These data provide generalizable proof-of-principle for this approach, and reveal molecular specializations of the growth cone, including accumulations of the growth-regulating kinase mTOR2, together with mRNAs that contain mTOR-dependent motifs3,4.
Thus, some molecular specializations of HVC potentially reflect properties that are common among subsets of song nuclei.
A primary goal of our study was to identify molecular specializations of the adult nidopallium that constitute neurochemical markers of nucleus HVC.
These markers clearly differentiate HVC from the general pallial region to which HVC belongs, and thus represent molecular specializations of this song nucleus.
Thus, some molecular specializations of a nucleus thought to be independently derived for song learning and production may be conserved across avian vocal learning lineages.
Intriguingly, we note that two songbird novel genes exhibit exclusive expression in skin (RIOK2L, URB1L3), a finding without clear precedent that points to potential unexplored molecular specializations of songbirds.
Recent evidence supports a much closer relationship between parrots and passerines than previously recognized [ 34, 72], leading to the intriguing possibility that some molecular specializations of their vocal learning circuits may have evolved in a common ancestor.
In situ hybridization revealed that while most K-Channel genes are broadly expressed in the brain, a subset is selectively expressed in song nuclei, representing molecular specializations of the vocal circuitry.
Finally, in situ hybridization analysis revealed the broad distribution of K-Channel genes in the zebra finch brain, as well as molecular specializations of key nuclei of the song system, indicating possible roles for K-Channels in production and/or maintenance of adult birdsong.
We also show that some of these genes are expressed in the brain, and that a small subset are differentially expressed in song nuclei relative to surrounding areas, representing molecular specializations of the songbird vocal control system; others are expressed in various non-neural tissues.
