The Georgie Project studies the genetics of complex, or quantitative, traits. Quantitative traits are characterized by phenotypes which differ by amount:  How long, how wide, how early or late, how heavy etc.  Such traits are controlled by multiple genes each exerting a partial effect on the phenotype.  Together, these genes then determine the observed phenotype of the dog.  The anatomy of the dog is an excellent example of a set of quantitative phenotypes, involving bone lengths, widths, and shapes that vary  to a small or large extent from one animal to another.  These variations can be measured precisely from x-rays (click for x-ray project).  Thanks to the wonderful cooperation and enthusiasm of many owners/breeders, we have received x-rays of more than 200 Portuguese Water Dogs from which we also have obtained blood for DNA samples.   We are in the process of analyzing the genetic basis for PWD anatomy.  We shall need to obtain between 400 and 600 sets of x-rays from genotyped dogs in order to complete this project.

    The appearance, performance and behavior of a dog are constrained by its anatomy.  Canine variation in anatomy is enormous and differences between breeds have been achieved rapidly by directed breeding.  The phenotypes achieved are excellent examples of quantitative genetics in which the proportions of the animal have been varied in a continuous manner to produce quite different animals suited to performing quite different tasks.  A wide range of anatomical variation is apparent in Portuguese Water Dogs and was documented by the results of the owner's survey.  What is the genetic potential driving the future anatomy of the breed and what constraints has this imposed on their past (or will impose on their future) appearance, behavior and performance?

    To answer such questions and to provide breeders with an understanding of their breed, we have begun a molecular genetic analysis of PWD anatomy.  Owners have been supplying us with blood (DNA for genetic analysis) and x-rays of their dogs.  From the overall anatomy of the dog (click here) we have chosen four regions to examine in detail: the skull, the fore and the hind limbs and the pelvis.  These regions are of major interest because they have a dramatic impact on the appearance and the performance of the dog (and consequently on its behavior) determining such characteristics as its gait,
speed and agility as well as its dentition or the pitch of its bark (high or low).

    Each region contains many different bones, each with different parameters determining its shape.  How do these vary genetically and how does variation of one affect or constrain the variation of another?  From the x-rays we receive, we can measure these parameters and convert the overall appearance of the dog to a series of numbers comparing the quantitative aspects of their anatomy as required for quantitative genetic analysis.  Each of these numbers represents a quantitative phenotype and these five x-rays present us with more than 70 such phenotypes controlled by a variety of genes.  The genetic analysis of these phenotypes will lead us to the genes and an understanding of how breeding controls the appearance, performance and ultimately the behavior of the Portuguese Water Dog.