Novel expression sites and genetic diversity of FoxP2 in Lake Malawi cichlids
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FoxP2 is a forkhead box-family transcription factor intricately linked to the development of learned motor skills, especially language in humans or vocalizations in other animals. It plays a prominent role in development and continues to be expressed in the adult. The gene has been thoroughly described in the brain, but transcripts have also been documented in areas such as in the lungs of mice (Shu et al, 2007). Mutations or deletions of FoxP2 cause widespread defects in brain morphology, vocalization ability, balance and coordination, and even lung development. Broad conservation of FoxP2‟s role in motor control and vocalization suggests the gene may play a similar role in vocally diverse Lake Malawi cichlids. Here, we probe cichlid FoxP2 expression using in-situ hybridization throughout development, sequence and annotate the FoxP2 gene across seven representative cichlid species, and search for polymorphisms. Expression in the brain, swimbladder, pharyngeal arches, and fins suggest FoxP2 plays a role not only in sensory development and fine motor control, but also in the development of non-neural sound-producing structures as well as the development or innervation of skeletal muscle. Genetic analysis of FoxP2 reveals polymorphisms which may be a source of species diversity in the development of any of the above functions, including vocalization. Two polymorphisms of note result in two amino acid changes near the DNA-binding domain of FoxP2. The natural phenotypic diversity of cichlid fishes makes them excellent candidates for further studies of the function and evolution of FoxP2.