Speaking about a Controversy, Part 2 of 2

Speaking about a Controversy, Part 2 of 2

Does the Presence of a “Speech” Gene Mean Neanderthals Had Language?  An article recently published in Current Biology has generated a lot of excitement about the possibility of Neanderthal language capacity. Scientists from the Max Planck Institute at Leipzig, Germany, announced the isolation of the so-called language gene from a Neanderthal specimen recently recovered in Spain. Some anthropologists interpret this discovery as evidence that Neanderthals had language. What does this mean for RTB’s biblically based human origins model?

Last week I provided some background information needed to understand the work of the Max Planck scientists. This week I will detail their findings and discuss the implications of their research for the RTB human origins model.

Controversy surrounds the question of whether or not Neanderthals possessed language capacity. Anatomical studies remain ambiguous. (See Who Was Adam? for a detailed discussion.) To help resolve this debate the team from the Max Planck Institute turned to ancient DNA analysis to probe for the language gene in the Neanderthal genome.

In 2001, a research team from the United Kingdom reported that mutations in the FOXP2 gene cause severe language disorders. Presumably the FOXP2 protein plays a key role in controlling the development of brain and facial structures that support aspects of human language capacity.

An initial evolutionary analysis of the FOXP2 gene, conducted in 2002, indicated that the human variant arose about 200,000 years ago. Subsequent work published later that year placed the origin of the human FOXP2 gene at about 100,000 years ago. From an evolutionary standpoint, this is well after the time that humans and Neanderthals allegedly split from a common ancestor. Accordingly, Neanderthals should not possess a human-like FOXP2 gene and, therefore, language ability.

To everyone’s surprise, the team from the Max Plank Institute isolated the human variant of the FOXP2 gene from a recently recovered Neanderthal specimen. Some have interpreted this result as evidence that Neanderthals had language. If so, what does this mean for the RTB human origins model which predicts that Neanderthals and other hominids should behave in non-human ways?

Did Neanderthals possess language ability? This conclusion is premature for a number of reasons.

First, the very real possibility exists that this result stems from contamination by human DNA. Clearly, the research team went to painstaking efforts to avoid contamination. Anthropologists suited up in clean room gowns and face masks and used sterilized tools to excavate the Neanderthal remains. They designed the extraction protocol to avoid isolating any human DNA and ran the appropriate controls to ensure the Neanderthal DNA samples had no human contamination. In spite of these heroic efforts, the possibility of contamination cannot be ruled out. The Max Planck researchers previously introduced contamination into a Neanderthal genome sample they were working with and wrongly interpreted this as evidence for human-Neanderthal interbreeding.

Even if these results are taken at face value, it still doesn’t mean that Neanderthals possessed language. As discussed last week, the presence of the FOXP2 gene is necessary for language in humans, but not sufficient. Myriad other genes must be present and properly expressed to give humans the ability to speak. To date, these other genes have not been identified in humans, let alone Neanderthals.

It is also conceivable that the Neanderthal FOXP2 gene is distinct from the human variant. The researchers did not isolate the entire FOXP2 gene. Instead they isolated the portion of the gene where the distinguishing features of the human variant reside. It could well be that when the entire gene is sequenced other regions it will display unique Neanderthal signatures.

Another troubling aspect of this study is that its results run contrary to other studies. For example, if Neanderthals had the human version of the FOXP2 gene, then from an evolutionary perspective the origin of the gene must have taken place prior to the time that Neanderthals and humans shared a common ancestor, which would be at least 500,000 to 750,000 years ago. Yet, as mentioned last week, evolutionary analyses place the origin of the human variant between 100,000 and 200,000 years ago. Additionally, the archeological evidence and brain-structure studies don’t support the existence of Neanderthal language. (See Who Was Adam? for details. Also, see a past TNRTB entry about Neanderthal division of labor.)

Did Neanderthals have language ability? In spite of the discovery of the so-called language gene in Neanderthals, the question still remains unresolved.

Still, the work by the scientists from the Max Planck Institute demonstrates the power and potential of ancient DNA studies to help us move toward resolving important scientific controversies.

Part 1 | Part 2