Homo (sapiens?) neanderthalensis

Some weeks back it was announced – in the words of Jennifer Viegas of Discovery News, to take an example at random – that “All Non-Africans Part Neanderthal, Genetics Confirm.” The “confirms” part referring to the ongoing discussion about whether or not humans and Neanderthals bred with each other. Before now it was merely “thought,” now it is “confirmed.”

Naturally, this being evolutionary related, the Institute for Creation Research wants to get it’s opinion on the matter out there. The YEC point of view on Neanderthals is that they didn’t just breed with humans, they were humans, same as any other. And so, Brian Thomas has written a piece entitled More Evidence Neandertals Were Human. There is some confusion over the spelling used – I use an ‘h’ for Neanderthals, agreeing with Firefox’s spellchecker, Brian Thomas obviously does not, giving Neandertal.

The title of this post – Homo (sapiens?) neanderthalensis – is a reference to a concurrent debate on the classification of the group. The question is whether the Neanderthals are a subspecies of Homo sapiens, making them Homo sapiens neanderthalensis, or a species in their own right, which would be simply Homo neanderthalensis. This is complicated by the arbitrary nature of the definition of ‘species’. Generally it is considered that organisms separated by species lines should, by definition, not be able to interbreed – making Neanderthals a subspecies within our own – but in reality it’s not so simple. This is compounded by the difficulty of defining species temporally – where does a given species stop and it’s immediate ancestor begin? The tree of life is a messy thing.

What is Brian Thomas’ argument? He begins by claiming that “Evolutionists once ardently taught that Neandertals were links in human evolution,” in the hope of scoring a point on the basis that science was wrong. For starters, this doesn’t matter – as I said when talking about the recent reclassification of Archaeopteryx, “most fossils we find are the aunts of existing animals, not the direct ancestor” (although it should be pointed out that when it comes to more recent fossils we can indeed find direct ancestors, but we didn’t here on our first try) – and even if it did, science marches on. He goes on to make the claim:

Many of the DNA differences between that genome and modern man’s consensus genome were likely due to the Neandertal DNA having undergone base substitution “mutations” after burial.

But wouldn’t that be random? Or, in other words, why would the genomes agree with themselves? The original, 2010 study that did the actual sequencing sequenced not one but three individuals. I’m going to go out on a limb here and claim that there were fewer differences between the three than with modern humans.

The latest study, published in the journal Molecular Biology and Evolution, reconfirmed that Neandertals were fully human. The investigators compared a uniquely coded segment that they found on many X chromosomes common to non-African modern people to the recently published Neandertal X chromosome sequence. They found that Neandertals had the segment, too. The study authors wrote that Neandertals and modern humans experienced “very early admixture.”

You might notice that Mr Thomas is trying to imply that only non-Africans were tested. In reality, it was found that Africans don’t have the segment. This is arguably an evolutionary prediction – Neanderthals lived in the places that humans leaving Africa would have had to pass through, but had no such direct contact with Africa itself. If something different was found from what was, then we would be in a different situation. This fact really demolishes Mr Thomas’ thesis – he really has a habit of forgetting to mention inconvenient facts like that. He finishes with a biblical quote, which I shall ignore.

On a related note I should point out that it was once thought that Neanderthals were hunched over, until it was discovered that the specimen they were looking at had a spine injury. Nevertheless, it cannot be claimed that there are no differences between ‘modern’ humans and Neanderthals – for example they were more robustly built and had much larger brains. Indeed, I would argue that at present the idea that breeding with other humans is looking like the best explanation for what “killed off” these supermen.