An important factor when considering the impact of breeding decisions on health is how heritable a condition is. This is particularly important for complex diseases, where the observed phenotype (disease) is due to a combination of genes and environment.
Heritability is the measure used to describe the proportion of liability which can be ascribed to genetic rather than environmental effects. Good heritability studies require data with minimal bias: affected and unaffected diagnoses must be equally likely to be submitted to the database. The disease diagnosis or phenotypic evaluation must be consistent and provided by a person trained in the diagnosis or evaluation of the condition. Quantitative measurement is preferred, if appropriate, rather than a simple affected/unaffected status.
Heritability investigations conducted at the Animal Health Trust:
Hip and elbow score in 15 breeds
Lewis TW, Blott SC, Woolliams JA. (2013) Comparative analyses of genetic trends and prospects for selection against hip and elbow dysplasia in 15 UK dog breeds. BMC Genet. Mar 2; 14: 16.
Woolliams JA, Lewis TW, Blott SC. (2011) Canine hip and elbow dysplasia in UK Labrador retrievers. Vet J. 189: 169-176. Review.
Lewis TW, Ilska JJ, Blott SC, Woolliams JA. (2011) Genetic evaluation of elbow scores and the relationship with hip scores in UK Labrador retrievers. Vet J. 189: 227-233.
Lewis TW, Woolliams JA, Blott SC. (2010) Genetic evaluation of the nine component features of hip score in UK Labrador Retrievers. PLoS One 5(10): e13610.
Lewis TW, Blott SC, Woolliams JA. (2010) Genetic evaluation of hip score in UK Labrador Retrievers. PLoS One 5(10): e12797.
Syringomyelia in the Cavalier King Charles Spaniel
Lewis T, Rusbridge C, Knowler P, Blott S, Woolliams JA. (2010) Heritability of syringomyelia in Cavalier King Charles spaniels. Vet J. 183: 345-347
Mitral valve disease in the Cavalier King Charles Spaniel
Lewis T, Swift S, Woolliams JA, Blott S. (2010) Heritability of premature mitral valve disease in Cavalier King Charles spaniels. Vet J. 188: 73-76
Sensorineural deafness in the Border Collie
De Risio L, Lewis T, Freeman J, de Stefani A, Matiasek L, Blott S. (2011) Prevalence, heritability and genetic correlations of congenital sensorineural deafness and pigmentation phenotypes in the Border Collie. Vet J. 188: 286-90
Health and behaviour traits in guide dogs
We are currently working with Guide Dogs UK to estimate heritabilities for several health conditions as well as behavioural traits.