Perhaps one of the most fascinating lines of research opened up by the discovery of FOXP2 is the evolutionary origins of speech and language. “FOXP2 stands out,” says Dr Fisher. “It’s very unusual from an evolutionary point of view.”
The FOXP2 gene seems to also be critical in vocal learning even in widely different species:
Fascinating.FoxP2 Expression in Avian Vocal Learners and Non-Learners
Abstract: Most vertebrates communicate acoustically, but few, among them humans, dolphins and whales, bats, and three orders of birds, learn this trait. FOXP2 is the first gene linked to human speech and has been the target of positive selection during recent primate evolution. To test whether the expression pattern of FOXP2 is consistent with a role in learned vocal communication, we cloned zebra finch FoxP2 and its close relative FoxP1 and compared mRNA and protein distribution in developing and adult brains of a variety of avian vocal learners and non-learners, and a crocodile. We found that the protein sequence of zebra finch FoxP2 is 98% identical with mouse and human FOXP2. In the avian and crocodilian forebrain, FoxP2 was expressed predominantly in the striatum, a basal ganglia brain region affected in patients with FOXP2 mutations. Strikingly, in zebra finches, the striatal nucleus Area X, necessary for vocal learning, expressed more FoxP2 than the surrounding tissue at post-hatch days 35 and 50, when vocal learning occurs. In adult canaries, FoxP2 expression in Area X differed seasonally; more FoxP2 expression was associated with times when song becomes unstable. In adult chickadees, strawberry finches, song sparrows, and Bengalese finches, Area X expressed FoxP2 to different degrees. Non-telencephalic regions in both vocal learning and non-learning birds, and in crocodiles, were less variable in expression and comparable with regions that express FOXP2 in human and rodent brains. We conclude that differential expression of FoxP2 in avian vocal learners might be associated with vocal plasticity.
If I worked in a genetics lab with the appropriate equipment and techniques, the first thing I'd want to try would be to replace a parrot's FOXP2 gene with the human version, then hatch a chick with the resulting genome and see whether there's a quantum leap in its ability to learn and use grammar-based language.