The genetics of coat variation is a powerful system for studying the fundamental aspects of gene action and the evolutionary mechanisms that give rise to morphological diversity. The domestic dog is an ideal platform for this approach due to the variety of coat colours, textures and patterns represented among modern breeds, and a unique population history that facilitates efficient and precise gene localization. Topics discussed are evolutionary history of the domestic dog and application to gene mapping; pigment cell development and survival; generalized pigment dilution; pigment-type switching; genetics of hair structure in the domestic dog; and hair follicle development and biology.

This review deals mainly with the results of a long-term experiment carried out at the Institute of Cytology and Genetics, Novosibirsk (Russia), on selection for behaviour in the arctic fox. It includes consideration of the indirect effects of selection on phenotype, the skull, seasonal reproduction, development, and the endocrine and neurotransmitter systems. Implications of this work for evolution of the domestic dog are discussed.

This chapter discusses an overview of the genetic basis of canine orthopaedic conditions, as well as an update on the molecular genetics of selected canine orthopaedic traits. The genetic and molecular basis of selected canine disorders with orthopaedic manifestations such as congenital bone and joint diseases, paediatric bone and joint diseases, and adult bone and joint diseases are discussed.

The transglutaminase 1 gene (TGM1) encodes an enzyme necessary for cross-linking the structural proteins that form the cornified envelope, an essential component of the outermost layer of the skin, the stratum corneum. Reported here is the complete coding region of canine TGM1, its chromosome localization, and its map position in the integrated canine linkage-radiation hybrid map. Canine TGM1 consists of 2,448 nucleotides distributed over 15 exons. The nucleotide sequence has 90% identity to human TGM1. The deduced canine TGM1 protein is 816 amino acids long and is 92% identical to human TGM1. Using fluorescence in situ hybridization, we localized canine TGM1 to dog (Canis familiaris) chromosome 8 (CFA 8q). Canine TGM1 localized to CFA 8 on the integrated linkage-radiation hybrid map in the interval FH2149–MYH7. Characterizing the coding region of canine TGM1 is a first step in examining the role of this enzyme in normal and defective cornification in the dog.

This chapter aims to summarize the basic reproductive physiology of the male and female dog, including the latest discoveries within this field, and also to give an update on the applications of new reproductive technologies in this species.