The pig has many similarities in structure and function with humans including size, feeding patterns, digestive physiology, dietary habits,
kidney structure and function, pulmonary vascular bed structure, propensity to obesity, respiratory rates and social behaviors. Since the pig is an omnivore, it provides an adaptable model to evaluate chronic and acute exposures to xenobiotics such as alcohol, tobacco, feed additives and environmental pollutants. Swine have been used as models to evaluate alcoholism, diabetes, total parenteral nutrition, organ transplantation, atherosclerosis, exercise, hypertension, melanoma, nephropathy, dermal healing, shock and degenerative retinal diseases. A severe shortage of organs and tissues for transplantation has also stimulated increased consideration of pigs as a potential solution, particularly with the recent ability to genetically modified pigs to overcome acute rejection.
Research comparing different pig breeds has identified genetic differences in fat deposition of different tissues and organs. Such
information provides an experimental model for understanding obesity and nutrition (from prenatal nutrition to aged cohorts). Porcine resource populations have been selected for phenotypic variation in bone density [osteoporosis], sex-expressed nutritional and reproductive characteristics, and growth and development (embryonic, pre- and post-natal). The porcine model will also be invaluable to study host-pathogen interactions for food safety (i.e.
Salmonella), potential biological warfare agents (African swine fever and Foot and Mouth Disease) and agents that affect food security and human health (i.e. porcine endogenous retroviruses and other zoonotic diseases). Using comparative genomics has also demonstrated new models for metabolism linked to obesity-induced diabetes.
Completion of the human genome sequence provides the starting
point for understanding the genetic complexity of humans and how genetic variation contributes to diverse phenotypes and disease. It is clear that model organisms have played an invaluable role in the synthesis of this understanding. It is also noted that additional species must be sequenced to resolve the genetic complexity of human evolution and to effectively extrapolate genetic information from comparative medicine to human medicine. Certainly the
pig has been a valuable biomedical model organism and its role will expand in the future. The pig also represents an evolutionary clade distinct from primates or rodents, and thus, provides considerable power in the analysis of human genomic sequences. The pig, a domesticated eutherian mammal, has co-evolved with humans and represents a taxa with diverse selected phenotypes. The pig has a central position in the scientific and veterinary medical communities that supports the utility of securing genome sequence information. Thus, this white paper provides scientific justification for sequencing the porcine genome to identify new genes and novel regulatory elements in the pig and in humans, mice and rats. The porcine genome will serve as a reference non-primate, non-rodent, eutherian genome. The recent ability to genetically modify the porcine genome, genetically manipulate embryonic fibroblasts, and clone genetically modified somatic cells through nuclear
transfer attests to how the pig can provide relevant genetic models. This further demonstrates the unique role the pig will play in biomedical research, hence warranting the value for genomic sequencing.