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Update: Still No Evolutionary Explanation for Human Language


Back in 2014 we reported, “Leading Evolutionary Scientists Admit We Have No Evolutionary Explanation of Human Language.” Despite excited claims to the contrary, it was clear that a “miracle mutation” to the gene FOXP2 was not responsible for the emergence of the uniquely human ability to use language.

But what about FOXP2 — a gene that seems to be connected to language, where humans have a couple of unique amino acid differences compared to nonhuman primates? In The Language of God, Francis Collins presented FOXP2 as something of a miracle mutation that could have caused human language to develop (see pp. 139-141). Time Magazine once claimed that our two amino acid differences in this gene could have caused “the emergence of all aspects of human speech, from a baby’s first words to a Robin Williams monologue.”

Sorry, we said, “we aren’t even sure exactly how FOXP2 affects language.” The Evolution News article cited research in the journal Frontiers in Psychology that poured cold water on the claims of Dr. Collins, Time Magazine, et al.

More Cold Water

It’s good to be right, as well as several years ahead of the curve. Now here’s the headline from yesterday in Nature, citing new research reported in the journal Cell, “Diverse genome study upends understanding of how language evolved.” Subhead: “Research casts doubt on the idea that the FOXP2 gene — linked to language evolution — is special to modern humans.”

Just as we said! From Nature:

The evolution of human language was once thought to have hinged on changes to a single gene that were so beneficial that they raced through ancient human populations. But an analysis now suggests that this gene, FOXP2, did not undergo changes in Homo sapiens’ recent history after all — and that previous findings might simply have been false signals.

“The situation’s a lot more complicated than the very clean story that has been making it into textbooks all this time,” says Elizabeth Atkinson, a population geneticist at the Broad Institute of Harvard and MIT in Cambridge, Massachusetts, and a co-author of the paper, which was published on 2 August in Cell1.

Originally discovered in a family who had a history of profound speech and language disorders, FOXP2 was the first gene found to be involved in language production2. Later research touted its importance to the evolution of human language.

A key 2002 paper found that humans carry two mutations to FOXP2 not found in any other primates3. When the researchers looked at genetic variation surrounding these mutations, they found the signature of a ‘selective sweep’ — in which a beneficial mutation quickly becomes common across a population. This change to FOXP2 seemed to have happened in the past 200,000 years, the team reported in Nature. The paper has been cited hundreds of times in the scientific literature.

Guess what? Despite all the citations, they were wrong.

[T]he signal that had looked like a selective sweep in the 2002 study was probably a statistical artefact caused by lumping Africans together with Eurasians and other populations. With more — and more varied — genomes to study, the team was able to look for a selective sweep in FOXP2, separately, in Africans and non-Africans — but found no evidence in either.

“It’s good that it is now clear there is actually no sweep signal at FOXP2,” says evolutionary geneticist Wolfgang Enard of Ludwig Maximilian University of Munich in Germany, who was a co-author of the 2002 study.

That is what I would call putting a really cheerful face on it. Your widely touted study was based on a “statistical artifact” and “It’s good that it is now clear.” 

A Vindication for Denton

As we put it in the 2016 video The Biology of the Baroque, summarizing some of Discovery Institute biologist Michael Denton’s work:

The case that human language develops step by step through natural selection is further weakened by the fact that no single language gene has ever been discovered. That is, the needed complexities seem to have arisen spontaneously in a self-organizing emergent fashion. Non-adaptive and beyond-adaptive order poses an existential challenge to Darwinism because it means there are huge parts of the history of life that not only can’t be explained by Darwinian evolution but they are completely outside the domain of natural selection.

In fact, the final five minutes or so (starting at 14:05) of the video are about as powerful a reminder as you can find of the challenge to Darwinism, much more fundamental than questions about FOXP2, from the human gift you are exercising right now as you read this. Do yourself a favor and watch the whole thing.

Photo credit: Screen shot from The Biology of the Baroque, courtesy of Discovery Institute.