Genes for Speech May Not Be Limited to Humans
It is widely believed that mice have no or rather extremely limited neural circuitry that allow them speak, however, studies have shown that mice do in fact communicate using a form of vocalization. Dr. Jarvis, the lead investigator studied the effects of mutation in the Forkhead Box Protein #2 (FOXP2) gene, which regulates the vocalization patterns in humans. Those whom have mutations in this gene tend to struggle with speech impediments. They are unable to master the “coordinated sequences of syllables/phenomes for fluent speech.”2 Dr. Jarvis and his team found that the same effect can occur in mice as well. Even more so, according to Dr. Jarvis, this supports the hypothesis that the FOXP2 gene affects not only humans, but all mammals.
The study compared the differences in the sequence and duration of the ultrasonic vocalizations (USVs) of heterozygous male mice with the FOXP2 mutation and healthy wild-type male mice. The results showed that wild-type mice were able to produce complex vocal communication with ease in the presence of active female mice. Heterozygous mice with the FOXP2 deficiency were three times likely to have difficulty in producing complex syllable length and variability over a period of time.
The vocal motor neurons of heterozygous mice were also studied and Dr. Jarvis and his team found that they are spread more widely across the cortex than that of wild-type mice. This leads them to believe that the FOXP2 gene mutations not only changes the quality of communication, but the location of the neurons in both mice and humans.
Although previously the FOXP2 gene was thought to play a slight role, Dr. Jarvis "believes the FOXP2 gene already had a pre-existing role in regulating vocal communication before human communication evolved."1
1. Frontiers. "Genes for speech may not be limited to humans: Study shows vocal communication in mice is affected by the same gene needed for speec h in humans." ScienceDaily. ScienceDaily, 15 November 2016. www.sciencedaily.com/releasses/2016/11/161115114333.htm.
2. Johnathan Chabout, Abhra Sarkar, Sheel R. Patel, Taylor Radden, David B. Dunson, Simon E. Fisher, Erich D. Jarvis. A Foxp2 Mutation Implicated in Human Speech Deficits Alters Sequencing of Utrasonic Voclizations in Adult Male Mice.Frontiers in Behavioral Neuroscience, 2016; 10 DOI: 10.3389/fnbeh.2016.00197