Deafness In Beautiful Spotted Dogs
I consider Dalmatian is the most beautiful breed. Unfortunately, their beautiful coat is likely to be responsible for the inherited disorder Congenital Sensorineural Deafness (CSD) either unilaterally deaf or bilaterally deaf.
This disorder presents in more than 54 different kinds of breed. However, the prevalence of Dalmatian having deafness is twice as high in other breeds.
Studies about this hereditary disorder were carried out by scientists. Genetic variance, gender, eye colour, spot and coat color and heritability were investigated. So, obviously, this disorder should be inherited by parents by passing their genetic information to their offspring. Therefore, if one or both of the parents are affected, the offspring will have a higher chance to be deaf. Gender does not determine the prevalence of deafness in Dalmatian. Dalmatian with heterochromia iridis (i.e. one brown eye with one blue eye) or both blue eyes is very likely to be deaf. In addition, black or liver spotted Dalmatians do not have an incidence to be deaf. Studies show that Dalmatian that does not have a patch is more likely to be affected than that has a patch. Strong expression of Sw allele reduces melanocytes and cause deafness and blue eyes. Weak expression of this allele associates with pigmentation that leads to patches on coat.
To conclude, white genes that are responsible for pigment on white coat are significant. In other words, pigmentation genes that are not related to white producing do not have an important role to determine deafness in Dalmatian.
primary sources
Strain G. M., 2004, ‘Deafness prevalence and pigmentation and gender
Rak S. G., Distl O., 2003, ‘Congenital sensorineural deafness in dogs: a molecular genetic approach toward unravelling the responsible genes’ Veterinary Journal, vol. 169, no. 22, pp.188-196 access article here
Cargill E. J., Famula T. R., Strain G. M., Murphy K. E., 2003,’ Heritability and Segregation Analysis of Deafness in U.S. Dalmatians’, Genetics, vol. 166, pp.1385-1393 access article here
by Yee Tak Edith Shum
student no. 41366053
