Figure 1.

Pedigree of the four litters investigated. Filled symbols represent dogs with eye malformations. Open symbols represent dogs in which no eye abnormalities were observed by their owners. These dogs were not specifically examined by an ophthalmologist (or the results of such an examination were not available for the study). Deceased or euthanized animals are indicated by strikethrough symbols. SIX6:c487C>T genotypes are indicated for all dogs, from which a blood sample was available. Heterozygous C/T genotypes are indicated in red. Please note that all three available cases, but also five dogs with no apparent eye phenotypes, carried the mutant T-allele.