As mentioned in a previous post, the question of whether or not Neanderthalers were able to have offspring continues to be hotly debated by scientists. Depending on the answer given, we would have to classify Neanderthalers either as people like us, or people very different from us. Of course, proponents of both of these statements claim they have evidence to back up their very different positions.
Those who suggest that there was interbreeding between our ancestors (Homo sapiens sapiens) and Neanderthalers would label Neanderthal bones as belonging to Homo sapiens neanderthalensis.
With this label, the word “Neanderthalensis” appears in the third position of the nomenclature, which refers to the level of sub-species. This implies that the differences between us and Neanderthalers are so small that they are contained within the range of variation one would expect to find within a species (in other words, we are related to Neanderthals on a sub-species level, rather than being classified as two different species.)
According to this interpretation, the ability to interbreed with modern humans might have also spelled doom for the Neanderthals. But if the two species interbred, why don’t we see the “typical Neanderthal look” today?
As time went by and interbreeding between our ancestors and Neanderthalers continued, the thinking goes that the Neanderthalers’ genetic contribution to each new generation became ever smaller. Eventually, this percentage became so small that all people began to look like humans rather than a Neanderthal individual.
Scientists refer to this scenario as genetic swamping. If this is what happened, it would be possible for the two species to have interbred over many generations, while also explaining why the influence of Neanderthaler genes can’t be seen by the naked eye. A child burial uncovered in Portugal is seen as evidence that “admixture between the two groups must have been significant, at least in such cul-de-sacs as the Iberian Peninsula,” providing more support for this position.
Here the term “neanderthalensis” is in the second position of the nomenclature, referring to the species. This is a scientist’s way to say that the difference between humans and Neanderthalers is at the much more significant species level. This has an important implication: according to these proponents, Neanderthal populations and Homo sapiens populations could not have produced fertile offspring.
Of the two positions just outlined, most scientists prefer the second one and refer to DNA analysis for support. DNA analysis of Neanderthal bones has been undertaken for a while. A comparison of Neanderthal DNA against modern human DNA suggests that there are enough genetic differences to warrant labeling them as a separate species.
Most scientists, therefore, prefer seeing “Homo neanderthalensis” in the scientific literature. Since interbreeding and subsequent genetic swamping cannot occur in this scenario, the disappearance of the Neanderthalers is blamed on outright genocide practiced by our ancestors, or greater hunting skills on the part of the newcomers.