ブラウン大学の生物学者が率いるチームは、鳴禽類が歌を覚えるのと同じ特殊な脳領域がキツツキにも存在することを発見し、コミュニケーションを図るためのドラミングが同様の方法で進化したことを示唆している。 A team led by a Brown biologist discovered that the same specialized brain area that helps songbirds learn their songs also exists in woodpeckers, suggesting that the communicative drumming evolved in a similar way.
2022-09-20 ブラウン大学
キツツキの前脳に、歌うことでコミュニケーションを図る鳥類と解剖学的に類似した特殊な遺伝子発現の証拠を発見した。
研究チームは、鳥類が歌を作ったり声を出したりする運動制御を発達させたのと同じ脳メカニズムが、キツツキが太鼓を叩いてコミュニケーションをとるシステムの発達にも寄与していると考えている。
研究室では、7種の鳥類について、同じ遺伝子発現の特殊化の兆候を探った。その結果、キツツキだけが、発声学習を行うことが知られている鳥類の歌唱システムと解剖学的に類似した前脳領域を有しており、特殊性を示す証拠を発見した。
<関連情報>
- https://www.brown.edu/news/2022-09-20/woodpeckers-0
- https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3001751
キツツキの縄張り意識に関連する前脳核は、鳴禽類の発声学習を可能にする核と類似している Forebrain nuclei linked to woodpecker territorial drum displays mirror those that enable vocal learning in songbirds
Eric R. Schuppe,Lindsey Cantin,Mukta Chakraborty,Matthew T. Biegler,Electra R. Jarvis,Chun-Chun Chen,Erina Hara,Mads F. Bertelsen,Christopher C. Witt,Erich D. Jarvis ,Matthew J. Fuxjager
PLOS Biology Published: September 20, 2022
DOI:https://doi.org/10.1371/journal.pbio.3001751
Abstract
Vocal learning is thought to have evolved in 3 orders of birds (songbirds, parrots, and hummingbirds), with each showing similar brain regions that have comparable gene expression specializations relative to the surrounding forebrain motor circuitry. Here, we searched for signatures of these same gene expression specializations in previously uncharacterized brains of 7 assumed vocal non-learning bird lineages across the early branches of the avian family tree. Our findings using a conserved marker for the song system found little evidence of specializations in these taxa, except for woodpeckers. Instead, woodpeckers possessed forebrain regions that were anatomically similar to the pallial song nuclei of vocal learning birds. Field studies of free-living downy woodpeckers revealed that these brain nuclei showed increased expression of immediate early genes (IEGs) when males produce their iconic drum displays, the elaborate bill-hammering behavior that individuals use to compete for territories, much like birdsong. However, these specialized areas did not show increased IEG expression with vocalization or flight. We further confirmed that other woodpecker species contain these brain nuclei, suggesting that these brain regions are a common feature of the woodpecker brain. We therefore hypothesize that ancient forebrain nuclei for refined motor control may have given rise to not only the song control systems of vocal learning birds, but also the drumming system of woodpeckers.
