The heads of primates, including humans, all have the same basic parts, yet every head is different. Craniofacial variation has important implications for diet, defense, posture, balance, hearing, vision, and the accommodation of the expanding primate brain. The skull is a complex adaptive structure, and the question naturally arises pertaining to the genetic mechanisms that assemble and coordinate its shape. This project will determine whether variation in head shape occurs along similar anatomical axes among living monkeys and apes, their fossil ancestors, a pedigree of 800 extant baboons, and in laboratory mice. Computerized tomography (CT) scans will be acquired from these heads and used to measure variation in three dimensions. The genes responsible for this variation will be identified using data from baboon and mouse. Developmental pathways are shared among mammals, so mice provide an important comparative and experimental basis for primate findings. The manner by which genes structure variation in head shape will be investigated by combined comparative DNA sequence and bioinformatic analysis, and by engineering similar changes in mice to those seen in baboons. Many genes doubtlessly contribute to structures like the head, and a general challenge to modern evolutionary and developmental genetics generally is to understand whether some genes are repeatedly involved in similar changes in complex traits over the millions of years and different branches of evolution, or whether different genes in the shared developmental pathways are responsible in each instance.
The project will generate a large amount of data which will be posted on a publicly accessible website along with information on analytical approaches and analyses. The PIs have a strong record of training women and minority students and they will continue this tradition at all levels from undergraduate to postdoctoral. Human evolutionary studies have a strong public appeal and this project will be exceptionally popular to the public media.
