Class Year


Document Type

Student Research Paper

Date of Creation

Spring 2020

Department 1



The pharyngeal arch arteries (PAAs) in mammals undergo asymmetric remodeling to give rise to the major blood vessels. The first and second PAAs form rudimentarily in mammalian embryos and eventually regress as the third, fourth, and sixth PAAs predominate. Cell migration, proliferation, and apoptosis drive the remodeling process, stimulated by a number of underlying molecular mechanisms. Sonic hedgehog, Hox genes, Tgfβ2, Tbx1, and a number of transcription regulators all influence PAA morphogenesis. Tbx1, which is found in the deleted region of Chromosome 22 in DiGeorge Syndrome patients, forms anterior-to-posterior and medial-tolateral gradients in the developing PAA system to promote remodeling. The transient and rudimentary presence of the first and second arteries may help establish the Tbx1 gradient, recruit cardiac neural crest cells, contribute to formation of the other arches, and advance craniofacial development.


Written for BIO 320: Developmental Biology and Senior Capstone in Biology.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.