Phylogenomic analysis of vocal fold length evolution reveals links between vocal and auditory systems in terrestrial mammals.

Vocal fold length is a primary anatomical determinant of pitch and fundamental frequency in terrestrial mammal vocalizations, playing a key role in social communication, mate attraction, and competition. However, its phenotypic diversification and genetic basis remain unclear. Here, using a phylogenetic genotype-to-phenotype mapping (PhyloG2P) framework to 75 species representing Primates, Carnivora, and Artiodactyla, we investigate the evolutionary dynamics and genetic architecture of relative vocal fold length (RVFL), accounting for allometric trends. Phylogenetic comparative analyses reveal similar patterns of RVFL variation among orders and strong adaptive responses supporting the acoustic size exaggeration hypothesis. Correlation analyses further reveal the potential driving role of social organization in RVFL evolution. Comparative genomics identifies 25 hearing-related genes showing rapid evolution, positive selection, lineage-specific mutations, and coevolution with RVFL, suggesting a reciprocal evolutionary interplay between vocal and auditory systems. This genetic link is supported by laryngeal MRI evidence from wild-type and Pjvk knock-out mice, where PJVK is identified as a candidate gene through our PhyloG2P analyses. Additionally, pathways related to peptide hormone secretion and neural regulation appear to mediate RVFL variation. Together, these findings advance our understanding of the genetic and evolutionary mechanisms driving vocal fold diversity in terrestrial mammals and highlight the links between vocal and auditory systems, offering new insights into the origins of vocal communication.