Pedigree dog breeds are genetically isolated and inbred populations with characteristics specific to each breed. Some breeds carry genetic diseases which affect the health of the animals, but may also serve as a valuable model to identify genes involved in human disease. In the Border Collie breed in Australia, the identification of two disease genes would enable breeders to DNA test their animals and prevent future cases. Over 530 samples were collected to identify the genes responsible for these diseases through linkage mapping and candidate gene approaches. Collie Eye Anomaly (CEA) defines a group of symptoms that cause the incorrect development of different regions within the eye, and may also result in the detachment of the retina. The presence of the disease in different breeds of collies suggests that the disease originated before the differentiation of the collie breeds. The CEA gene was mapped to a region of CFA37, but the disease gene was identified by another research group. Neuronal Ceroid Lipofuscinosis (NCL) is a fatal neurodegenerative disorder that affects Border Collie dogs from approximately 16 months of age. The disease is inherited in an autosomal recessive manner and affected animals display a range of physiological and behavioural symptoms that include loss of muscular control, nervousness and sometimes aggression. Due to the debilitating nature of the disease, dogs rarely survive beyond 28 months of age. Microsatellite markers were used to exclude the Border Collie NCL gene from the region of the English Setter NCL gene (homolog of human NCL gene CLN8). Further work mapped the disease gene to CFA22, in a region containing the homolog for CLN5, one of the identified human disease genes for NCL. Subsequent sequencing of canine CLN5 revealed a nonsense mutation (c.619C>T, Q206X) that co-segregated with NCL in Border Collie pedigrees. This truncation mutation resulted in a protein product of similar size to some mutations identified in human CLN5 and therefore the Border Collie may make a good model for future NCL studies. With DNA testing now available, breeders of Border Collies can now ensure that no animal will die of NCL.
| Identifer | oai:union.ndltd.org:ADTP/234089 |
| Date | January 2006 |
| Creators | Melville, Scott Andrew, Biotechnology & Biomolecular Sciences, Faculty of Science, UNSW |
| Publisher | Awarded by:University of New South Wales. School of Biotechnology and Biomolecular Sciences |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | Copyright Scott Andrew Melville, http://unsworks.unsw.edu.au/copyright |
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