Editing FOXP2 (section)

=== Birds ===
In [[songbird]]s, ''FOXP2'' most likely regulates genes involved in [[neuroplasticity]].<ref name="Haesler_2007">{{cite journal | vauthors = Haesler S, Rochefort C, Georgi B, Licznerski P, Osten P, Scharff C | title = Incomplete and inaccurate vocal imitation after knockdown of FoxP2 in songbird basal ganglia nucleus Area X | journal = PLOS Biology | volume = 5 | issue = 12 | pages = e321 | date = December 2007 | pmid = 18052609 | pmc = 2100148 | doi = 10.1371/journal.pbio.0050321 | doi-access = free }}</ref><ref name="Teramitsu_2006">{{cite journal | vauthors = Teramitsu I, White SA | author-link2 = Stephanie A. White | title = FoxP2 regulation during undirected singing in adult songbirds | journal = The Journal of Neuroscience | volume = 26 | issue = 28 | pages = 7390–4 | date = July 2006 | pmid = 16837586 | doi = 10.1523/JNEUROSCI.1662-06.2006 | url = https://doi.org/10.1523/JNEUROSCI.1662-06.2006 | pmc = 2683919 }}</ref> [[Gene knockdown]] of ''FOXP2'' in area X of the [[basal ganglia]] in songbirds results in incomplete and inaccurate song imitation.<ref name="Haesler_2007" /> Overexpression of ''FOXP2'' was accomplished through injection of [[adeno-associated virus]] serotype 1 (AAV1) into area X of the brain. This overexpression produced similar effects to that of knockdown; juvenile zebra finch birds were unable to accurately imitate their tutors.<ref>{{cite journal | vauthors = Heston JB, White SA | author-link2 = Stephanie A. White | title = Behavior-linked FoxP2 regulation enables zebra finch vocal learning | journal = The Journal of Neuroscience | volume = 35 | issue = 7 | pages = 2885–94 | date = February 2015 | pmid = 25698728 | doi = 10.1523/JNEUROSCI.3715-14.2015 | url = https://doi.org/10.1523/JNEUROSCI.3715-14.2015 | pmc = 4331621 }}</ref> Similarly, in adult canaries, higher ''FOXP2'' levels also correlate with song changes.<ref name="Haesler_2004"/>

Levels of ''FOXP2'' in adult zebra finches are significantly higher when males direct their song to females than when they sing song in other contexts.<ref name="Teramitsu_2006"/> "Directed" singing refers to when a male is singing to a female usually for a courtship display. "Undirected" singing occurs when for example, a male sings when other males are present or is alone.<ref>{{cite journal | vauthors = Jarvis ED, Scharff C, Grossman MR, Ramos JA, Nottebohm F | title = For whom the bird sings: context-dependent gene expression | journal = Neuron | volume = 21 | issue = 4 | pages = 775–88 | date = October 1998 | pmid = 9808464 | doi = 10.1016/s0896-6273(00)80594-2 | s2cid = 13893471 | doi-access = free }}</ref> Studies have found that FoxP2 levels vary depending on the social context. When the birds were singing undirected song, there was a decrease of FoxP2 expression in Area X. This downregulation was not observed and FoxP2 levels remained stable in birds singing directed song.<ref name="Teramitsu_2006"/>

Differences between song-learning and non-song-learning birds have been shown to be caused by differences in ''FOXP2'' [[gene expression]], rather than differences in the amino acid sequence of the ''FOXP2'' protein.