Pharyngeal development and evolution

Anthony Graham

Professor of Developmental Biology

Schematic of the pharyngeal arches (PA) in side view and in section (B) (C) at later stages the second pharyngeal arch expands to cover the more posterior arches.
Schematic of the pharyngeal arches (PA) in side view and in section (B) (C) at later stages the second pharyngeal arch expands to cover the more posterior arches.

The pharynx is a complex region of the body that is involved in numerous critical functions and in pondering its mature anatomical organisation it can be difficult to discern the rules that underpin its construction. However, there is an underlying logic that is evident if one considers how this region of the body is formed during embryogenesis. The pharyngeal apparatus has its developmental origin in a series of bulges found on the lateral surface of the head at early stages, the pharyngeal arches, and it is with the development of these structures that our lab is concerned. This is a complex process as the pharyngeal arches comprise of a number of disparate embryonic cell types. Externally the arches are circumscribed by ectoderm, internally by endoderm and each has a mesenchymal core of neural crest cells that surround a central group of mesodermal cells. These different embryonic populations that constitute the arches must be co-ordinated so that each will form the appropriate derivative at the right time and place: nerves, muscle, skeleton and epithelial specialisation, and that those derivatives have the morphology associated with their specific pharyngeal arch.

Our aim is to understand how the early development of the pharyngeal arches is organised and additionally how these become remodelled during development to yield the mature anatomical organisation. Comprehending the development of the pharynx is an important goal in itself, particularly as this is a much understudied region, but it is also significant as it will inform us of the aetiological basis of defects that affect this region of the body. Such defects include DiGeorge syndrome and the presence of branchial cleft and pouch anomalies. Finally, another pervasive influence of the organisation of the pharynx is its evolutionary history and many of the events directing the development of the pharynx only make sense when seen in the light of evolution.

I have two PhD studentships available:

Applications are now open for a PhD: Signalling pathways controlling the generation of the pharyngeal arches. The deadline is 04 March 2019. Follow the link for more information about this Anatomical Society-funded studentship and to apply.

I also have an MRC DTP PhD studentship available: 'Investigating the developmental basis for unique wound healing properties of facial skin' (project 16.1, Theme 1). Applications for the MRC DTP studentships have closed - this project is only available to those who secure a place in the 2019 MRC DTP student cohort. Follow the link for details of the MRC DTP project.

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