FOXP2: Genetic Mutation

An unprecedented study, conducted at the Max Planck Institute for Evolutionary Anthropology, discovered that genetics may have played a role in the development of language in modern hominins. 

In 2002, scientist Svante Pääbo conducted an experiment that tested whether a gene, called FOXP2, had specific ties to language in modern hominins.  FOXP2 was discovered during a study of “a family who had a history of profound speech and language disorders;” “FOXP2 was the first gene found to be involved in language production” (Warren).  In the experiment, Pääbo and her colleagues “relied on a small set of 20 people on whom the researchers conducted Sanger sequencing of three FOXP2 introns;” this set was composed of “seven individuals from Africa, four from Europe, one from South America, five from Asia, and three from Australia and Papua New Guinea” (GenomeWeb).  After conducting the tests, their analysis discovered “that humans carry two mutations to FOXP2 not found in any other primates, and this genetic variation evidenced that a “‘selective sweep’ — in which a beneficial mutation quickly becomes common across a population” — occurred (Warren).  Pääbo also reported that this “change to FOXP2 seemed to have happened in the past 200,000 years” (Warren).  While her “paper has been cited hundreds of times in the scientific literature,” there are key elements to this experiment that have drawn criticism (Warren).  For instance, Pääbo conducted this experiment with a small data set of 20 people.  Especially for a discovery this monumental, she should have repeated her experiment with a larger data sample.  Brenda Henn, “a population geneticist at the University of California” and senior author from Stony Brook University, addressed this issue by stating her concerns “that an over-reliance on small data sets has skewed our understanding of what makes humans unique” (Warren).  In fact, Henn and researchers from Stony Book “‘wanted to test whether … [Pääbo’s] hypothesis stood up against a larger, more diverse dataset that more explicitly controlled for human demography’” (GenomeWeb).  Initially, Hen and her colleagues “did find an indication of positive selection on FOXP2;” however, “when they separated out African individuals and individuals whose ancestors underwent the out-of-Africa expansion, that signal disappeared” (GenomeWeb).  Henn’s findings led population geneticist and co-author of Pääbo’s paper, Elizabeth Atkinson, to reexamine Pääbo’s and Henn’s research; Atkinson then concluded that “the 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” and that the selective sweep thought to have been discovered cannot be verified (Warren).  In addition, another study “found that Neanderthals carried the same mutations” as modern hominins, suggesting “that the modifications to FOXP2 happened before the two groups split, more than half a million years ago” (Warren).  

FOXP2

Nevertheless, Simon Fisher, “director of the Max Planck Institute for Psycholinguistics in Nijmegen, the Netherlands, and a coauthor of the 2002 study,” affirms that even “if there was no recent evolution of FOXP2, there is still plenty of evidence that the gene is involved in language” (Warren).  That is, it is evidential that mutations “in FOXP2 cause language disorders in humans, and in mice the gene is important for vocalizations and movement — both functions that are crucial to human speech” (Warren).  Fisher also states that FOXP2 is only “‘one piece of a complex puzzle,’” which can only be solved through further delving into the complex genetics of language and continuing to conduct experiments on a diverse sample of people (Warren).  

Bibliography

“FOXP2 .” Cell, Cell, www.cell.com/cell/fulltext/S0092-8674(18)30851-1.

GenomeWeb. “New Analysis Fails to Find Recent, Human-Specific Selection at Language-

Linked FOXP2 Gene.” Accessed October 25, 2018. https://www.genomeweb.com/genetic-research/new-analysis-fails-find-recent-human-specific-selection-language-linked-foxp2-gene#.W9Mu7lJReYU

Warren, Matthew. “Diverse genome study upends understanding of how language evolved.”

Nature, August 2, 2018. https://www.nature.com/articles/d41586-018-05859-7