Nature vs. Nurture: Language

This week, the language alerts brought back several articles on Neanderthals, and the possibility that they shared the ability to create language with the modern human. Johannes Krause and his colleagues at the Max Planck Institute for Evolutionary Anthropology "extracted DNA from two 38,000-year-old Neanderthals collected from El Sidron Cave in Austurias, Spain," and found a specific form of the gene FOXP2 or Forkhead Box P2--a variant form similar to that of humans that has been linked to language development.

FOXP2 is required for proper brain and lung development. Mouse studies and known gene mutations suggest its involvement in the development of tissues in these areas, as well as the gut. Scientists first discovered the gene's role in speech and language in 2001, when they studied the Pakistani KE family, in which "half the members suffered from a disorder that interfered with their ability to understand grammar and to speak." Brain scans of both affected and unaffected family members "limited the affected region to a spot on chromosome 7," and further gene sequencing pinpointed a point mutation in this chromosome. This is now called the FOXP2 gene, and considered an important language gene, " not only in humans but also in animals.

Indeed, many related animal-studies I found suggest FOXP2 as one of the specific genes that enable language learning. Though on humans (and Neanderthals) carry the version that allows for word formulation, grammar competence and complex language, many birds, mammals, fish and reptiles carry similar FOXP2 genes, with a difference of only a few amino acids. And studies on zebra finch shows that levels of FOXP2 in the brain "significant change when males are learning or practicing their song, but not when they are performing their song for females." If this applies also to human, it could have provide great insight into the human ability to learn language, and possibly also into the difference between learning a first and a second or third language. In humans, however, studies have only linked FOXP2 mutations with problems in the motor coordination required for speech. MRIs of individuals with mutated copies of the gene also reveal "underactivation of Broca's area and the putamen--brain centers thought to be involved in language tasks." In other words, FOXP2 could be associated with language only on a superficial level, affecting our ability to express language rather than that of producing language.

I am constantly amazed at the intricate complexity of the human body in general, and the human mind in particular, but it's hard to imagine how the evolution of ONE single gene by a few amino acids could possibly make a difference as significant as the human language. I have in fact always believed language to be an acquired skill, something of nurture that we learn through social interaction out of social necessity. This article did suddenly remind me, though, that our very bodies make us human--one of those basic yet profound facts that many kids seem to know, and many knowledgeable, analytical adults seem to forget. (That sounded funny, didn't it? =D)

Another interesting fact: By comparing different FOXP2 genes in different people, scientists have estimated the time our version of FOXP2 developed through natural selection to about 100,000 years ago--"the time when archaeological evidence suggests that we began using language."



Sources:

• Article: Neanderthals: Did They Have Language?
• FOXP2 - Wikipedia
  
• Another article I found: From Genes to Word