The bones were given to a local school teacher and amateur scientist who recognized their significance. They seemed be from a member of race that was distinctly different from humans. The problem that scientists wrestled with for decades was: What was the relationship between the creatures who came to be known as Neanderthals and modern humans? There was then and continues to be to this day people, including scientists, that deny that the Neanderthal bones represent any beings different from humans. These skeptics maintain that the bones found represent humans suffering from some deformity. In the years immediately after the discovery the favorite explanation for the characteristics of the Neanderthal bones is that they were the result of rickets, a childhood disease resulting from insufficient vitamin D. This contention was dropped when other skeletons were found with the same characteristics, including what appeared to be family groups. But the human deformity explanation of the Neanderthals resurfaces from time to time in different forms. The latest version of this contention is that the Neanderthals were simply humans who suffered from iodine deficiency. The human thyroid gland requires iodine and if it is not available there are abnormalities in human development. This line of argument has not convinced many but the interesting thing is that there are still people almost a century and half after the discovery of the Neanderthal bones that refuse to accept their distinctness from humans.

But the acceptance of the Neanderthals as a distinct group did not end the controversy. The next question was whether they were ancestors of humans, particularly Europeans. The first discoveries of Neanderthals took place in Europe but that could be simply because there was more archeological digging going on there in the nineteenth century. Later Neanderthal skeletons were found in the Middle East, as far east as Iran. But outside of the Europe that was south of the glaciers of the Ice Ages and the Middle East there have been practically no discoveries of Neanderthal remains.

In the mid 1990's researchers were able replicate enough mitochondrial DNA from some the first Neanderthal bones found to carry out a a comparison with modern human mitochondrial DNA. The results indicated that Neanderthals were enough different to constitute a different species from modern humans. The statistical results given in a Science article of July 1997 were that there were differences in the Neanderthal and modern human DNA at about 25 positions. Chimpanzee mitochondrial DNA differed from that of humans at 55 positions. There is some variation in this DNA among modern humans but only on the order of 8 positions. So the conclusion was that Neanderthals represented another species closer to humans than chimpanzees but still distinct.