This special topic issue on Veterinary Cytogenetics is dedicated to the Swedish scientist Ingemar Gustavsson, one of the pioneers of domestic animal cytogenetics, whose ground-breaking research has shaped this discipline for over 40 years. During his long and productive career he focused on chromosomes and their fundamental role in animal physiology, fertility, health and production in the context of agriculture and veterinary medicine, and he made important contributions to our understanding of mitosis, meiosis, chromosome integrity, and the transmission of chromosomal variation in domestic animals. This collection of reviews and original articles illustrates how the field of veterinary cytogenetics evolved from the study of the structure and number of chromosomes to modern molecular cytogenetics with its refined technology for research, diagnostic, prognostic or reproductive purposes. The goal of this publication is not to present an exhaustive volume covering each area of veterinary cytogenetics, but to give examples of specific subjects tackled by research groups working mainly in Europe and North America.[-]