No Evidence for Recent Selection at FOXP2 among Diverse Human Populations

Abstract

FOXP2, initially identified for its role in human speech, contains two nonsynonymous substitutions derived in the human lineage. Evidence for a recent selective sweep in Homo sapiens, however, is at odds with the presence of these substitutions in archaic hominins. Here, we comprehensively reanalyze FOXP2 in hundreds of globally distributed genomes to test for recent selection. We do not find evidence of recent positive or balancing selection at FOXP2. Instead, the original signal appears to have been due to sample composition. Our tests do identify an intronic region that is enriched for highly conserved sites that are polymorphic among humans, compatible with a loss of function in humans. This region is lowly expressed in relevant tissue types that were tested via RNA-seq in human prefrontal cortex and RT-PCR in immortalized human brain cells. Our results represent a substantial revision to the adaptive history of FOXP2, a gene regarded as vital to human evolution.

Multimodal communication and language origins: integrating gestures and vocalizations

“…For instance, animal vocalizations were thought merely to reflect the emotional arousal of the producer and thus not to represent intentional communication (Tomasello, 2008). Recent research, however, not only shows that language might be much older than previously recognized (Krause et al, 2007;Dediu & Levinson, 2013;Atkinson et al, 2018), but also is best regarded as an 'evolutionarily stratified system' (i.e. consisting of different abilities of different evolutionary origins; Levinson & Holler, 2014).…”

Systematic detection of brain protein-coding genes under positive selection during primate evolution and their roles in cognition

“…Functional studies also showed that mice carrying a "humanized" version of FOX2 display qualitative changes in ultrasonic vocalization 13 . However, these reports targeting only specific genes sometimes provide contradictory results 14 and other studies have reported a greater sequence conservation of the brain protein-coding genes compared to other tissues [15][16][17] , suggesting that the main substrate of evolution in the brain reside in regulatory changes of gene expression [18][19][20] and splicing 21 . It was also shown that more genes underwent positive selection in chimpanzee evolution than in human evolution contradicting the widespread brain-gene acceleration hypothesis of human cognition origins 22 .…”

DRD2andFOXP2are implicated in the associations between computerized device use and psychiatric disorders

“…The FOXP2 locus encodes a brain-expressed transcription factor strongly implicated in the evolution of speech and language but recent studies report no evidence of recent selection in humans. 45 Nevertheless, FOXP2 is consistently implicated in the human ability to communicate via complex speech. 37 Additionally, we uncovered multiple genetically correlated traits shared between ADHD and PhoneUse in the combined and sex-stratified cohorts, including "age at first sexual intercourse" and "risk taking."…”