Evidence for the Presence of the Fifth Pharyngeal Arch During the Chick Development/Evidencia de la Presencia del Quinto Arco Faringeo Durante el Desarrollo del Polluelo

• Published in: International journal of morphology 2024-09, Vol.42 (5), p.1322
• Main Authors: Wang, Jinbao, Liang, Jiaying, Wang, Yajun, Tao, Hengxun, Pu, Qing, Kuerten, Stefanie, Tiemann, Inga, Theis, Susanne, Patel, Ketan, Huang, Ruijin
• Format: Article
• Language: Spanish
• ISSN: 0717-9367

The pharyngeal arch (PA) is a transient structure of vertebrate embryos. Their number varies from species to species; nine in lampreys, seven in teleosts, and six in amniotes. Each pharyngeal arch contains a nerve and an artery as well as skeletomuscular elements. There has been a long-standing controversy about the formation of the fifth PA. Here, we investigated the formation of the fifth PA by tracking the distribution of neural crest cells in pharyngeal arches in chick embryos. Fertilized chick and quail eggs were used. Neural crest cells were detected by using quail-chick cell tracing technique and in ovo electroporation of EGFP constructs. Our results showed that neural crest cells from the post-otic level contributed to all post-otic pharyngeal arches (PA3-6). In contrast, neural crest cells from the somite 1-3 level avoided to invade the third pharyngeal arch, although they gave rise post-otic pharyngeal arches. Based on the trajectory of neural crest cells, the fifth pharyngeal arch was visible between the fourth and sixth pharyngeal arch, although it was considerably smaller compared to other arches. The fifth PA forms during early development at least in avian species. It is closer to the sixth PA than the fourth PA. This is in line with the formation of the fifth PAA, which can form a bypass and even fuse with the sixth PAA. KEY WORDS: Fifth pharyngeal arch; Neural crest; Chick embryos; Quail chick chimera; In ovo-electroporation. El arco faringeo (AF) es una estructura transitoria de los embriones de vertebrados. Su numero varia de una especie a otra; nueve en lampreas, siete en teleosteos y seis en amniotas. Cada arco faringeo contiene un nervio y una arteria, asi como elementos esqueleto musculares. Ha existido una larga controversia sobre laformacion del quinto arco faringeo. En este trabajo investigamos la formacion del quinto AF mediante el seguimiento de la distribucion de las celulas de la cresta neural en los arcos faringeos en embriones de pollo. Se utilizaron huevos de pollito y codorniz fertilizados. Las celulas de la cresta neural se detectaron mediante la tecnica de rastreo de celulas de polluelos de codorniz y la electroporacion in ovo de construcciones de EGFP. Nuestros resultados mostraron que las celulas de la cresta neural del nivel postotico contribuyeron a todos los arcos faringeos postoticos (AF3-6). Por el contrario, las celulas de la cresta neural del nivel somita 1-3 evitaron invadir el tercer arco faringeo, aunque dier