“A paper published in 2002 (Enard et al., Nature 418, 869-872) claimed there was a selective sweep relatively recently in human evolutionary history that could largely account for our linguistic abilities and even help explain how modern humans were able to flourish so rapidly in Africa within the last 50-100,000 years,” says senior author Brenna Henn, a population geneticist at Stony Brook University and UC Davis. “I was immediately interested in dating the selective sweep and re-analyzing FOXP2 with larger and more diverse datasets, especially in more African populations.”
Henn says that when the original 2002 work was done, the researchers did not have access to the modern sequencing technology that now provides data on whole genomes, so they only analyzed a small fraction of the FOXP2 gene in about 20 individuals, most of whom were of Eurasian descent. “We wanted to test whether their hypothesis stood up against a larger, more diverse dataset that more explicitly controlled for human demography,” she says.
“In the past five years, several archaic hominin genomes have been sequenced, and FOXP2 was among the first genes examined because it was so important and supposedly human specific,” says first author Elizabeth Atkinson of Stony Brook University and the Broad Institute of Harvard and MIT. “But this new data threw a wrench in the 2002 paper’s timeline, and it turns out that the FOXP2 mutations we thought to be human specific, aren’t.”
That is a setback. Of ourse, there are those who believe that IQ tests are unfair to apes but even they… More to the point:
“FOXP2 is still a textbook example taught in every evolutionary biology class despite the recent data from archaic DNA,” says co-author Sohini Ramachandran, an evolutionary and computational biologist at Brown University. “So while we’re not questioning the functional work of FOXP2 or its role in language production, we’re finding that the story of FOXP2 is really more complex than we’d ever imagined.” Paper. (open access) – Elizabeth Grace Atkinson, Amanda Jane Audesse, Julia Adela Palacios, Dean Michael Bobo, Ashley Elizabeth Webb, Sohini Ramachandran, Brenna Mariah Henn. No Evidence for Recent Selection at FOXP2 among Diverse Human Populations. Cell, 2018; DOI: 10.1016/j.cell.2018.06.048
It’s interesting (and a good sign) that researchers even raise the issue of out of date textbooks. More of them should.
Brenna Henn, senior author of the latest paper and a population geneticist at the University of California, Davis, is now keen to revisit other genes that have been considered important to human evolution, such as one called Microcephalin, which has been linked to brain development. She worries that an over-reliance on small data sets has skewed our understanding of what makes humans unique.
“If you’re asking a question about the evolution of humans as a species,” says Atkinson, “you really do need to include a diverse set of people.” More.
Yes, that might help. But it might not provide the type of gene-for-this, gene-for-that pop science news stories that are a staple of current media coverage.
Meanwhile, at Evolution News,
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. David Klinghoffer, “Update: Still No Evolutionary Explanation for Human Language” at Evolution News
See also:Human evolution: FoxP2 and speech (2009)
There’s a gene for that… or is there?